ICF home - insulating roof and radiant floor heating
My wife and I are about half way completed with our ICF home in Southwestern PA. Here is a link so you can get an idea of what we are building.
Now for the questions.
ROOF INSULATION. Since the home is made using ICF, there is no issue in insulating the walls, only the roof. The home has some 9 foot ceilings and some vaulted ceilings. The builder is recommending cellulose insulation. I am leaning toward spray foam insulation. The builder states that the attic area must "breathe". Everything I read about spray foam says that it will create an air-tight space. Is it important for an attic to breate? I want to have the spray foam insulation blown in just under the roof throughout the entire home and the builder wants to use cellulose just above the ceiling and leave the attic area to breathe.
HEATING - The entire home is being heated by radiant floor heat. The HVA contractor is installing the radiant floor heat as the only source for providing heat to the home. I do not doubt that it will be enough to heat the home in the coldest of weather. My concern is that I may need heat in the fall or spring just in the evening or mornings. Will the radiant floor heating be good for the days when you just need heat for a part of the day?
Thanks for helping out.