Would redoing the roof earlier than planned change insulation advice and be cost effective overall?
Zone 5/6 line in small NH town with no code officials. Retrofit for 1820 two-story Cape 1-story kitchen/dining sandwiched between main house and two-story attached barn that is ¾ converted to living space, ¼ garage (garage poorly insulated with sliding barn door that leaks to air and critters). Granite/rubble foundation, poured concrete floor with good drains but bulk water ingress in the springtime, so planning gutters and likely interior drain on uphill side and sump also to mitigate radon.
Converted space has cathedral ceiling (no purlins, 5″ rafters which all butt together with no ridge beam), board sheathing with gaps to felt paper, dormers, soffit vents, no gable or ridge vent, batting and T&G. T&G and FG batts will come out, although one vendor said to rake out FG and dense pack and air seal over the T&G despite leaving unvented: “we do this a lot; they’ve done this in NE forever.” Other vendor advised to spray foam this roofline and dormers and fireproof them. This is the worst section for ice dams.
Wish we could dense pack the roofline with smart membrane, as we’d love to not do something as permanent as spray foam to an antique cape. SF seems the only way to code R value without 475’s method of extending rafters to 10″. We love that rock wool can be used to dense pack.
Middle attic has 4″ purlins between 6″ king rafter beams, board sheathing, no dormers, roof vents as only way to ventilate (between two two-story house sections). 8″ FG under floorboards that is only storage in house. Advised to SF roofline by one vender, vac out and SF joists by other. Concern is future wiring/perforation of SF seal, so leaning toward the roofline.
Main house attic has 6″ king rafters and purlins, small gable vents, dormers with the tiny gable vents,no soffit vents, loose rock wool between joists. Second story slopes are blown with rock wool.
Main house stays almost 20 degrees cooler than the 80-90s outdoor summer temp. now, for most of day, being kept shut with insulated window shades. (All opened all night for cooling like my mother and grandmother did.) These hot days, basement is wet on the floor from in spots not from rain.We run fans down there to keep air moving and have a heat pump water heater.
Advised to SF the slopes and dormers, and blow in to code on attic flat. One vender said enlarge gable vents due to no soffit vents.
We have paused to consider that when we bought our forever home in 2014, it was projected to need new roofs in 5-10 years. Shingle over felt may be replaced by metal, possibly removing barn dormers for future solar.
We are somewhat paralyzed with the fear of permanent (not green/unhealthy) SF but mostly because of this beautiful antique cape. We even wonder if moving up the redoing of the roofs along with the insulation project could change the insulation advice to allow funds to shift from expensive SF to dense pack rock wool and cover more of the combined roofing/insulation job, albeit sooner than originally planned (just to avoid SF – are we crazy)?
I’ve subscribed and read numerous Q&A threads and have read several of the basic intro articles (such as insulating cathedral ceilings). Very much appreciate any ‘if it were mine to do’ advice, in light of the “permanence” of the project. Thank you, Terry
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