Archive | November 2013

How to Use Manure in the Greenhouse | Garden Guides

How to Use Manure in the Greenhouse | Garden Guides.

Overview

Two of the major considerations for growing plants in a greenhouse environment is keeping them warm and preventing disease in the enclosed environment. Manure may play a factor in both processes. Manure has long been used to heat plants. Ancient Romans used manure as a heat and compost source in early greenhouses. Composting manure releases heat that can be used to mature plants early in hotbeds, while the composted manure may be mixed with peat moss to form a disease-free alternative to soil.

Greenhouse History

The glasshouses used to grow plants rather than to house people and art, date back to ancient Egypt where they were used to grow grapes as early as 4,000 B.C.  By 300 B.C. glasshouses were heated by manure pits and by 92 B.C. in Italy, Sergius Orata invented a heating system, with heat passing through flues in the floor.  One of the first structures for growing plants was built for the Roman emperor Nero. At the time, the specularium, glazed with mica, was made for the cultivation of cucumbers during winter months.
By 380, Italians were using hot water filled trenches to grow roses indoors. In the 1600s Europeans were using southern facing glass, stoves and manure to grow winter crops of citrus fruits. The growing sheds were called orangeries and later were heated with carts filled with burning coal.
One of the earliest greenhouses was built in Holland, by French botanist Jules Charles de Lecluse in 1599 for the cultivation of tropical and medicinal plants. By 1720 the first U.S. all-glasshouses were built in Boston and Chicago.
In European glasshouses, the favorite crops were pineapples, peaches, and grapes. They were built against masonry walls and heat came through flues built into the walls.  The first American greenhouse with glass on all sides was erected by Boston merchant, Andrew Faneuil before 1737.
The idea of growing plants in environmentally controlled areas has existed since Roman times. The Roman emperor Tiberius ate a cucumber-like[5] vegetable daily. The Roman gardeners used artificial methods (similar to the greenhouse system) of growing to have it available for his table every day of the year. Cucumbers were planted in wheeled carts which were put in the sun daily, then taken inside to keep them warm at night. The cucumbers were stored under frames or in cucumber houses glazed with either oiled cloth known as specularia or with sheets of selenite (a.k.a. lapis specularis), according to the description by Pliny the Elder.[6]

In the 13th century, greenhouses were built in Italy to house the exotic plants that explorers brought back from the tropics. They were originally called giardini botanici (botanical gardens).

‘Active’ greenhouses, in which it is possible for the temperature to be increased or decreased manually, appeared much later. Sanga yorok written in the year 1450 AD in Korea, contained descriptions of a greenhouse, which was designed to regulate the temperature and humidity requirements of plants and crops. One of the earliest records of the Annals of the Joseon Dynasty in 1438 confirms growing mandarin trees in a Korean traditional greenhouse during the winter and installing a heating system of Ondol.

The concept of greenhouses also appeared in Netherlands and then England in the 17th century, along with the plants. Some of these early attempts required enormous amounts of work to close up at night or to winterize. There were serious problems with providing adequate and balanced heat in these early greenhouses. Today, the Netherlands has many of the largest greenhouses in the world, some of them so vast that they are able to produce millions of vegetables every year.

The French botanist Charles Lucien Bonaparte is often credited with building the first practical modern greenhouse in Leiden, Holland during the 1800s to grow medicinal tropical plants. Originally only on the estates of the rich, the growth of the science of botany caused greenhouses to spread to the universities. The French called their first greenhouses orangeries, since they were used to protect orange trees from freezing. As pineapples became popular, pineries, or pineapple pits, were built.

Experimentation with the design of greenhouses continued during the 17th century in Europe, as technology produced better glass and construction techniques improved. The greenhouse at the Palace of Versailles was an example of their size and elaborateness; it was more than 500 feet (150 m) long, 42 feet (13 m) wide, and 45 feet (14 m) high.

The golden era of the greenhouse was in England during the Victorian era, where the largest glasshouses yet conceived were constructed, as the wealthy upper class and aspiring botanists competed to build the most elaborate buildings. A good example of this trend is the pioneering Kew Gardens. Joseph Paxton, who had experimented with glass and iron in the creation of large greenhouses as the head gardener at Chatsworth, in Derbyshire, working for the Duke of Devonshire, designed and built The Crystal Palace in London, (although the latter was constructed for both horticultural and non-horticultural exhibition).

Other large greenhouses built in the 19th century, included the New York Crystal Palace, Munich’s Glaspalast and the Royal Greenhouses of Laeken (1874–1895) for King Leopold II of Belgium.

In Japan, the first greenhouse was built in 1880 by Samuel Cocking, a British merchant who exported herbs.

In the 20th century, the geodesic dome was added to the many types of greenhouses. Notable examples are the Eden Project, in Cornwall, The Rodale Institute in Pennsylvania, the Climatron at the Missouri Botanical Garden in St. Louis, Missouri, and Toyota Motor Manufacturing Kentucky.

Greenhouse structures adapted in the 1960s when wider sheets of polyethylene film became widely available. Hoop houses were made by several companies and were also frequently made by the growers themselves. Constructed of aluminum extrusions, special galvanized steel tubing, or even just lengths of steel or PVC water pipe, construction costs were greatly reduced. This resulted in many more greenhouses being constructed on smaller farms and garden centers. Polyethylene film durability increased greatly when more effective UV-inhibitors were developed and added in the 1970s; these extended the usable life of the film from one or two years up to 3 and eventually 4 or more years.

Gutter-connected greenhouses became more prevalent in the 1980s and 1990s. These greenhouses have two or more bays connected by a common wall, or row of support posts. Heating inputs were reduced as the ratio of floor area to roof area was increased substantially. Gutter-connected greenhouses are now commonly used both in production and in situations where plants are grown and sold to the public as well. Gutter-connected greenhouses are commonly covered with structured polycarbonate materials, or a double layer of polyethylene film with air blown between to provide increased heating efficiency.

Build a $300 underground greenhouse for year-round gardening

Build a $300 underground greenhouse for year-round gardening (Video)

Growers in colder climates often utilize various approaches to extend the growing season or to give their crops a boost, whether it’s coldframeshoop houses or greenhouses.

Greenhouses are usually glazed structures, but are typically expensive to construct and heat throughout the winter. A much more affordable and effective alternative to glass greenhouses is the walipini (an Aymara Indian word for a “place of warmth”), also known as an underground or pit greenhouse. First developed over 20 years ago for the cold mountainous regions of South America, this method allows growers to maintain a productive garden year-round, even in the coldest of climates.

