How To Install Insulation Against Roof To Make Attic Conditioned

The first layer will sit between the joists and the second layer will run perpendicular over the joists.

How to install insulation against roof to make attic conditioned.

Unless you re using mineral wool insulation or your fixtures are rated safe for contact with any type of insulation don t allow the material to touch or cover recessed cans or. The quest for greater energy efficiency in buildings has led to increasing interest and need for insulation improvements in hvac equipment more airtight construction new materials and assemblies. Insulation is then installed up to the bottom of the roof deck. 2d extend insulation into joist space to reduce air flows.

You should install two layers of insulation in your attic. Install the ridge vent. When securing the batts to the roof deck it is critical that the batts be held firmly up against the roof with minimal compression of each batt and minimal gaps between batts. Remove the existing ridge cap shingles.

If there is a desire to make that space conditioned to protect stored belongings if moving everything out to air seal and insulate at the attic floor would be a hassle and or if insulating at the attic floor would remove storage space then insulating at the roof line is a better option. Foam insulation above the roof deck to keep its temperature above 45 f throughout the year or spray foam insulation under the roof deck to keep interior moist air from contacting it. Wood joists must be covered to allow the air to move. Experts usually advise builders that you can t install fiberglass insulation directly against the underside of roof sheathing.

An alternate to spray foam insulation in an unvented attic is plenum trusses which allow you create a reverse bulkhead above the ceiling plane that is insulated. Box out light fixtures. Either include a ventilation channel between the top of the fiberglass insulation and the underside of the roof sheathing or install enough rigid foam above the roof sheathing to keep the roof sheathing above the dew point during the winter. It has the highest r value of any insulation material is a vapor retarder and provides a tight air seal.

Closed cell spray foam can be used in any climate. Look for water stains on the roof sheathing or damp or moldy spots on attic joists and existing insulation as a clue to where leaks might be. In finished attic rooms with or without dormer insulate 2a between the studs of knee walls 2b between the studs and rafters of exterior walls and roof 2c and ceilings with cold spaces above. If you want to install fiberglass between your rafters you have two basic choices.

The first layer should have the facing against the drywall to act as a vapor barrier. If you don t already have a ridge vent you ll have to do a bit of work to install one. Now that you have proper ventilation it s time to think about keeping the conditioned air in the conditioned space. For this application the roof framing is typically truss construction with 2x4 or 2x6 truss top chords.