Foam board insulation is just beginning to break into the residential market. Usually the insulation of commercial buildings, rigid foam panels provide superior thermal protection in all buildings as well as to bolster the structural integrity of walls and ceilings. This is why buildings made from concrete, and those containing steel studded walls, can still maintain even temperatures as good or better than wood-framed residential homes.
The initial cost of foam board insulation is almost twice that of the traditional products like fiberglass batts and blown-in cellulose. These less expensive insulation products are the mainstay of the new home building and renovation market. Fiberglass batts are manufactured in fifteen-inch widths in order to perfectly site into walls spaces and cellulose is blown into attics and is great for insulating older homes with no insulation in the walls.
The Benefits of Foam Board Insulation
- Handling: For the same R-value as the traditional insulating materials a home needs from one-third to one-half of the thickness of foam board insulation. The foam panels are also cut to fit the fifteen-inch centres of wall studs, and the handlers do not have to wear special clothing or respirators to protect from minute, abrasive particles.
- Moisture Resistant: Both fiberglass batt and blown-in cellulose insulation have no protection against moisture that can enter the walls from a leaky window or other small spaces. Too much moisture will minimize the thermal effectiveness of the material because the air pockets will be compromised. The moisture also causes settling which can cause gaps at the top of the walls. Foam panels hold their shape when wet and protect the insulating qualities.
- Pest Barrier: Foam is rigid and does not normally allow insects or rodents to burrow into its mass like fiberglass batting and loose cellulose. This enables drafts to get into the home.
- Air Currents: Traditional forms of insulation require an expert eye to make sure that there are no gaps between the batts or along the studs. These spaces can let cold air channel through and into the home.
Foam board insulation is available in three (3) major forms:
1. MEPS (Molded Expanded Polystyrene Foam Board)
Molded expanded polystyrene, or MEPS, is a closed-cell foam used to manufacture many common items: shipping padding, coffee cups and floatation devices. When made into sheets of rigid foam boards it is referred to as "beadboard," a mixture of polystyrene beads and liquid pentane. This aggregate is poured into a mixing container and blasted with a "blowing agent." Then it is heated whereby the beads expand. Next they are injected into the mold and heated again. This time the mixture is pressurized and it takes the shape of the mold.
The types of MEPS vary with the bead densities and are based on where they are to be used. In roofing, for example, foam board has to be strong enough to walk on hence the beads are made denser. Since wall insulation is not load-bearing the beads can be manufactured in a looser configuration. Although not as strong, the R-value of this board is high, ranging from 3.8 to 4.4 per inch of thickness. A wall containing MEPS will have a better R-value than traditional insulating materials at half the thickness. Available in a variety of finishes MEPS is also used in structural insulated panels (SIPs) and insulated concrete forms (ICFs).
2. XEPS (Extruded Expanded Polystyrene Foam Board)
Extruded expanded polystyrene, or XEPS, is a closed-cell foam insulation. It is much like MEPS except it is manufactured by mixing polystyrene pellets with liquid chemicals. A blowing agent is then injected into the mixture producing a foaming froth. This liquid foam is injected into a mold or extruded through a special die to make panels.
XEPS is a more expensive way to manufacture rigid foam because its chemical base costs more. Like MEPS the density of the extruded expanded polystyrene foam board decides the R-value. In most cases the R-value is approximately R-5 per inch. The high density of XEPS makes it great for roofs and walls. The density of XEPS is greater than MEPS making it more resistant to the influx of moisture.
3. Polyisocyanurate and Polyurethane Foam Insulation
Polyisocyanurate and polyurethane are two other types of closed-cell, foam insulation that are manufactured in a different way. At R-5.6 to R-8 per inch of foam board thickness they can achieve a similar thermal resistance to thicker pane of XEPS or MEPS. This makes it almost wafer-thin compared with fiberglass batts and blown-in cellulose insulation, which is a big advantage when space is at a premium.
In addition, polyisocyanurate and polyurethane foam panels have varying compressive strengths. This helps them to maintain integrity and shape under high wind velocities or severe loads. As well, they have an amazing resistance to heat remaining stable at temperatures from -75ºCelsius up as high as +120ºCelsius.
For more information on foam board insulation consult our Contractor Directory or simply post you project online.Posted by: TrustedPros