Energy Audit - I need to insulate the attic


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Old 03-04-14, 02:47 PM
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Energy Audit - I need to insulate the attic

Hi Guys,

I had an energy audit and it was suggested that I increase the insulation in the attic as my 1976 original fiberglass is in pretty bad shape.

The attic is a walk up with decking over the center third of the space for storage/walking. The areas under the eves are clear of decking and just have the old batting. I do have my 2nd floor central ac air handler in the attic.

What is the best bang for the buck here in terms of tightening things up. I was told I could remove the current insulation and spray-foam the foor decking underside.

Another option was to raise the floor and add blown-in insulation, though raising the entire floor may be difficult.

I have several pot lights, some under the existing decking and some exposed where there are clear gaps evidenced by discoloration of the insulation. In addition, I have a lot of wires coming up from interior walls.

The floor of the attic is about 1500 sq ft. I'm willing to put in the labor if the rewards are worth while. I am hesitant to throw thousands at a spray foam contractor for marginal return.

Where should I go, what should I read, and what do you suggest?

Thanks,
Bryan
 
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Old 03-04-14, 05:05 PM
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What R-value are you shooting for? How deep are your joists?

What is the best bang for the buck here in terms of tightening things up...

I have several pot lights, some under the existing decking and some exposed where there are clear gaps evidenced by discoloration of the insulation.
Unless those recessed fixtures are both IC (insulation compatible) and AT (air tight) they should be replaced with ones that are. You'll probably get as much energy savings out of doing that and air sealing your ceiling as you will out of adding insulation. More, if you just add insulation without doing the sealing.

The better solution would be to remove the recessed fixtures and close the ceiling.

I have a lot of wires coming up from interior walls.
If there is any space around those cables where they penetrate the top plate, it should be filled with fire-stop caulk.

The areas under the eves are clear of decking and just have the old batting.
Any insulation outside the exterior walls, lying on the soffit, needs to be removed so that intake ventilation can be restored or added there.
 
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Old 03-05-14, 07:57 AM
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Where should I go, what should I read, and what do you suggest?
The ZIP Insulation Calculator.
 
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Old 03-11-14, 09:40 AM
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Learning as I go...

I've had 2 estimates thus far.

1st was to spray the underside of the roof decking with 6" of closed cell foam, to bring me to R39. $7800.

The 2nd quote was to use spray 6" of open cell to give me a R19. $5200.

Both suggest sealing the attic and making it conditioned space. I have 2 more estimates coming in today and tomorrow. I'm curious to see what method they suggest...

The rafters are 2x8, I believe but will check on that today.

I am entitled to $1/sqft in state rebates for the job.

I would ultimately like to finish the attic down the road.

Thoughts?
 
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Old 03-11-14, 10:21 AM
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If you plan to finish the attic, I would spray the rafters. My attic will never be living space so I insulated the floor and left the rafters open for ventilation.
 
 

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