Some are more desirable than others based on the application they are used in. The effectiveness of an insulated roof system depends on whitch insulation is installed.
When selecting a roofing insulation material, building professionals typically look for a product that offers high R-value at a competitive price. Equally important is the insulation's ability to withstand exposure to real-world conditions while maintaining long-term R-value and other important performance characteristics. Polystyrene and polyisocyanurate insulation materials are affected differently by real-world conditions. So, the question becomes: Are building owners and roofing/architectural professionals getting long-term performance value from roofing insulation products? In general, foam plastic insulation products, such as expanded polystyrene (EPS), extruded polystyrene (XPS) and polyisocyanurate (polyiso) offer higher insulation values than other materials. But even something as fundamental to insulation as its R-value can vary depending on. What's an R-Value? - this is the unit used to describe thermal resistance. You may have heard of RSI values too. RSI is the metric equivalent of R-values.
When the "Energy Crisis" of the 1970 sent home heating and cooling costs soaring, demand for building insulation rose right along with the prices of oil, gas, and electricity. As often (unfortunately) happens when demand for a product increases suddenly and dramatically the promise of fast and easy profits occasionally led to fast and easy sales and marketing practices by some insulation sellers. Eventually the claims and confusion in the insulation market became so extreme the Federal Trade Commission instituted "The R-Value Rule." This regulation placed clear limitations on the claims and statements manufacturers and marketers can make about insulation products and the energy savings they may produce. The regulation is called "The R-Value Rule," because it is based on a mathematical term known to engineers as "The R-Factor." R-Factor is a measure of the ability of insulation material to resist heat transfer. It's determined by placing carefully prepared test specimens between two plates in a laboratory apparatus and measuring heat flow through the insulation. "R-Value" is the R-Factor of the insulation multiplied by the amount of the material. If insulation has an R-Factor of 3.8, and there are 3.5 inches of insulation between the warm side and the cool side of the assembly, the R-Value of the insulation in the system is 13.3.
The R-Value Rule is a good regulation that has significantly reduced misrepresentation and outright fraud in the insulation industry. It's one of the most important and successful consumer protection regulations. Consumers often assume The R-Value Rule will automatically and unerringly lead them to the insulation product that will produce the greatest energy savings when it's installed in a building. Unfortunately, this isn't the case. In the real world of buildings things are a bit more complicated. In fact, they're a lot more complicated.
R-Value is a very accurate and reliable expression of how insulation materials perform in a laboratory apparatus. But people don't live in laboratories. They live in homes with real walls and ceilings, and in the real world of buildings R-Value is only one factor in the actual performance of insulated building assemblies. For comparison purposes, rigid roofing insulation materials have been divided into groups: wood fiber, minerai fiber, glass fiber, perlite, polystyrene and phenolic.
Wood Fiber Insulation
Wood-Fiber Insulation Boards are one of the first industrially made insulation products. Despite serious competition from mineral fiber and plastic foam products today.
Why using Wood-Fiber Insulation Board:
• Wood is a sustainable raw material with not very energy intensive processing. It's ecologically sound.
• It increases living comfort. The thermal capacity of wood is much higher than that of mineral fiber or plastic foam, as result Wood-Fiber Insulation Boards protect much better against summer heat.
• It supports uniform interior climate. The thermal conductivity of Wood-Fiber Insulation Boards is not much affected by moisture which enables diffusionopen wall designs. Picked-up moisture will be released over time without problems. This type of board is made up of wood fibers, held together by a binder; the board may be impregnated and/or coated with asphalt or paraffin.
Manufacturing processes of Wood-Fiber Insulation Board are varying, but certain operations are common to all fiberboard products. The raw material is always reduced to a pulp, after which the fibers are chemically treated with waterproofing materials. Then fibers are formed into large sheets of varying thickness by a felting process. After sheets are dried, cut and trimmed to a finished size. In order to have moisture-resistant for special projects, fiberboard either impregnate with asphalt during the manufacturing process, or coat with asphalt after they are produced.
Mineral Fiber Insulation
Although the term mineral fiber historically refers to rock wool and slag wool, fiberglass products are also included in this category. These are also called man-made vitreous fibers (MMVFs), referring to the glassy, noncrystalline nature of these materials. A binding agent helps form the fibers into a rigid insulation board to be used for low-slope roofing systems. A glass-mat facer is applied to the top surface of the board. Mineral fiber insulation is compatible with bitumens and other adhesives, fire-resistant, dimensionally stable, and compatible with other roofing materials. Mineral fiber insulation is not as sensitive to moisture as fiberglass insulation because the separate mineral fibers absorb (but retain) only minimal moisture.