Here’s a video tour of a walipini that even incorporates a bit of interior space for goats:

It’s a pretty intriguing set-up that combines the principles of passive solar heating with earth-sheltered building. But how to make one?From American sustainable agriculture non-profit Benson Institute comes this enlightening manual on how a walipini works, and how to build it:

The Walipini utilizes nature’s resources to provide a warm, stable, well-lit environment for year-round vegetable production. Locating the growing area 6’- 8’ underground and capturing and storing daytime solar radiation are the most important principles in building a successful Walipini.

The Walipini, in simplest terms, is a rectangular hole in the ground 6 ‛ to 8’ deep covered by plastic sheeting. The longest area of the rectangle faces the winter sun — to the north in the Southern Hemisphere and to the south in the Northern Hemisphere. A thick wall of rammed earth at the back of the building and a much lower wall at the front provide the needed angle for the plastic sheet roof. This roof seals the hole, provides an insulating airspace between the two layers of plastic (a sheet on the top and another on the bottom of the roof/poles) and allows the sun’s rays to penetrate creating a warm, stable environment for plant growth.


SilverThunder/via

This earth-sheltered greenhouse taps into the thermal mass of the earth, so that much less energy is needed to heat up the walipini’s interior than an aboveground greenhouse. Of course, there are precautions to take in waterproofing, drainage and ventilating the walipini, while aligning it properly to the sun — which the manual covers in detail.

Best of all, according to the Benson Institute, their 20-foot by 74-foot walipnifield model out in La Paz cost around $250 to $300 only, thanks to the use of free labour provided by owners and neighbours, and the use of cheaper materials like plastic ultraviolet (UV) protective sheeting and PVC piping.

Cheap but effective, the underground greenhouse is a great way for growers to produce food year-round in colder climates. More over at the Benson Instituteand the Pure Energy Systems Wiki.

Land Use

http://www.mah.gov.on.ca/Page9243.aspx#introduction

http://www.mah.gov.on.ca/AssetFactory.aspx?did=8605

http://www.mah.gov.on.ca/AssetFactory.aspx?did=5926

The Crown Land Use Policy Atlas

Area in Ontario covered by the Crown Land Use Policy Atlas

The Crown Land Use Policy Atlas (the Atlas) is the source of area-specific land use policy for Crown lands in a large part of central and northern Ontario. The area covered by the Atlas (area in yellow on inset map) includes more than 39 million hectares of Crown land and waters or about 45 per cent of the province. In time, the Atlas will be expanded to include southern Ontario and the community based land use plans in the Far North.

 

The Atlas contains land use policies consolidated from a variety of planning documents such as District Land Use Guidelines (1983 as revised); local land use area plans; Ontario’s Living Legacy Land Use Strategy (1999) and the Guide to Crown Land Use Planning (2011).

 

The Atlas has three components:

If you’re a hiker, camper, bird-watcher, angler or hunter, Ontario’s natural resources provide a wealth of opportunities for activities of all kinds.

Because of the limitations of mapping data, the Atlas cannot be used to precisely identify on-the-ground locations of features such as privately-owned land, roads or other locations. Some Crown land use designations may appear to overlap onto private and federal land. These designations do not apply to such lands.

 

Radiant Barriers

Radiant barriers are installed in homes — usually in attics — primarily to reduce summer heat gain and reduce cooling costs. The barriers consist of a highly reflective material that reflects radiant heat rather than absorbing it. They don’t, however, reduce heat conduction like thermal insulation materials.

HOW THEY WORK

Heat travels from a warm area to a cool area by a combination of conduction, convection, and radiation. Heat flows by conduction from a hotter location within a material or assembly to a colder location, like the way a spoon placed in a hot cup of coffee conducts heat through its handle to your hand. Heat transfer by convection occurs when a liquid or gas — air, for example — is heated, becomes less dense, and rises. As the liquid or gas cools, it becomes denser and falls. Radiant heat travels in a straight line away from any surface and heats anything solid that absorbs its energy.

Most common insulation materials work by slowing conductive heat flow and — to a lesser extent — convective heat flow. Radiant barriers and reflective insulation systems work by reducing radiant heat gain. To be effective, the reflective surface must face an air space. Dust accumulation on the reflective surface will reduce its reflective capability. The radiant barrier should be installed in a manner to minimize dust accumulation on the reflective surface.

When the sun heats a roof, it’s primarily the sun’s radiant energy that makes the roof hot. Much of this heat travels by conduction through the roofing materials to the attic side of the roof. The hot roof material then radiates its gained heat energy onto the cooler attic surfaces, including the air ducts and the attic floor. A radiant barrier reduces the radiant heat transfer from the underside of the roof to the other surfaces in the attic.

A radiant barrier works best when it is perpendicular to the radiant energy striking it. Also, the greater the temperature difference between the sides of the radiant barrier material, the greater the benefits a radiant barrier can offer.

Radiant barriers are more effective in hot climates than in cool climates, especially when cooling air ducts are located in the attic. Some studies show that radiant barriers can reduce cooling costs 5% to 10% when used in a warm, sunny climate. The reduced heat gain may even allow for a smaller air conditioning system. In cool climates, however, it’s usually more cost-effective to install more thermal insulation than to add a radiant barrier.

TYPES OF RADIANT BARRIERS

Radiant barriers consist of a highly reflective material, usually aluminum foil, which is applied to one or both sides of a number of substrate materials such as kraft paper, plastic films, cardboard, oriented strand board, and air infiltration barrier material. Some products are fiber-reinforced to increase durability and ease of handling.

Radiant barriers can be combined with many types of insulation materials in reflective insulation systems. In these combinations, radiant barriers can act as the thermal insulation’sfacing material.

INSTALLATION

A radiant barrier’s effectiveness depends on proper installation, so it’s best to use a certified installer. If you choose to do the installation yourself, carefully study and follow the manufacturer’s instructions and safety precautions and check your local building and fire codes. The reflective insulation trade association also offers installation tips.

It’s easier to incorporate radiant barriers into a new home, but you can also install them in an existing home, especially if it has an open attic. In a new house, an installer typically drapes a rolled-foil radiant barrier foil-face down between the roof rafters to minimize dust accumulation on the reflective faces (double-faced radiant barriers are available). This is generally done just before the roof sheathing goes on, but can be done afterwards from inside the attic by stapling the material to the bottom of the rafters.

When installing a foil-type barrier, it’s important to allow the material to “droop” between the attachment points to make at least a 1.0 inch (2.5 cm) air space between it and the bottom of the roof. Foil-faced plywood or oriented strand board sheathing is also available.

Note that reflective foil will conduct electricity, so workers and homeowners must avoid making contact with bare electrical wiring. If installed on top of attic floor insulation, the foil will be susceptible to dust accumulation and may trap moisture in fiber insulation, so it is strongly recommended that you NOT apply radiant barriers directly on top of the attic floor insulation.

