New Roof for Old House
I am renovating a 100 year old house with original pine board roof decking, no insulation and a shingled roof that is way past its useful life. The roof has multiple dormers with the associated valleys.
I have been struggling with getting a solution for weeks now, speaking to roofers and insulation installer and reading everything I can online.
I have a very good spray foam installer that I’ve worked with before and have been happy with the outcome. But that was on new construction.
I am concerned that if we use closed cell spray on the underside of the 100 year old pine board roof decking a couple of things will happen: Foam will seep up through holes and cracks in the board and the roof decking will not be able to breath (and therefor rot).
I’ve gone through various ideas on what to put on top of the pine boards: vapor permeable or vapor impermeable membrane and then shingles; rigid insulation then osb decking then felt or other membrane then shingles; furring out decking to create a soffit to ridge vent then decking etc.
I am looking for the simplest and least expensive solution that will create a heatlhy, long lasting roof.
I am trying to get the roof done before the weather gets too cold. Spraying will have to happen at a later time.
Thank you for the help!
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