How To Extend Roof Rafters For Insulation

I have a 1925 bungalow in michigan climate zone 5.

How to extend roof rafters for insulation.

By installing high density 8 inch fiberglass batt insulation the rafters will then meet an r 30 roof insulation standard. 1 improve the structure of the roof and 2 allow more space for insulation. For instance if the roof has 2 by 6 rafters and you want r 30 insulation which is standard in many communities you can add a 2 by 4 which will give you an 9 inch rafter space. The baffles will allow circulation to continue even though insulation has been installed directly in the path of the rafter air movement.

The first issue is with regard to how to insulate the sloped portion of the roof. So we need to do two things. The outer ends of a roof s rafters the sloped members that give the roof its pitch provide shade divert rain and create soffit space for attic ventilation. There are some unfinished crawl space areas in the corners on the upper floor.

How to increase the interior ceiling joist for r38 insulation. Air circulates from the lower part of the roof overhang through the rafters and out the ridge vent of your roof. They are directly below the roof sheathing and are were insulated with fiberglass batts stapled between the 2x4 rafters. 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.

How to extend rafters. Under a slate roof. How to insulate 2x4 rafters. Modern u value targets mean installing insulation between rafters only is rarely a viable option.

It allows insulation to be installed in a watertight roof either after the roof covering has been fixed on a new build or without disturbing an otherwise sound existing roof covering as part of a renovation.