LEARN MORE

Insulation

HOW INSULATION WORKS

To understand how insulation works it helps to understand heat flow, which involves three basic mechanisms — conduction, convection, and radiation. Conduction is the way heat moves through materials, such as when a spoon placed in a hot cup of coffee conducts heat through its handle to your hand. Convection is the way heat circulates through liquids and gases, and is why lighter, warmer air rises, and cooler, denser air sinks in your home. Radiant heat travels in a straight line and heats anything solid in its path that absorbs its energy.

Most common insulation materials work by slowing conductive heat flow and — to a lesser extent — convective heat flow. Radiant barriers and reflective insulation systems work by reducing radiant heat gain. To be effective, the reflective surface must face an air space.

Regardless of the mechanism, heat flows from warmer to cooler until there is no longer a temperature difference. In your home, this means that in winter, heat flows directly from all heated living spaces to adjacent unheated attics, garages, basements, and even to the outdoors. Heat flow can also move indirectly through interior ceilings, walls, and floors — wherever there is a difference in temperature. During the cooling season, heat flows from the outdoors to the interior of a house.

To maintain comfort, the heat lost in the winter must be replaced by your heating system and the heat gained in the summer must be removed by your cooling system. Properly insulating your home will decrease this heat flow by providing an effective resistance to the flow of heat.

R-VALUES

An insulating material’s resistance to conductive heat flow is measured or rated in terms of its thermal resistance or R-value — the higher the R-value, the greater the insulating effectiveness. The R-value depends on the type of insulation, its thickness, and its density. When calculating the R-value of a multilayered installation, add the R-values of the individual layers. Installing more insulation in your home increases the R-value and the resistance to heat flow. To determine how much insulation you need for your climate, use an insulation calculator or consult a local insulation contractor.

The effectiveness of an insulation material’s resistance to heat flow also depends on how and where the insulation is installed. For example, insulation that is compressed will not provide its full rated R-value. The overall R-value of a wall or ceiling will be somewhat different from the R-value of the insulation itself because heat flows more readily through studs, joists, and other building materials, in a phenomenon known as thermal bridging. In addition, insulation that fills building cavities densely enough to reduce airflow can also reduce convective heat loss.

Unlike traditional insulation materials, radiant barriers are highly reflective materials that re-emit radiant heat rather than absorbing it, reducing cooling loads. As such, a radiant barrier has no inherent R-value. Although it is possible to calculate an R-value for a specific radiant barrier or reflective insulation installation, the effectiveness of these systems lies in their ability to reduce heat gain by reflecting heat away from the living space.

The amount of insulation or R-value you’ll need depends on your climate, type of heating and cooling system, and the part of the house you plan to insulate. To learn more, see our information on adding insulation to an existing house or insulating a new house. Also, remember that air sealing and moisture control are important to home energy efficiency, health, and comfort.

TYPES OF INSULATION

To choose the best insulation for your home from the many types of insulation on the market, you’ll need to know where you want or need to install the insulation, and what R-value you want the installation to achieve. Other considerations may include indoor air quality impacts, life cycle costs, recycled content, embodied energy, and ease of installation, especially if you plan to do the installation yourself. Some insulation strategies require professional installation, while homeowners can easily handle others.

INSULATION MATERIALS

Insulation materials run the gamut from bulky fiber materials such as fiberglass, rock and slag wool, cellulose, and natural fibers to rigid foam boards to sleek foils. Bulky materials resist conductive and — to a lesser degree — convective heat flow in a building cavity. Rigid foam boards trap air or another gas to resist conductive heat flow. Highly reflective foils in radiant barriers and reflective insulation systems reflect radiant heat away from living spaces, making them particularly useful in cooling climates. Other less common materials such as cementitious and phenolic foams and vermiculite and perlite are also available.

LEARN MORE

Insulation Materials

Insulation materials run the gamut from bulky fiber materials such as fiberglass, rock and slag wool, cellulose, and natural fibers to rigid foam boards to sleek foils. Bulky materials resist conductive and — to a lesser degree — convective heat flow in a building cavity. Rigid foam boards trap air or another gas to resist conductive heat flow. Highly reflective foils in radiant barriers and reflective insulation systems reflect radiant heat away from living spaces, making them particularly useful in cooling climates. Other less common materials such as cementitious and phenolic foams and vermiculite and perlite are also available.

FIBERGLASS

Fiberglass (or fiber glass) — which consists of extremely fine glass fibers — is one of the most ubiquitous insulation materials. It’s commonly used in two different types of insulation: blanket (batts and rolls) and loose-fill and is also available as rigid boards and duct insulation.

Manufacturers now produce medium- and high-density fiberglass batt insulation products that have slightly higher R-values than the standard batts. The denser products are intended for insulating areas with limited cavity space, such as cathedral ceilings.

High-density fiberglass batts for a 2 by 4 inch (51 by 102 millimeter [mm]) stud-framed wall has an R-15 value, compared to R-11 for “low density” types. A medium-density batt offers R-13 for the same space. High-density batts for a 2 by 6 inch (51 by 152 mm) frame wall offer R-21, and high-density batts for an 8.5-inch (216-mm) spaces yield about an R-30 value. R-38 batts for 12-inch (304-mm) spaces are also available.

One unconventional fibrous insulation product combines two types of glass, which are fused together.

As the two materials cool during manufacturing, they form random curls of material. This material may be less irritating and possibly safer to work with. It also requires no chemical binder to hold the batts together, and even comes in a perforated plastic sleeve to assist in handling.

Fiberglass loose-fill insulation is made from molten glass that is spun or blown into fibers. Most manufacturers use 20% to 30% recycled glass content. Loose-fill insulation must be applied using an insulation-blowing machine in either open-blow applications (such as attic spaces) or closed-cavity applications (such as those found inside walls or covered attic floors). Learn more about where to insulate.

One variation of fiberglass loose-fill insulation is the Blow-In-Blanket System® (BIBS). BIBS is blown in dry, and tests have shown that walls insulated with a BIBS system are significantly better filled than those insulated using other forms of fiberglass insulation such as batts.

The newer BIBS HP is an economical hybrid system that combines BIBS with spray polyurethane foam.

MINERAL WOOL INSULATION MATERIALS

The term “mineral wool” typically refers to two types of insulation material:

  • Rock wool, a man-made material consisting of natural minerals like basalt or diabase.
  • Slag wool, a man-made material from blast furnace slag (the scum that forms on the surface of molten metal).

