Renovating attic to living space in 1850 Northern Vermont Home- venting and spray foam Qs
I’m renovating my 1850 attic with a 12/12 pitch roof in Zone 6 to make livable space (master bed/bath)
Asbestos containing insulation was professionally removed from attic floor joists and new insulation is to be installed against roof.
I am planning a 1-1.5″ vent baffle against sheathing. Rafters are 6″ deep, with rafter bays 20″ wide. Planning to add furring strips perpendicular across rafters to allow spraying full 7″+ depth over baffles and cover rafters with at least 2-3″ of spray foam (avoiding heat loss strips at rafters). Goal is to get R49 roof or better.
Roof is in process of being replaced; standing seam with ridge vent (dormers have ridge vent too) I know it would have made long term sense to add two layers of foam on top of sheathing. Cost was an issue. Also, with roofers so backed up in this area I had to make commitments last spring to ensure I would be able to close up before winter.
Unico HVAC heating/cooling system to be installed so ERV should ensure no interior humidity issues.
Will replace the existing 2″ softet holes spaced ~24″ OC with a continuous softet vent strip.
Any feedback or tips for this plan are hugely appreciated.
What is minimum depth recommended for baffles? Could 1″ work?
Rafters are structurally sound but somewhat uneven in spacing because of house movement over the years (19-21″ in spots). Is there a baffle that is easier to work with with such inconsistency? Should I just onsite build with cardboard or filter fabric?
Attached is a picture from inside the attic of the two Velux windows that we’re really excited about for this space, as well as new metal roof in process.
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