Mineral fiber board has a low compressive strength and is not recommended for loose-laid, ballasted roofing systems or mechanically fastened roofing membranes. Mineral Fiber Insulation is made up of inorganic fibers, non-metallic and amorphous, made from rocks, slag (metallurgical by-product) or glass, held together by a binder
Fiberglass Insulation is a rigid roof insulation board composed of heat-fused, closed glass cells blown with hydrogen sulfide. Available for low-slope roofing systems, the boards typically have kraft paper facers applied to the surfaces after the material is formed. Cellular glass is compatible with bitumen and other adhesives and is fire-resistant. The board itself is moisture-resistant, but the paper facers, to which other materials are adhered, will deteriorate if wetted. The boards are rigid and require care in handling so that they do not crack or spall. The thermal resistance of cellular glass is stable but not as high as it is for other insulation materials
Fiberglass insulation board is a slightly modified product. After bonding fiberglass into a board shape, asphalt is used to bond a kraft paper facer to the top surface of the board. The paper facer will deteriorate if wetted, and the fiberglass board will retain water, reducing the thermal value. The thermal resistance of mineral fiber is stable and has a relatively high R-value compared with other insulation materials.
Perlite Rigid Board
This type of board is made up of expanded granulated volcanic rock (perfite) and of cellulosic fibers held together by a binder. Perlite is different from other volcanic glasses because when the crushed ore is heated to a suitable point in its softening range, it expands from 4 to 20 times its original volume. Used for low-slope roofing systems, perlite insulation is manufactured as a rigid board that is composed of these expanded volcanic minerals combined with organic fibers and binders. An asphalt emulsion is used to treat the top surface to inhibit the absorption of bitumens. Perlite is compatible with bitumens and other adhesives, fire-resistant, dimensionally stable, and compatible with other roofing materials. The boards are covered with a specifie coating which prevents excessive absorption of asphalt at the time of it's application.
The board will withstand impact, but care must be taken when handling the boards because they can break easily. The thermal resistance of the insulation is stable, but it has a relatively low R-value. Typically, perlite is not used with ballasted, loose-laid membranes because the board will readily absorb moisture.
Expanded Polystyrene Roof Insulation
Expanded Polystyrene (EPS) Roof Insulation is compatible with all major roofing materials and systems, making it ideal for use in ballasted, mechanically fastened and fully adhered roofs under both membrane and built-up coverings. EPS provides permanent high R-Values, superior dimensional stability and documented resistance to moisture absorption and physical degradation. Expanded Polystyrene Insulation available in flat, tapered, and compound tapered panels. EPS provides building owners, contractors and architectural specifies the confidence that comes from its successful application in millions of square feet of high-performance roof systems.
When specifying or applying polystyrene insulation, need to be assured that each panel is manufactured and fabricated according specifications. Most of EPS roof insulation is manufactured to meet ASTM C578-01 standards and is certified for compliance. Manufactured in thicknesses up to 36 inches using state-of-the-art software, flat, tapered and compound tapered panels can offer more slope and dimension options than other insulation products, which can design a roofing system that will meet all of your insulating, load-bearing and slope requirements. Custom layouts, shop drawings and quotations for any project, large or small can be provided.
Benefits EPS Roof Insulation:
• The lowest unit cost per R-Value of any rigid insulation board provides high insulating values that will not diminish over time.
• Superior dimensional stability helps assure that your roof insulation system remains tight and energy-efficient with wide list of roofing membranes.
• Resistant to the effects of moisture, yet it breathes, is not a vapor barrier and needs no venting.
• Compressive strengths ranging from 10 - 25 psi that can accommodate specific roof traffic and loads without deforming.
• Superior design flexibility allows our flat, tapered and compound tapered panels to offer more slope and dimension options than other insulations.
Phenolic Insulation Board
This type of insulation board in both Canada and the United States declined rapidly and has not been available since 1994. Incidents of deck corrosion have been reported in cases where the insulation is in direct contact with steel roof decks and moisture is present. Phenolic foam board products were manufactured from phenol formaldehyde resin as an open- or closed-cell product. For several years, a high R-value phenolic rigid insulation board was on the market. This closed-cell insulation had a typical R-value of 8.3 per inch. Because the foam boards often shrank, warped, or decomposed, manufacturers stopped making them.
- PazRoofing assist you in designing the optimum roof system to meet your needs and budget...
Learn more »
- PAZRoofing specialists fast locate the damaged area and stop the leak at its source...
Learn more »
- We are carrie a leading role in using the innovative waterproofing products...
Learn more »