My Attic Insulation Experience (in process)

If the old insulation isn't fouled re-use it. I have about an R-30 in my attic which was all acquired from demolitions and left-overs from job sites. Since I don't store anything up there it works for me.

vinny11950 said:

put in some Roxul R23 insulation

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What did you pay for that, per square foot, if you don't mind me asking?

Nice job.....

Have you looked into the cost of having it spray foamed ? Or are you just wanting to do it DIY.

vinny11950 said:

Thanks, still a lot to go.

Funny things is, I have spent about 25 hours up there so far spread across 4 Saturdays, and every time I come down, visually it looks like I have done nothing to the house.

But I did manage to get those joists bays filled right before the cold snap 3 weeks ago and it has made a big difference.

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Yea it will make a big difference, I'm on LI also, I think next week will be the turning point for us....you will be all setup for next winter....

Your attic looks similar to mine. A few years ago I had bad ice dams. After doing some reading I did the following:
Added soffit vents (there was a ridge vent but no soffit vents)
Added insulation baffles at the eaves to keep insulation clear of the vents.
Air sealed.
Added an additional R30 FG to the R16 that was there.
House stays much warmer now, and my house is one of the few houses in the naborhood that don't have ice dams.

When I was working in the attic, this is what I used for PPE.
Hard hat with led flashlights zip tyed to the side.
goggles
Respirator
Tyvek suit
knee pads
gloves with old socks to cover forearm.

Good luck with your project.

I've been putting off an attic insulation upgrade for some time, likely for the same reasons you put off yours - it's just such a nasty job and not a nice place to spend a lot of time.

When I bought the house, it had maybe R-19 (6" fiberglass) in the attic in the ceiling joists underneath some floor decking. About 10 years ago, I put another 8" of fiberglass on top of that. There are two problems with this - 1) I have read that fiberglass loses a lot of insulative value in very cold temperatures and 2) I go into the attic 2x a year to close or open the gable vents, and I have compacted the fiberglass in places, reducing the insulative value.

I like the idea of the Roxul batts since they are springy and won't compact, and won't lose insulative value in colder weather. I saw them on the HD and Lowes sites, and I think I'll put some 24" wide R-30 batts up there on top of the areas that have wood decking (I was going to build a higher decking surface, but I think I'll just skip that as I don't store anything up there) and move the existing fiberglass to add depth to areas that don't have decking.

Thanks for prompting me to go forward with this.

DBoon said:

I have read that fiberglass loses a lot of insulative value in very cold temperatures and 2) I go into the attic 2x a year to close or open the gable vents, and I have compacted the fiberglass in places, reducing the insulative value.

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When I looked into this a few years ago, the studies showed the effect most strongly in loose fill 'chopped' fiberglass, that was popular as a blow/rake in product for attics in the 50/60s (?). I had that stuff, compacted down to maybe 2-3" deep. Looks like irregular small cotton balls with **big holes** in between. It makes sense that with the coarse texture of the stuff, convection can set up in the big holes.

The numbers for R-value loss in modern FG batts are much more modest, i.e. hard to measure, and in my opinion not worth replacing FG over, unless (maybe) you lived in Yellowknife.

I think this rather limited laboratory result many years ago, that one kind of (obsolete) FG loses significant R-value in very cold weather has been repeated by competing insulation makers to the point of convincing us that FG is almost useless.

DBoon said:

I like the idea of the Roxul batts since they are springy and won't compact, and won't lose insulative value in colder weather. I saw them on the HD and Lowes sites, and I think I'll put some 24" wide R-30 batts up there on top of the areas that have wood decking

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Working with Roxul is actually kind of fun when compared to fiberglass. I absolutely hate working with fiberglass. I used Roxul in my basement. The only personal protective equipment I found really necessary was a good respirator. I wore light gloves also but found myself working in short sleeves -- inconceivable to me with FG.
I used a serrated bread knife and tape measure for making cuts. The texture reminds me of a loaf of bread.

woodgeek said:

not worth replacing FG over

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Well, I'm not going to throw it out, just move it from one place to some other place...