Polyshield® RadWrap™ foil/white, 95% reflective, perforated house wrap material has many applications. It is generally known for its superior performance as a vapor barrier, a moisture barrier, and an insulated house wrap. Polyshield® RadWrap™ consists of a highly reflective material which reflects radiant heat rather than absorbing it. Appling RadWrap™ to your sidewalls can improve the efficiency of traditional insulation by 50%, based on independent laboratory studies.
How to Increase R-Values in wall assemblies when applying RadWrap™
States & municipalities have been increasing their R-Value code requirements in sidewalls recently. The increased requirements can pose challenges, as many sidewalls are just 4” thick.
RadWrap™ is generally accepted as a Radiant Barrier which can increase R-Values in sidewalls when following specific installation methods.
Method 1: Inside Wall Application:
Install R-12 Fiberglass batting in your wall space.
Wrap the inside wall 4” studs with RadWrap™, with the silver side facing the insulation, covering the insulation, and adding 1” of dead airspace. Then, install your Drywall Board directly to the studs as usual. This installation method provides an R-Value of R-17 without taking into consideration the R-Values of the drywall or the Exterior Wall (such as brick or siding), which could add another R-2 or more to the application.
Method 2: Outside Wall Application:
Simply wrap the RadWrap™, silver side out, to the outside wall, directly attaching to the OSB as you would a traditional house wrap. If the exterior wall is brick, there will be an additional 1” or 2” of airspace in between the OSB and the bricks. If the exterior wall is a plank siding that traditionally installs directly to the OSB, it will be necessary to add 1” spacers or furring strips in between the OSB and the plank siding to create an additional airspace.
This 1” of addition airspace will increase the R-Value by R-5. Install R-13 Fiberglass Batting as usual. This installation method provides a 95% reflectivity and a R-18 without taking into consideration the R-Values of the other building materials in the wall assembly. The drywall, the OSB, and the bricks all have their associated R-Values and could add another R-Value of 2 or 3 (check with your distributor for associated R-Values).