Mineral wool contains an average of 75% post-industrial recycled content. It doesn’t require additional chemicals to make it fire resistant, and it is commonly available as blanket (batts and rolls) and loose-fill insulation. A Canadian company produces a softer, batt-type mineral product. This product is denser, fits standard wall cavities tighter, and is somewhat less prone to air convection thermal losses than standard fiberglass batt products. Its thermal resistance is approximately R-3.7 per inch, which is comparable with sprayed cellulose insulation or high-density fiberglass batts.

CELLULOSE INSULATION MATERIAL

Cellulose insulation is made from recycled paper products, primarily newsprint, and has a very high recycled material content, generally 82% to 85%. The paper is first reduced to small pieces and then fiberized, creating a product that packs tightly into building cavities, inhibits airflow, and provides an R-value of 3.6 to 3.8 per inch.

Manufacturers add the mineral borate, sometimes blended with the less costly ammonium sulfate, to ensure fire and insect resistance. Cellulose insulation typically requires no moisture barrier and, when installed at proper densities, cannot settle in a building cavity.

Cellulose insulation is used in both new and existing homes, as loose-fill in open attic installations and dense packed in building cavities such as walls and cathedral ceilings. In existing structures, installers remove a strip of exterior siding, usually about waist high; drill a row of three inch holes, one into each stud bay, through the wall sheathing; insert a special filler tube to the top of the wall cavity; and blow the insulation into the building cavity, typically to a density of 3.5 lb per cubic foot. When installation is complete, the holes are sealed with a plug and the siding is replaced and touched up if necessary to match the wall.

In new construction, cellulose can be either damp-sprayed or installed dry behind netting. When damp sprayed, a small amount of moisture is added at the spray nozzle tip, activating natural starches in the product and causing it to adhere inside the cavity. Damp-sprayed cellulose is typically ready for wall covering within 24 hours of installation. Cellulose can also be blown dry into netting stapled over building cavities.

PLASTIC FIBER INSULATION MATERIAL

Plastic fiber insulation material is primarily made from recycled plastic milk bottles (polyethylene terephthalate or PET). The fibers are formed into batt insulation similar to high-density fiberglass.

The insulation is treated with a fire retardant so it doesn’t burn readily, but it does melt when exposed to flame.

The R-values of plastic fiber insulation vary with the batt’s density, ranging from R-3.8 per inch at 1.0 lb/ft3 density to R-4.3 per inch at 3.0 lb/ft3 density. Plastic fiber insulation is relatively non-irritating to work with, but the batts reportedly can be difficult to handle and cut with standard tools. In many areas of the United States, plastic fiber insulation might not be readily available.

NATURAL FIBER INSULATION MATERIALS

Some natural fibers — including cotton, sheep’s wool, straw, and hemp — are used as insulation materials.

COTTON

Cotton insulation consists of 85% recycled cotton and 15% plastic fibers that have been treated with borate — the same flame retardant and insect/rodent repellent used in cellulose insulation. One product uses recycled blue jean manufacturing trim waste. As a result of its recycled content, this product uses minimal energy to manufacture. Cotton insulation is available in batts with an R-value of R-3.4 per inch. Cotton insulation is also nontoxic, and you can install it without using respiratory or skin exposure protection. However, cotton insulation costs about 15% to 20% more than fiberglass batt insulation.

SHEEP’S WOOL

For use as insulation, sheep’s wool is also treated with borate to resist pests, fire, and mold. It can hold large quantities of water, which is an advantage for use in some walls, but repeated wetting and drying can leach out the borate. The thermal resistance or R-value of sheep’s wool batts is about R-3.5 per inch, similar to other fibrous insulation types.

STRAW

Straw bale construction, popular 150 years ago on the Great Plains of the United States, has received renewed interest. Straw bales tested by Oak Ridge National Laboratory yielded R-values of R-2.4 to R-3.0 per inch. But at least one straw bale expert claims R-2.4 per inch is more representative of typical straw bale construction due to the many gaps between the stacked bales.

The process of fusing straw into boards without adhesives was developed in the 1930s. Panels are usually 2 to 4 inches (5 to 102 mm) thick and faced with heavyweight kraft paper on each side. Although manufacturers claims vary, R-values realistically range from about R-1.4 to R-2 per inch. The boards also make effective sound-absorbing panels for interior partitions. Some manufacturers have developed structural insulated panels from multiple-layered, compressed-straw panels.

HEMP

Hemp insulation is relatively unknown and not commonly used in the United States. Its R-value (about R-3.5 per inch of thickness) is similar to other fibrous insulation types.

POLYSTYRENE INSULATION MATERIALS

Polystyrene — a colorless, transparent thermoplastic — is commonly used to make foam board or beadboard insulation, concrete block insulation, and a type of loose-fill insulation consisting of small beads of polystyrene.

Molded expanded polystyrene (MEPS), commonly used for foam board insulation, is also available as small foam beads. These beads can be used as a pouring insulation for concrete blocks or other hollow wall cavities, but they are extremely lightweight, take a static electric charge very easily, and are notoriously difficult to control.

Other polystyrene insulation materials similar to MEPS are expanded polystyrene (EPS) and extruded polystyrene (XPS). EPS and XPS are both made from polystyrene, but EPS is composed of small plastic beads that are fused together and XPS begins as a molten material that is pressed out of a form into sheets. XPS is most commonly used as foam board insulation. EPS is commonly produced in blocks. Both MEPS and XPS are often used as the insulation for structural insulating panels (SIPs) and insulating concrete forms (ICFs). Learn more about different types of insulation.

The thermal resistance or R-value of polystyrene foam board depends on its density, and ranges from R-3.8 to R-5.0 per inch. Polystyrene loose-fill or bead insulation typically has a lower R-value (around R-2.3 per inch) compared to the foam board.

POLYISOCYANURATE INSULATION MATERIALS

Polyisocyanurate or polyiso is a thermosetting type of plastic, closed-cell foam that contains a low-conductivity, hydrochlorofluorocarbon-free gas in its cells. The high thermal resistance of the gas gives polyisocyanurate insulation materials an R-value ranging from R-5.6 to R-8 per inch.

Polyisocyanurate insulation is available as a liquid, sprayed foam, and rigid foam board. It can also be made into laminated insulation panels with a variety of facings. Foamed-in-place applications of polyisocyanurate insulation are usually cheaper than installing foam boards, and perform better because the liquid foam molds itself to all of the surfaces.

Over time, the R-value of polyisocyanurate insulation can drop as some of the low-conductivity gas escapes and air replaces it — a phenomenon is known as thermal drift. Experimental data indicates that most thermal drift occurs within the first two years after the insulation material is manufactured. For example, if the insulation has an initial R-value of R-9 per inch, it will likely drop to R-7 per inch, then remain unchanged unless the foam is damaged.

