Insulating and air sealing knee-wall attic spaces

One of the most common style of home that Racine Home Insulators, LLC retrofits with insulation is the 1-1/2 story home with a finished attic.  This is a very common style in Racine and Kenosha.

The finished attic consists of separate sections that may require different sealing and insulating methods:

  • The peak attic, located above the finished attic.
  • The sloped roof or slanted ceiling wall
  • Knee walls, between the finished attic and unconditioned attic space.
  • Outer ceiling joists (floor), between the heated room below and the floor of the knee-wall

Expansion Attics in Story-and-a-Half Homes Diagram
Racine Home Insulators, LLC follows these specifications when insulating finished attics:

  • Seal attic bypasses before insulating.
  • Create an airtight and structurally sound seal in the joist space under the knee wall.
  • When possible, insulate the slant wall with dense pack cellulose
  • Insulate knee walls with dense pack cellulose or fiberglass batts covered with house wrap.
  • When the knee wall area is used for storage, create a dam to hold back insulation and/or construct a cold storage platform to maximize R-value.
  • Weatherstrip and insulate knee wall access hatch/panel to R19.

Once this work is done to the attic and knee-wall homeowners will notice a definite moderation of temperature of their upper level. This method of insulating also helps eliminate ice dams in this style of home.

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