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Blown in attic insulation blown away...

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  • Dec 21st, 2009 2:44 pm
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[OP]
Newbie
Jul 20, 2006
40 posts
2 upvotes
Scarborough, ON

Blown in attic insulation blown away...

Hello fox,

I need your help on this one please:

This morning I noticed a water spot on the ceiling of my master bedroom. There was no rain in the last few days here in Scarborough. I went up in the attic and sure enough I found some spots that were bare; I could look right at the drywall of the ceiling below. There was condense under the plastic barrier which led to that water infiltrating down.

http://img709.imageshack.us/img709/5671/p1130163.jpg
http://img706.imageshack.us/img706/9481/p1130164.jpg
http://img709.imageshack.us/img709/9678/p1130165.jpg

This is a new house and I'll contact the builder tomorrow morning. I assume (hope) they will come and fix it. What I'd like to know is why this happened in the first place and how to avoid it in the future?

I also took several measurements of the thickness of the insulation in unaffected spots: it read 10". Is this according to the Building Code?

Thank you!
10 replies
Deal Fanatic
User avatar
Oct 22, 2007
6026 posts
968 upvotes
Mississauga
When I added blown in insulation to my attic I installed soffit vents to allow cirulation to travel throught the attic. This is important for several reasons which we won't discuss at this point but it allow directs air flow upward and not across which may be the situation in your case, which allowed air flow to slightly blow the blown in insulation to uncover the ceiling area. Google soffit or ridge vents and you'll see a picture of what I'm referring to, then cross reference to see if you home has it in the area that is causing your issues.
Deal Guru
Aug 2, 2001
13009 posts
3789 upvotes
Blown in insulation will typically shift over time - I had a 2 foot "hill" of it in my attic when I went to top mine up.

It could mean that the insulation was improperly installed in the first place, however you will never know. The best thing to do is fix the issue and inspect the rest of the insulation.
Deal Fanatic
Jan 16, 2003
6224 posts
84 upvotes
Yeah you definitely need baffles. I'm surprised that they weren't installed.. I though that it was minimum code.
Deal Fanatic
User avatar
Jul 4, 2004
6937 posts
343 upvotes
Think Pink!

What we did was put bales of fiberglass pink over the blown insulation and find that it not only keeps the blown stuff down but it also keeps everything nice and level.
[OP]
Newbie
Jul 20, 2006
40 posts
2 upvotes
Scarborough, ON
Thank you very much to all of you!

I've contacted the builder and I'll see how the issue is going to be fixed. (Pink insulation on top of the blown in one along the soffits or baffles or something else...).
Meanwhile I'll try to find out what the minimum is required by the Ontario Building Code with regards to this matter. Any link to an official site?
Member
Dec 2, 2003
412 posts
11 upvotes
Ottawa
How deep/thick is your blown in insulation? Hard to tell in the pics, but it doesn't look like a thick cover. From what I can find, cellulose is R3.6-3.8 per inch and your 2x6's (I hope they are 2x6's) are just covered? Might be worthwhile adding some more insulation while you are fixing any venting issues (if there are issues).
[OP]
Newbie
Jul 20, 2006
40 posts
2 upvotes
Scarborough, ON
Ride-On wrote:
Dec 21st, 2009 1:24 pm
How deep/thick is your blown in insulation? Hard to tell in the pics, but it doesn't look like a thick cover. From what I can find, cellulose is R3.6-3.8 per inch and your 2x6's (I hope they are 2x6's) are just covered? Might be worthwhile adding some more insulation while you are fixing any venting issues (if there are issues).
The yellowish piece of lumber is indeed a 2x6. I measured the thickness on several spots and I got 10". Is that OK?
Sr. Member
Oct 28, 2007
633 posts
10 upvotes
Ottawa
viking wrote:
Dec 21st, 2009 2:06 pm
The yellowish piece of lumber is indeed a 2x6. I measured the thickness on several spots and I got 10". Is that OK?
Taken from the BuildingHomes forums:

There are 2 values given by the manufacturers: the depth when installed [blown thickness], and a depth after settling. I find that it takes not less than a year to reach the settled thickness. The manufacturer's instructions provide the specific instructions, but the most commonly accepted values for cellulose insulation in an attic are:

* 12" blown thickness for R40 (actually works out to R45.6)
* Settles to 10.5"= R40.

* 14.7" blown thickness for R50 (actually R55.1)
* Settles to 13.15" (R50)

The settled R Value for cellulose can be calculated as 3.8 per inch
[OP]
Newbie
Jul 20, 2006
40 posts
2 upvotes
Scarborough, ON
Zedix wrote:
Dec 21st, 2009 2:25 pm
Taken from the BuildingHomes forums:


* 12" blown thickness for R40 (actually works out to R45.6)
* Settles to 10.5"= R40.
I think this is what I have. It must be the minimum required per the Building Code as I don't think my builder would have exceeded it especially in such an unnoticeable place.

The house was finished in October 2008 and stayed unoccupied until July 2009 when we bought it. It is probably settled down now after one year and a half. This explains my measurements of 10" (given or take).

Edit: I forgot to thank you, Zedix!
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