Insulating an existing roof
I have a home built in 1910 in Minnesota and I am replacing the roof shingles due to storm damage. When the roofing contractor came out to investigate, he noticed below the shingles were the original 2x boards used as sheathing (as oppose to sheets of sheathing) and they were spaced too far apart to meet current code. There also isn’t any insulation between the 2×8 rafters (attic space was finished to be an occupied room). There are a few existing roof vents sprinkled thru-out the top-half of each roof face, but we don’t have soffits (the rafters continue to the overhang) or air vents at the bottom of the roof.
The roofer wants to replace all of the boards and lay down new sheathing boards, add new roof vents (either the box kind or ridge vent) and add insulation (type not know yet). This leads me to many questions:
1) If there are no soffit vents, is the ridge vent doing anything for us?
2) If we add insulation between the rafters and replace the board sheathing with continuous sheet sheathing and add a new ridge vent, how will air circulate to the ridge vent?
3) Was the space between the existing 2x “sheathing” acting as vents for air to travel to the existing roof vents?
4) Should we just not add insulation and replace the sheathing and roof vents and call it a day?
Thank you very much for your assistance and guidance.
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