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Insulating the attic - spray foam?

7 years ago
last modified: 7 years ago


We have a 132yr old Victorian (1884) vernacular farmhouse in Nebraska. The attic is large - maybe 800-1000sqt (but not walk-up), with about 9ft at the peaks of the gables and is filled with a hodge podge of blown in (not asbestos, already tested it), fiberglass bats, and pieces of Styrofoam that looks like packaging from old boxes!

Our energy bills are through the roof, still have the massive cast iron 1925 gas fired (originally coal) hot water boiler and big cast iron rads (heats the house great, and comfortable!), plus 5 window air units for summer (hate them with the fire of 10000 suns). Plus there's an original wood burning fireplace on the main floor with a glass door (not a sealed unit).

We have been thinking about our next step - we want to add AC, but think dealing with the massive heat that radiates off the attic might be the best first step.

So we have discussed spray foam. Having the insulation company remove all the current insulations, then spray foam the rafters and bring the whole attic into conditioned space - then it will give us a place to run ducts and an air handler for AC in a cooler environment than the 150+ blast furnace that happens up there each summer.

The roof situation is open planks - with remains of old cedar shakes covered with a couple of layers of asphalt, then topped with Decra metal roofing panels. When we got here there were no roof vents at all. We had six added, but later realized there were no intake vents in the eaves either. Not good. Probably the original cedar roof didn't need them and got enough air between the wooden eaves. But now, the eaves are covered in aluminum, and there's no way to get air into the attic except pulling it from the conditioned space.

So, we're thinking about spray foam, and sealing off the whole attic so it isn't sucking all the heat out of the house in the winter through the whole house fan, and blasting us all summer with radiant heat.

1). Am I on the right track with this idea?

  1. Open vs Closed cell in this situation? Will our roofing materials make a difference in choice?

3) The house is triple brick construction (14inches thick - three layers of brick later covered in 2 inches of stucco, inside the plaster is right on the brick - no wood in the exterior walls) - so the large gable ends in the attic are exposed brick - do we spray them too? (will it damage the brick?) Or just do the roof rafters?

Any thoughts on radiant foil? Before spray foam on the roof rafters? afterwards over the spray foam? only over the bare gable ends? no extra benefit?

One benefit of the 14 in thick masonry walls plus a big wrap around porch - the main floor stays about 10 degrees cooler than outside and the basement stays about 10 degrees cooler than the main floor, but that exposed 2nd floor heats up seriously. Windows are all original (and huge - all 3x7 double hungs), and we have no plans to change them - although I will try to tighten them up as much as possible.

We figured - first fix the attic insulation issues, then get the HVAC guys to install AC, starting with the 2nd floor zone, then see what is needed for the 1st and the basement level.

4) As we baby step our way through this renovation ( we are happy caretakers here at the Shrine to Our Lady of Perpetual Renovation) - we will eventually reach the kitchen and install a Vent-A-Hood so I can actually cook a hamburger without setting off three smoke alarms, but we aren't at that point yet - do I need to worry about makeup air before I get to the kitchen stage? Will sealing off the attic make that much difference?

I know this is a little rambly, but mainly I want to know if spray foam is as good an option as I'm hoping, which type is best, and best application practices for a home like ours.

Thanks for your thoughts!


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