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ksanders22
Insulating a lean to porch

My house was built in 1982 with a lean to porch. I enclosed the porch and now need to insulate the roof on the porch. The ceiling consists of 2 x 6 rafters with open perlin and a metal roof on top. I need to insulate between the rafters but the ceiling is already low and I can't drop it down enough to provide a proper vent space above the insulation.

My thought was to remove the metal roof, add decking and tar paper then 2 x 4 perlins on top of tar paper and then a metal roof. I would then add 6" of insulation between the rafters. Would this give me enough air gap between the roof and insulation? Since this is a lean to porch, there is no way to let air out at the peak of the roof. I live in central Texas and the temp. gets over 100 degrees in the summer. Any advice would be greatly appreciated.

Thanks

Timothy Miller
Re: Insulating a lean to porch

Howdy, how about installing fiber glass insullation in the joist cavity then 4 by8' by 1" insullation foam panels as the ceiling or then drywall over the foam. Your perlins above the joistsallows air flow as long as you do not insulate above the joists.

ksanders22
Re: Insulating a lean to porch

Thanks for the info. I was just worried about enough air space above the insulation.

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