Contractors who want to get the most out of their products are attracted to items that offer several different functions. Polyiso insulation does just that by serving several important functions in a high-performing wall system, all rolled into one product.

Continuous insulation is not new and has been in successful use for more than half of a century. It is now, however, prominently featured in newer energy codes because it is known to be a very effective way to insulate building envelopes for energy savings.

Functions

Polyiso as continuous insulation provides the ability to resist heat transfer. This creates what is known as a “thermal blanket” over the building, ultimately conserving energy and increasing occupant comfort. Other functions of a polyiso continuous insulation system include:

• Moisture vapor control: Very low perm rating that minimizes water vapor transmission passing through the foam board

• Water resistive barrier (WRB): Protection against moisture exposure

• Air barrier: Sheathing membrane that protects against air leakage through the building envelope

• Wind pressure resistance: Code-compliant for exterior wall sheathing

• Fire Test Compliant: forms a protective char layer and remains in place during fire exposure

• High R-value: greater resistance to heat flow

Benefits

Increased thermal performance

Continuous insulation systems increase the overall thermal performance of the wall assembly and building, by blocking thermal bridging (“short circuit” between the interior and exterior of a building).The image below, provided by the American Chemistry Council, illustrates this activity.

Reduced operating costs

The ability to have increased energy efficiency at reasonable first cost allows for operating cost paybacks through reduced energy bills. Rigid foam plastic sheathing materials are preferred for continuous insulation because of their relatively high R-value per inch and low cost to meet or exceed energy code requirements.

Reduced air infiltration and exfiltration

Continuous insulation with taped or sealed joints restricts air movement through the wall, helping to further reduce building heat loss.

Reduced risk of water condensation and moisture intrusion

Continuous insulation is a very moisture-resistant system, guarding the thermal and structural performance of the building. Ci helps prevent condensation from forming inside walls by keeping them warm and above dew point temperature.

Efficient installation

When used as a multi-function sheathing, continuous insulation can simplify the steps to construct a code-compliant wall assembly.

Structural Durability

Polyiso insulation has excellent dimensional stability and meets ASTM C1289 Standard Specifications. Foam plastic sheathing materials do not rot, decay, or corrode like some other building materials.

These capabilities prove polyiso ci systems to be necessary in achieving high-performance wall assemblies. Having so many functions and benefits in one product allows for polyiso continuous insulation to be used alone in order to meet energy code, without any cavity insulation for the ultimate “warm wall” design.