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.

How to extend roof rafters for insulation.

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. The baffles will allow circulation to continue even though insulation has been installed directly in the path of the rafter air movement. They are directly below the roof sheathing and are were insulated with fiberglass batts stapled between the 2x4 rafters. I have a 1925 bungalow in michigan climate zone 5.

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. Ceiling joists are the horizontal boards that span the width of the house resting on the outer wall plates and possibly on. 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. How to extend rafters.

2d extend insulation into joist space to reduce air flows. The first issue is with regard to how to insulate the sloped portion of the roof. Under a slate roof. How to increase the interior ceiling joist for r38 insulation.

So we need to do two things. 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. Modern u value targets mean installing insulation between rafters only is rarely a viable option. How to insulate 2x4 rafters.

Air circulates from the lower part of the roof overhang through the rafters and out the ridge vent of your roof.