Air Vapor Barrier R Value

Vapor barrier 0 0 common rules of thumb type of building section r value wood frame walls 3 plus r value of the insulation used floors above unheated spaces 2 plus r value of the insulation used ceilings 1 1 2 plus r value of the insulation single glazed windows 0 88 double glazed windows 1 67.

Air vapor barrier r value.

Do tyvek weather barriers have an r value. This is an important part of keeping heat in and or out of a space in walls attics crawl spaces etc but isn t a replacement for thinking about air and vapor barriers. An example of this are self adhered modified bituminous membranes and sheet polyethylene which can be used as both an air barrier and a vapor barrier. Ccw 705 air vapor barrier strips datasheet sds detail self adhering flashing for detailing ccw 705 and barriseal systems.

The products work equally well as air or vapor barrier on precast concrete cast in place concrete masonry concrete block interior and exterior gypsum board styrofoam primed steel aluminum mill finish anodized aluminum primed galvanized metal drywall and plywood. It s a house wrap engineered to keep homes cool in the summer warm in the winter and dry all year round. Does not consider internal convection effects does not consider presence absence of reflective barriers does not consider directions of heat flow up or down nor winter summer conditions. When used with one side exposed to an attic skyflex adds an additional 1 7 r value to the system.

Even at wind speeds of 5 mph a wall without an air barrier retains less than 40 of its original installed r. When one or both sides of skyflex air barrier is exposed thermal resistance of the wall increases. In hot humid climates vapor barriers should not be used. How it adds r value.

A few more factors. Insulation is rated in r value with the higher the r value the greater the resistance to the movement of heat. Call us at 800 342 5976. However properly installed tyvek weather barriers help protect against loss of r value in insulation due to wind washing.

Ccw 705 xlt strips datasheet ccw 705 xlt is a low temp version of 705 strips. Ccw 705 twf xlt datasheet a 40 mil thick self adhering. Also note that there are differences for inside vs outside air films. The r 0 87 value for the first value in this air r value table subsection.

Ccw 705 twf datasheet sds spec detail certs self adhering thru wall flashing.