Attic Knee Wall Insulation R Value

Insulating this space inside the knee wall improves the energy efficiency of the home and prevents heat transfer from the attic.

Attic knee wall insulation r value.

Don t forget to verify that the r value of the roof insulation meets minimum code. Cavity insulation as indicated in approved construction documents completely fills the knee wall cavity with no compression or gaps the manufacturer s r value mark is readily available and meets the approved r value per construction documents. This knee wall has been encapsulated with 2 part closed cell spray foam. Most computer programs allow the user to calculate gross wall areas and subtract window and door areas.

According to a report by the washing state university extension energy program blown in fiberglass insulation provides an r value of between 2 2 and 2 7 per inch. One downs side to spray foam down side is cost. The attic tent is the ultimate attic access insulation cover ever invented attic stairs scuttle holes knee wall doors and full size doors its primary design is to stop air infiltration between the home and attic the most common medium for wasting costly residential energy during both hot and cold seasons. At an r6 per inch it provides an air barrier and outstanding thermal break.

By adding an r19 to the existing r13 cavity insulation the knee wall assembly total r value is near r30 and is air tight. This gives a total r value of r 17 r 13 fiberglass plus r 4 for the solar guard sometimes we will change the solar guard out for r 30 fiberglass rolls which gives a total r value of r 43. Walls are entered by the type of assembly and the r value of insulation. Georgia recognized this problem about a decade ago and started requiring all attic kneewalls to have sheathing on the attic side and to be insulated to at least r 18.

Bring the attic inside insulating between the rafters simplifies the air sealing details. The best way to provide that sheathing is to use a rigid material. 1 use an r value map to determine the amount of insulation you need. A 2 x 4 wall cavity with blown in fiberglass insulation will provide on average an r 13 to r 15 insulation value.