Reinsulate attic?

Bought a small brick Colonial last June.

Attic has blown-in fiberglass between the joists on the floor. The joists are covered with plywood.

I want to keep using the attic for storage, but I also want to insulate it better. Also, the fiberglass fill seems to generate lots of unpleasant dust.

My questions:

(1) Would fiberglass batts generate less of that dust? Right now when I go up there, I feel like I have to wear a cheap respirator, and over time the dust gets on the stuff we put up there, which is annoying. (If it were just general dust, I wouldn't care, but I get worried that it's fiberglass dust.)

(2) Insulation-wise, the space under the "floor" (height of joists) is a little less than 6". Reading about insulation on-line, seems like that's not a lot of insulation---so it might not even be worth insulating better. (Apart from the dust issue.) If we add more, though, we'd either have to get rid of the floor boards and have no storage space, or, as a friend suggested, increase the height by nailing some wood on top of the joists, then putting the floor boards on top of that. Is that a good idea?

Temperature-wise, it's not that cold here---I live in the greater DC area.

TIA,

S
Reply to
stephen.fromm
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Bought a small brick Colonial last June.

Attic has blown-in fiberglass between the joists on the floor. The joists are covered with plywood.

I want to keep using the attic for storage, but I also want to insulate it better. Also, the fiberglass fill seems to generate lots of unpleasant dust.

My questions:

(1) Would fiberglass batts generate less of that dust? Right now when I go up there, I feel like I have to wear a cheap respirator, and over time the dust gets on the stuff we put up there, which is annoying. (If it were just general dust, I wouldn't care, but I get worried that it's fiberglass dust.)

(2) Insulation-wise, the space under the "floor" (height of joists) is a little less than 6". Reading about insulation on-line, seems like that's not a lot of insulation---so it might not even be worth insulating better. (Apart from the dust issue.) If we add more, though, we'd either have to get rid of the floor boards and have no storage space, or, as a friend suggested, increase the height by nailing some wood on top of the joists, then putting the floor boards on top of that. Is that a good idea?

TIA,

S
Reply to
woger151

If it's covered with a plywood floor, where is the dust coming from? Are you sure it's from the fiberglass?

I'd say it's because you only have 5 1/2 inches that it's probably worth it to insulate more. But you are right, that also limits your options. You could remove the fiberglass and go with sprayed in foam, which can have a value as high as R7 per inch.

How much more insulation will benefit you depends a lot on where you live. MN and SC are too very different places.

I'd say the problem is if you do that, to get any significant increase in R value using fiberglass or similar, you're going to have to raise it up so much, it's use as a convenient storage space will be gone. If you;re willing to give that up, then remove the plywood and install batts on top. Otherwise, consider removing what's there and going with the sprayed in.

Reply to
trader4

Ususaly old rock wool or cellulose is dusty. You have about R 20 now, where I live Zone 5, R 35 is minimum and R 60 optimal.

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might help you. Unfaced batts under a raised area should work.

Reply to
ransley

wrote

Are you sure it is fiberglass? If the house is older, it may be other. The seller may have *told* you it was fiberglass but it's not.

It shouldnt which is why I question it being fiberglass.

There is none to speak of from the batts.

Grin, you wont get full value is you crush it down a bit but you can put the rolled batting down there betwen them then the plywood back on.

How high is the space? Is it almost room sized or is it a crawspace? If almost room sized, this will work.

Still worth it there.

Reply to
cshenk

Wouldn't you think the blown-in insulation would settle down? Maybe in a few hours after the install? I have both in my attic. There will always be some dust up there so I use plastic totes for storage.

The wooden floor has insulation properties as well, plus boxes stored on the floor will have some insulating properties. You might want to get an infrared thermomter to test the attic for areas needing caulking.

Reply to
Phisherman

Gee if the attic is floored with plywood it's hard to see how the "fiberglass" dust is escaping. It could be plain old ordinary dust, such as accumulates on everything everywhere over time. The attic has vents to the outside, right? Dust happens.

Also, the blown-in stuff may be rock wool, which looks and feels somewhat similar to fiberglass but for some reason does not have the same health concerns.

I had a similar situation, floored attic used for storage, with, in my case, even less insulation under there, just a couple inches in most places. I sure as heck did not want to rip up all that flooring. First, I got rid of as much stuff as I could. Then, I built some low platforms to put stuff on - each one a 4X8 sheet on a frame of 2X4s, with little 2X4 legs to raise it up about a foot. All cheap materials. Then I insulated the attic with rolls of fiberglass laid on top of the flooring, leaving a corridor down the middle for a walkway. The insulation runs under the platforms. The platforms run along the walkway. Now I have insulation (on 90% of the area) and storage too. Incidentally, I used Mansville Comfort-Therm insulation, it is wrapped in a thin plastic sheet to contain the fibers. The plastic is thin and gets ripped easily, etc. but I figure it's better than nothing. -- H

P.S. you could also use old card tables, etc. to get stuff up off the floor.

Reply to
Heathcliff

No, I guess not. I just didn't see any other source of dust, and maybe I'm paranoid about breathing in fiberglass.

Yeah, that's what I'm thinking.

Thanks for the suggestion about the foam; I'll look into that.

Reply to
woger151

Yes, you're right, I can't know it's fiberglass. Just paranoid. Not that I'm sure a teeny bit of fg dust is all _that_ harmful.

OK.

Yeah, that's a really good idea. I'll look into that. Thanks!

Reply to
woger151

(sigh) Seller didn't tell us jack. I don't know much about this stuff, but I figure it's fiberglass. (Had to reassure SWMBO that it's almost certainly not asbestos.)

OK, thanks for the point.

OK.

It's definitely bigger than a crawl space, but not really room sized either.

I think I might adopt the other poster's idea about having a central ally with elevated stuff on the sides to put storage items.

Thanks for the useful tips and for replying. Cheers.

Reply to
woger151

There's dust everywhere. Especially in properly vented attics. What makes you think the fiberglass has anything to do with it?

Reply to
Bob F

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