Building Homes or Extensions/Insulation
I am remodeling a 1925 western bungalow in Cleveland, Ohio similar to the picture I have attached. I have an unconditioned central attic space that I use for storage with 2x4 roof rafters and soffits and ridge vent for ventilation. I will be gutting my dormer space and bedrooms of the plaster and lath and intend to insulate the sloped ceilings as there is not any currently. I would like to do spray foam insulation to maximize my r-value with the limited space I have to insulate. What is the depth of the air flow channel I need to consider for proper airflow for the roof. Would I use Closed or open cell insulation? Would I stop insulating the rafter space where the bedroom/dormer ceilings end or carry all the way to the peak? Do I need to add a vapor barrier between the insulation and drywall? Thank you for the reply.
Hi Anthony, nice older bungalow. These question would best be discussed with your building department and insulation company. I build in Canada where the building code may be different. Vapour barrier is not required if the insulation company's specs say it isn't, although some building departments want it anyway.
Unfortunately these questions fall into a grey area where it is just better to ask what they want - yes that's what we do to make life easier.