Attic insulation - foam?

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Old 05-03-19, 12:35 PM
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Attic insulation - foam?

I have a mess of insulation in my attic. Some are batts (most aren't snug rafter-to-rafter either) and old loose fill. There is a lot of roof trash up there, and a lot of the insulation has been disturbed over the years.

I'm wondering:

1) What would foam cost for a 1,600 sq. ft. one-story home?

2) Do the foam companies typically vacuum (or otherwise remove) all the old insulation, etc. as part of the job?

3) Would I be better to clean up some of the bigger pieces of trash (roofing materials), and just blow-in several more inches of loose fill over the top of what is already there?

Many thanks for good advice. I put up a picture so you can get a partial idea of what it looks like.
 
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Old 05-03-19, 04:17 PM
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In an attic you would use batts, or I would highly suggest blown in cellulose!

Foam is mostly used in walls!
 
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Old 05-03-19, 05:52 PM
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Yuck !!! when it looks that bad on top who knows what rodent deposits are underneath. I would advise removing it all and installing new and I like blown cellulose.

There are two issues besides the final r-value.
One; with insulation neatness counts. Any voids limit the potential final insulation value.
Two; with everything removed you will have much easier access to do a god job of air sealing. Air sealing is considered a top priority and yields the biggest bang for the effort.

Spray foam would make any future work up there almost impossible.

If you want to consider batts, some of the mineral wool products are high in r-value and fit tight together. I like Roxul.

Bud
 
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Old 05-04-19, 12:29 PM
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How would air sealing work? I've already foamed most of the wire holes and I am putting boxes over two canned lights. To my knowledge that is the worst of the direct openings.
 
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Old 05-04-19, 01:36 PM
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Of course every home is different and i can't see yours so some of my comments will not apply.

If you have a basement and the ceiling area is exposed check around all plumbing penetrations. The main sewer vent will also pass through the attic along with other vents that join it.

Showers and tubs often have large areas of the floor removed for pipes and those areas give air a path into the walls and into the attic.

If your heating system has a chimney there may be a path around it.

Drop ceilings above kitchen cabinets, bath vanities, showers, or or stairway walls can be sealed on one side only.

A porch overhang may have been attached before the sheathing was installed providing a bypass.

There are more possibilities listed here.

Bud
 
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