Foil and plastic facings on rigid polyisocyanurate foam panels can help stabilize the R-value. Testing suggests that the stabilized R-value of rigid foam with metal foil facings remains unchanged after 10 years. Reflective foil, if installed correctly and facing an open air space, can also act as a radiant barrier. Depending upon the size and orientation of the air space, this can add another R-2 to the overall thermal resistance. Panels with foil facings have stabilized R-values of R-7.1 to R-8.7 per inch.

Some manufacturers use polyisocyanurate as the insulating material in structural insulated panels (SIPs). Foam board or liquid foam can be used to manufacture a SIP. Liquid foam can be injected between two wood skins under considerable pressure, and, when hardened, the foam produces a strong bond between the foam and the skins. Wall panels made of polyisocyanurate are typically 3.5 (89 mm) thick. Ceiling panels are up to 7.5 inches (190 mm) thick. These panels, although more expensive, are more fire and water vapor-diffusion resistant than EPS. They also insulate 30% to 40% better per given thickness.

POLYURETHANE INSULATION MATERIALS

Polyurethane is a foam insulation material that contains a low-conductivity gas in its cells. The high thermal resistance of the gas gives polyurethane insulation materials an R-value ranging from R-5.5 to R-6.5 per inch.

Polyurethane foam insulation is available in closed-cell and open-cell formulas. With closed-cell foam, the high-density cells are closed and filled with a gas that helps the foam expand to fill the spaces around it. Open-cell foam cells are not as dense and are filled with air, which gives the insulation a spongy texture and a lower R-value.

Like polyiso foam, the R-value of closed-cell polyurethane insulation can drop over time as some of the low-conductivity gas escapes and air replaces it in a phenomenon known as thermal drift. Most thermal drift occurs within the first two years after the insulation material is manufactured, after which the R-value remains unchanged unless the foam is damaged.

Foil and plastic facings on rigid polyurethane foam panels can help stabilize the R-value, slowing down thermal drift. Reflective foil, if installed correctly and facing an open air space, can also act as a radiant barrier. Depending upon the size and orientation of the air space, this can add another R-2 to the overall thermal resistance. Panels with foil facings have stabilized R-values of about R-6.5 per inch.

Polyurethane insulation is available as a liquid sprayed foam and rigid foam board. It can also be made into laminated insulation panels with a variety of facings. Learn more about different types of insulation.

Sprayed or foamed-in-place applications of polyurethane insulation are usually cheaper than installing foam boards, and these applications usually perform better because the liquid foam molds itself to all of the surfaces. All closed-cell polyurethane foam insulation made today is produced with a non-HCFC (hydrochlorofluorocarbon) gas as the foaming agent.

Low-density, open-cell polyurethane foams use air as the blowing agent and about an R-3.6 per inch which doesn’t change over time. These foams are similar to conventional polyurethane foams, but are more flexible. Some low-density varieties use carbon dioxide (CO2) as the foaming agent.

Low-density foams are sprayed into open wall cavities and rapidly expand to seal and fill the cavity. Slow expanding foam is also available, which is intended for cavities in existing homes. The liquid foam expands very slowly, reducing the chance of damaging the wall from overexpansion. The foam is water vapor permeable, remains flexible, and is resistant to wicking of moisture. It provides good air sealing and yields about R-3.6 per inch of thickness. It is also fire resistant and won’t sustain a flame.

Soy-based, polyurethane liquid spray-foam products are also available. The cured R-value is about R-3.5 per inch. These products can be applied with the same equipment used for petroleum-based polyurethane foam products.

Some manufacturers use polyurethane as the insulating material in structural insulated panels (SIPs). Foam board or liquid foam can be used to manufacture a SIP. Liquid foam can be injected between two wood skins under considerable pressure, and, when hardened, the foam produces a strong bond between the foam and the skins. Wall panels made of polyurethane are typically 3.5 (89 mm) thick. Ceiling panels are up to 7.5 inches (190 mm) thick. These panels, although more expensive, are more fire and water vapor-diffusion resistant than EPS. They also insulate 30% to 40% better per given thickness.

VERMICULITE AND PERLITE INSULATION MATERIALS

Vermiculite and perlite insulation materials are commonly found as attic insulation in homes built before 1950. Vermiculite insulation materials aren’t widely used today because they sometimes contain asbestos. However, according to the U.S. Environmental Protection Agency, asbestos is not intrinsic to vermiculite. Only a few sources of vermiculite have been found to contain more than tiny trace amounts. Still, if you have vermiculite insulation in your attic, do not disturb it. If you want to add insulation to your attic, use an insulation contractor who is trained and certified in handling asbestos.

Vermiculite and perlite consist of very small, lightweight pellets, which are made by heating rock pellets until they pop. This creates a type of loose-fill insulation with a thermal resistance of up to R-2.4 per inch. These pellets can be poured into place or mixed with cement to create a lightweight, less heat-conductive concrete.

UREA-FORMALDEHYDE FOAM INSULATION MATERIAL

Urea-formaldehyde (UF) foam was used in homes during the 1970s and early 1980s. However, after many health-related court cases due to improper installations, UF foam is no longer available for residential use and has been discredited for its formaldehyde emissions and shrinkage. It is now used primarily for masonry walls in commercial and industrial buildings.

UF foam insulation has an R-value of about 4.6 per inch, and uses compressed air as the foaming agent. Nitrogen-based UF foam may take several weeks to cure completely. Unlikepolyurethane insulation, UF foam doesn’t expand as it cures. Water vapor can easily pass through it, and it breaks down at prolonged temperatures above 190°F (88°C). UF foam contains no fire retardant.

CEMENTITIOUS FOAM INSULATION MATERIAL

Cementitious insulation material is a cement-based foam used as sprayed-foam or foamed-in-placed insulation. One type of cementitious spray foam insulation known as air krete® contains magnesium silicate and has an R-value of about 3.9 per inch. With an initial consistency similar to shaving cream, air krete® is pumped into closed cavities. Cementitious foam costs about as much as polyurethane foam, is nontoxic and nonflammable, and is made from minerals (like magnesium oxide) extracted from seawater.

PHENOLIC FOAM INSULATION MATERIAL

Phenolic (phenol-formaldehyde) foam was somewhat popular years ago as rigid foam board insulation. It is currently available only as a foamed-in-place insulation.

Phenolic foamed-in-place insulation has a R-4.8 value per inch of thickness and uses air as the foaming agent. One major disadvantage of phenolic foam is that it can shrink up to 2% after curing, which makes it less popular today.

