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Discussion Starter · #1 ·
First off this is for my own house. I have read numerous posts on spray foam, cellulose and fiberglass blow in insulation, and to be honest I only have hands on with cellulose. I know that I need more insulation in my attic, currently there is only R-15 batt insulation installed on 24" o.c. We have a whole house fan that we use early in the mornings and late evening to pull cool air in with, vented soffit, I would replace the soffit baffles with better ones but the originals are still there currently, and box vents near the ridge so I think I have adequate ventilation. There is one house near by that had spray foam installed on the underside of the roof sheeting when it was built new and the owner is just crowing about the low utility bills. I talked with the installer and he said it was very do able to install spray foam an existing house. He also talked about making it a "closed" attic, to me it sounded as if he would take all the ventilation sources out and spraying the foam on the underside of the sheeting. Is this correct? I also asked about spraying the foam on the joist cavities and he said that was an option also if we took the batt insulation out and then we could lay it back in afterwards. I am thinking that I would like to get to an R-60 factor. Lets hear the pros/cons and do's and don'ts.
 

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The guy you're looking for on here is probably SLSTECH. Also, details vary by location in the country, so you probably should post that in this thread, or add to your profile:thumbsup:
 

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Discussion Starter · #3 · (Edited)
I am in NW KS and is a climate zone 5, and says the ceiling R value should be 38, but if I go to OC they recommend the R60. Of course they are selling insulation to. I might be wanting to over insulating. I did do some reading on slstech blog I believe.
 

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Sean
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First let me say, I believe there is a gentleman in your area named John Nicholson aka Energy Guy Kansas, it would be worth paying him to do a full energy audit.

In answer to your questions, I can only add about a hundred more without seeing it but in general;
  • Both a hot roof & regular approach will save you money & make you more comfortable if done right
  • If you go with a hot roof - it should be closed cell foam & you will need 6" or 3 lifts (depending on manufacturer) to eliminate almost all chances of dew point concerns - that will get you to an R36 to 42
  • If you go traditional - review the entire attic air sealing series I did
  • Yes you can spray the ceiling with foam which does a good job of air sealing & then top off with a blown in product (no batts)
  • As for the whole house fan - if you are going to keep it, then that rules out a hot roof unless you want to develop a chase with an exterior exhaust. For a regular attic, make sure it is insulated & I would run foam boards up the side past the top of the insulation unless you get a unit that takes care of that
  • If you have any atmospheric vented equipment inside the building envelope - change it out to direct vent
  • You also need to control indoor moisture - use bathroom & kitchen exhausts
 
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