INSULATION FACINGS

Facings are fastened to insulation materials during the manufacturing process. A facing protects the insulation’s surface, holds the insulation together, and facilitates fastening to building components. Some types of facing can also act as an air barrierradiant barrier, and/orvapor barrier and some even provide flame resistance.

Common facing materials include kraft paper, white vinyl sheeting, and aluminum foil. All of these materials act as an air barrier and vapor barrier. Aluminum foil can also act as a radiant barrier. Your climate and where and how you’re installing the insulation in your home will determine what type of facing and/or barrier, if any, you’ll need.

Some of the same materials used as insulation facings can be installed separately to provide an air barrier, vapor barrier, and/or radiant barrier.

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Insulation Types

When insulating your home, you can choose from many types of insulation. To choose the best type of insulation, you should first determine the following:

  • Where you want or need to install/add insulation
  • The recommended R-values for areas you want to insulate.

INSTALLING INSULATION

The maximum thermal performance or R-value of insulation is very dependent on proper installation. Homeowners can install some types of insulation — notably blankets and materials that can be poured in place. Other types require professional installation.

When hiring a professional certified installer:

  • Obtain written cost estimates from several contractors for the R-value you need, and don’t be surprised if quoted prices for a given R-value installation vary by more than a factor of two.
  • Ask contractors about their air-sealing services and costs as well, because it’s a good idea to seal air leaks before installing insulation.

To evaluate blanket installation, you can measure batt thickness and check for gaps between batts as well as between batts and framing. In addition, inspect insulation for a tight fit around building components that penetrate the insulation, such as electrical boxes. To evaluate sprayed or blown-in types of insulation, measure the depth of the insulation and check for gaps in coverage.

If you choose to install the insulation yourself, follow the manufacturer’s instructions and safety precautions carefully and check local building and fire codes. Do-it-yourself instructions are available from the fiberglass and mineral wool trade group. The cellulose trade grouprecommends hiring a professional, but if there isn’t a qualified installer in your area or you feel comfortable taking on the job, you may be able to find guidance from manufacturers.

The table below provides an overview of most available insulation materials, how they are installed, where they’re typically installed, and their advantages.

Types of Insulation

Type Insulation Materials Where Applicable Installation Method(s) Advantages
Blanket: batts and rolls •Fiberglass•Mineral (rock or slag) wool•Plastic fibers

•Natural fibers

•Unfinished walls, including foundation walls•Floors and ceilings Fitted between studs, joists, and beams. Do-it-yourself.Suited for standard stud and joist spacing that is relatively free from obstructions. Relatively inexpensive.
Concrete block insulationand insulating concrete blocks Foam board, to be placed on outside of wall (usually new construction) or inside of wall (existing homes):Some manufacturers incorporate foam beads or air into the concrete mix to increase R-values •Unfinished walls, including foundation walls,for new construction or major renovations•Walls (insulating concrete blocks) Require specialized skillsInsulating concrete blocks are sometimes stacked without mortar (dry-stacked) and surface bonded. Insulating cores increases wall R-value.Insulating outside of concrete block wall places mass inside conditioned space, which can moderate indoor temperatures.Autoclaved aerated concrete and autoclaved cellular concrete masonry units have 10 times the insulating value of conventional concrete.
Foam board or rigid foam •Polystyrene•Polyisocyanurate•Polyurethane •Unfinished walls, including foundation walls•Floors and ceilings•Unvented low-slope roofs Interior applications: must be covered with 1/2-inch gypsum board or other building-code approved material for fire safety.Exterior applications: must be covered with weatherproof facing. High insulating value for relatively little thickness.Can block thermal short circuits when installed continuously over frames or joists.
Insulating concrete forms (ICFs) •Foam boards or foam blocks •Unfinished walls, including foundation walls for new construction Installed as part of the building structure. Insulation is literally built into the home’s walls, creating high thermal resistance.
Loose-fill and blown-in •Cellulose•Fiberglass•Mineral (rock or slag) wool

 

•Enclosed existing wall or open new wall cavities•Unfinished attic floors•Other hard-to-reach places Blown into place using special equipment, sometimes poured in. Good for adding insulation to existing finished areas, irregularly shaped areas, and around obstructions.
Reflective system •Foil-faced kraft paper, plastic film, polyethylene bubbles, or cardboard •Unfinished walls, ceilings, and floors Foils, films, or papers fitted between wood-frame studs, joists, rafters, and beams. Do-it-yourself.Suitable for framing at standard spacing.Bubble-form suitable if framing is irregular or if obstructions are present.

Most effective at preventing downward heat flow, effectiveness depends on spacing.

Rigid fibrous or fiber insulation •Fiberglass•Mineral (rock or slag) wool •Ducts in unconditioned spaces•Other places requiring insulation that can withstand high temperatures HVAC contractors fabricate the insulation into ducts either at their shops or at the job sites. Can withstand high temperatures.
Sprayed foam and foamed-in-place •Cementitious•Phenolic•Polyisocyanurate

•Polyurethane

•Enclosed existing wall•Open new wall cavities•Unfinished attic floors Applied using small spray containers or in larger quantities as a pressure sprayed (foamed-in-place) product. Good for adding insulation to existing finished areas, irregularly shaped areas, and around obstructions.
Structural insulated panels (SIPs) •Foam board or liquid foam insulation core•Straw core insulation •Unfinished walls, ceilings, floors, and roofs for new construction Construction workers fit SIPs together to form walls and roof of a house. SIP-built houses provide superior and uniform insulation compared to more traditional construction methods; they also take less time to build.

BLANKET: BATT AND ROLL INSULATION

Blanket insulation — the most common and widely available type of insulation — comes in the form of batts or rolls. It consists of flexible fibers, most commonly fiberglass. You also can find batts and rolls made from mineral (rock and slag) wool, plastic fibers, and natural fibers, such as cotton and sheep’s wool. Learn more about these insulation materials.

Batts and rolls are available in widths suited to standard spacing of wall studs, attic trusses or rafters, and floor joists. Continuous rolls can be hand-cut and trimmed to fit. They are available with or without facings. Manufacturers often attach a facing (such as kraft paper, foil-kraft paper, or vinyl) to act as a vapor barrier and/or air barrier. Batts with a special flame-resistant facing are available in various widths for basement walls and other places where the insulation will be left exposed. A facing also helps facilitate fastening during installation. However, unfaced batts are a better choice when adding insulation over existing insulation.

Standard fiberglass blankets and batts have a thermal resistance or R-value between R-2.9 and R-3.8 per inch of thickness. High-performance (medium-density and high-density) fiberglass blankets and batts have R-values between R-3.7 and R-4.3 per inch of thickness. See the table below for an overview of these characteristics.

FIBERGLASS BATT INSULATION CHARACTERISTICS

This table is for comparison of fiberglass batts only. Determine actual thickness, R-value, and cost from manufacturer and/or local building supplier.

Thickness (inches) R-Value Cost (cents/sq. ft.)
3 1/2 11 12-16
3 5/8 13 15-20
3 1/2 (high density) 15 34-40
6 to 6 1/4 19 27-34
5 1/4 (high density) 21 33-39
8 to 8 1/2 25 37-45
8 (high density) 30 45-49
9 1/2 (standard) 30 39-43
12 38 55-60

CONCRETE BLOCK INSULATION

Concrete blocks are used to build home foundations and walls, and there are several ways to insulate them. If the cores aren’t filled with steel and concrete for structural reasons, they can be filled with insulation, which raises the average wall R-value. Field studies and computer simulations have shown, however, that core filling of any type offers little fuel savings, because heat is readily conducted through the solid parts of the walls such as block webs and mortar joints.

It is more effective to install insulation over the surface of the blocks either on the exterior or interior of the foundation walls. Placing insulation on the exterior has the added advantage of containing the thermal mass of the blocks within the conditioned space, which can moderate indoor temperatures.

Some manufacturers incorporate polystyrene beads into concrete blocks, and surface-bonded assemblies of these units have wall R-values of R-1 per inch. Other manufacturers make concrete blocks that accommodate rigid foam inserts that increase the unit thermal resistance to about R-2 per inch.

In the United States, two varieties of solid, precast autoclaved concrete masonry units are now available: autoclaved aerated concrete (AAC) and autoclaved cellular concrete (ACC). This material contains about 80% air by volume and has been commonly used in Europe since the late 1940s. Autoclaved concrete has ten times the insulating value of conventional concrete. The R-1.1 per inch blocks are large, light, and easily sawed, nailed, and shaped with ordinary tools. The material absorbs water readily, so it requires protection from moisture. Precast ACC uses fly ash instead of high-silica sand, which distinguishes it from AAC. Fly ash is a waste ash produced from burning coal in electric power plants.

Hollow-core units made with a mix of concrete and wood chips are also available. They are installed by stacking the units without using mortar (dry-stacking) and filling the cores with concrete and structural steel. One potential problem with this type of unit is that the wood is subject to the effects of moisture and insects.

Concrete block walls are typically insulated or built with insulating concrete blocks during new home construction or major renovations. Block walls in existing homes can be insulated from the inside. Go to insulation materials for more information about the products commonly used to insulate concrete block.

FOAM BOARD OR RIGID FOAM

Foam boards — rigid panels of insulation — can be used to insulate almost any part of your home, from the roof down to the foundation. They provide good thermal resistance, and reduce heat conduction through structural elements, like wood and steel studs. The most common types of materials used in making foam board include polystyrene, polyisocyanurate (polyiso), and polyurethane.

INSULATING CONCRETE FORMS

Insulating concrete forms (ICFs) are basically forms for poured concrete walls, which remain as part of the wall assembly. This system creates walls with a high thermal resistance, typically about R-20. Even though ICF homes are constructed using concrete, they look like traditional stick-built homes.

ICF systems consist of interconnected foam boards or interlocking, hollow-core foam insulation blocks. Foam boards are fastened together using plastic ties. Along with the foam boards, steel rods (rebar) can be added for reinforcement before the concrete is poured. When using foam blocks, steel rods are often used inside the hollow cores to strengthen the walls.

The foam webbing around the concrete-filled cores of blocks can provide easy access for insects and groundwater. To help prevent these problems, some manufacturers make insecticide-treated foam blocks and promote methods for waterproofing them. Installing an ICF system requires an experienced contractor, available through the Insulating Concrete Form Association.

LOOSE-FILL AND BLOWN-IN INSULATION

Loose-fill insulation consists of small particles of fiber, foam, or other materials. These small particles form an insulation material that can conform to any space without disturbing structures or finishes. This ability to conform makes loose-fill insulation well suited for retrofits and locations where it would be difficult to install other types of insulation.

The most common types of materials used for loose-fill insulation include cellulose, fiberglass, and mineral (rock or slag) wool. All of these materials are produced using recycled waste materials. Cellulose is primarily made from recycled newsprint. Most fiberglass contains 20% to 30% recycled glass. Mineral wool is usually produced from 75% post-industrial recycled content. The table below compares these three materials.

Recommended Specifications by Loose-Fill Insulation Material

Cellulose Fiberglass Rock Wool
R-value/inch 3.2–3.8 2.2–2.7 3.0–3.3
Inches (cm) needed for R-38 10–12 (25–30) 14–17 (35–43) 11.5–13 (29–33)
Density in lb/ft3 (kg/m3) 1.5–2.0 (24–36) 0.5–1.0 (10–14) 1.7 (27)
Weight at R-38 in lb/ft2 (kg/m2) 1.25–2.0 (6–10) 0.5–1.2 (3–6) 1.6–1.8 (8–9)
OK for 1/2″ drywall, 24″ on center? No Yes No
OK for 1/2″ drywall, 16″ on center? Yes Yes Yes
OK for 5/8″ drywall, 24″ on center? Yes Yes Yes

Some less common loose-fill insulation materials include polystyrene beads and vermiculite and perlite. Loose-fill insulation can be installed in either enclosed cavities such as walls, or unenclosed spaces such as attics. Cellulose, fiberglass, and rock wool are typically blown in by experienced installers skilled at achieving the correct density and R-values. Polystyrene beads, vermiculite, and perlite are typically poured.

RADIANT BARRIERS AND REFLECTIVE INSULATION SYSTEMS

Unlike most common insulation systems, which resist conductive and sometimes convective heat flow, radiant barriers and reflective insulation work by reflecting radiant heat away from the living space. Radiant barriers are installed in homes — usually in attics — primarily to reduce summer heat gain, which helps lower cooling costs. Reflective insulation incorporates radiant barriers — typically highly reflective aluminum foils — into insulation systems that can include a variety of backings, such as kraft paper, plastic film, polyethylene bubbles, or cardboard, as well as thermal insulation materials.

Radiant heat travels in a straight line away from any surface and heats anything solid that absorbs its energy. When the sun heats a roof, it’s primarily the sun’s radiant energy that makes the roof hot. A large portion of this heat travels by conduction through the roofing materials to the attic side of the roof. The hot roof material then radiates its gained heat energy onto the cooler attic surfaces, including the air ducts and the attic floor. A radiant barrier reduces the radiant heat transfer from the underside of the roof to the other surfaces in the attic. To be effective, it must face an air space.

Radiant barriers are more effective in hot climates, especially when cooling air ducts are located in the attic. Some studies show that radiant barriers can lower cooling costs 5% to 10% when used in a warm, sunny climate. The reduced heat gain may even allow for a smaller air conditioning system. In cool climates, however, it’s usually more cost-effective to install more thermal insulation.

RIGID FIBER BOARD INSULATION

Rigid fiber or fibrous board insulation consists of either fiberglass or mineral wool material and is primarily used for insulating air ducts in homes. It is also used when there’s a need for insulation that can withstand high temperatures. These products come in a range of thicknesses from 1 inch to 2.5 inches, and provide an R-value of about R-4 per inch of thickness.

Installation in air ducts is usually done by HVAC contractors, who fabricate the insulation at their shops or at job sites. On exterior duct surfaces, they can install the insulation by impaling it on weld pins and securing with speed clips or washers. They can also use special weld pins with integral-cupped head washers. Unfaced boards can then be finished with reinforced insulating cement, canvas, or weatherproof mastic. Faced boards can be installed in the same way, and the joints between boards sealed with pressure-sensitive tape or glass fabric and mastic.

SPRAYED-FOAM AND FOAMED-IN-PLACE INSULATION

Liquid foam insulation materials can be sprayed, foamed-in-place, injected, or poured. Some installations can have twice the R-value per inch of traditional batt insulation, and can fill even the smallest cavities, creating an effective air barrier.

TYPES OF LIQUID FOAM INSULATION

Today, most foam materials use foaming agents that don’t use chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs), which are harmful to the earth’s ozone layer.

Available liquid foam insulation materials include:

  • Cementitious
  • Phenolic
  • Polyisocyanurate (polyiso)
  • Polyurethane.

Some less common types include Icynene foam and Tripolymer foam. Icynene foam can be either sprayed or injected, which makes it the most versatile. It also has good resistance to both air and water intrusion. Tripolymer foam—a water-soluble foam—is injected into wall cavities. It has excellent resistance to fire and air intrusion.

INSTALLATION

Liquid foam insulation — combined with a foaming agent — can be applied using small spray containers or in larger quantities as a pressure-sprayed (foamed-in-place) product. Both types expand and harden as the mixture cures. They also conform to the shape of the cavity, filling and sealing it thoroughly.

Slow-curing liquid foams are also available. These foams are designed to flow over obstructions before expanding and curing, and they are often used for empty wall cavities in existing buildings. There are also liquid foam materials that can be poured from a container.

Installation of most types of liquid foam insulation requires special equipment and certification and should be done by experienced installers. Following installation, an approved thermal barrier equal in fire resistance to half-inch gypsum board must cover all foam materials. Also, some building codes don’t recognize sprayed foam insulation as a vapor barrier, so installation might require an additional vapor retarder.

COSTS

Liquid foam insulation products and installation usually cost more than traditional batt insulation. However, liquid foam insulation has higher R-values and forms an air barrier, which can eliminate some of the other costs and tasks associated with weatherizing a home, such as caulking, applying housewrap and vapor barrier, and taping joints. When building a new home, this type of insulation can also help reduce construction time and the number of specialized contractors, which saves money.

STRUCTURAL INSULATED PANELS

Structural insulated panels (SIPs) are prefabricated insulated structural elements for use in building walls, ceilings, floors, and roofs. They provide superior and uniform insulation compared to more traditional construction methods (stud or “stick frame”), offering energy savings of 12% to 14%. When installed properly, SIPs also result in a more airtight dwelling, which makes a house quieter and more comfortable.

SIPs not only have high R-values but also high strength-to-weight ratios. A SIP typically consists of 4- to 8-inch-thick foam board insulation sandwiched between two sheets of oriented strand board (OSB) or other structural facing materials. Manufacturers can usually customize the exterior and interior sheathing materials to meet customer requirements. The facing is glued to the foam core, and the panel is then either pressed or placed in a vacuum to bond the sheathing and core together.

SIPs can be produced in various sizes or dimensions. Some manufacturers make panels as large as 8 by 24 feet, which require a crane to erect.

The quality of SIP manufacturing is very important to the long life and performance of the product. The panels must be glued, pressed, and cured properly to ensure that they don’t delaminate. The panels also must have smooth surfaces and edges to prevent gaps from occurring when they’re connected at the job site. Before purchasing SIPs, ask manufacturers about their quality control and testing procedures and read and compare warranties carefully. SIPs are available with different insulating materials, usually polystyrene or polyisocyanurate foam.

INSTALLATION

SIPs are made in a factory and shipped to job sites. Builders then connect them together to construct a house. For an experienced builder, a SIPs home goes up much more quickly than other homes, which saves time and money without compromising quality. These savings can help offset the usually higher cost of SIPs.

Many SIP manufacturers also offer “panelized housing kits.” The builder need only assemble the pre-cut pieces, and additional openings for doors and windows can be cut with standard tools at the construction site.

When installed according to manufacturers’ recommendations, SIPs meet all building codes and pass the American Society for Testing and Materials (ASTM) standards of safety. In buildings constructed of SIPs, fire investigators have found that the panels held up well. For example, in one case a structure fire exceeded 1,000°F (538°C) in the ceiling areas and 200°F (93°C) near the floors, and most wall panels and much of the ceiling remained intact. An examination of the wall panels revealed that the foam core had neither melted nor delaminated from the skins. In similar cases, a lack of oxygen seemingly caused the fire to extinguish itself. The air supply in an airtight SIP home can be quickly consumed in a fire.

AREAS OF CONCERN

Fire safety is a concern, but when the interior of the SIP is covered with a fire-rated material, such as gypsum board, it protects the facing and foam long enough to give building occupants a chance to escape.

As in any house, insects and rodents can be a problem. In a few cases, insects and rodents have tunneled throughout the SIPs, and some manufacturers have issued guidelines for preventing these problems, including:

  • Applying insecticides to the panels
  • Treating the ground with insecticides both before and after initial construction and backfilling
  • Maintaining indoor humidity levels below 50%
  • Locating outdoor plantings at least two feet (0.6 meters) away from the walls
  • Trimming any over-hanging tree limbs.

Boric acid-treated insulation panels are also available. These panels deter insects, but are relatively harmless to humans and pets.

Because it is so airtight, a well-built SIP structure requires controlled fresh-air ventilation for safety, health, and performance, and to meet many building codes. A well-designed, installed, and properly operated mechanical ventilation system can also help prevent indoor moisture problems, which is important for achieving the energy-saving benefits of an SIP structure.

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REFERENCES
Climate-Specific Construction Details – buildingscience.com
Green Building Information – buildinggreen.com
Insulation and Energy Efficiency Information – Home Energy: The Magazine of Residential Energy Conservation
Insulation: Thermal Performance is Just the Beginning – BuildingGreen.com