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-   -   so, i used 2x6's .... (http://www.diychatroom.com/f19/so-i-used-2x6s-158678/)

Fix'n it 10-02-2012 08:56 AM

so, i used 2x6's ....
 
... for my ceiling joists. 14' spans 16"oc. sistered to the existing 2x4's. notched out 1 1/2" to lower them to cover the sag in the original 2x4's.

no, this seems plenty strong enough. but guys on another forum (non DIY) are saying they are going to sag down soon and i will have to replace them.
what do you think ?

Pittsville 10-02-2012 10:10 AM

It depends on a number of factors. What's going on above the ceiling joists? Are you storing anything up there?

GBrackins 10-02-2012 01:21 PM

if it is attic space, do you have stairs (fixed not pull down) that access the attic?

tony.g 10-02-2012 04:36 PM

If it is just a ceiling, and you are not storing anything up there, and assuming a dead load of approx 8psf, the deflection of your 2x6s alone (ie without the existing 2x4s) would be about 5mm, assuming a cheap-grade timber.
Codes normally specify a limit to deflection as a fraction of the span, and for ceilings it will be around span/200 (though this varies) meaning an allowable deflection could be up to 20mm on that span.
However, some codes require a small amount of live load to be added to allow for use as storage, which will increase the deflection, but probably not that much.
This doesn't take into account the existing 2x4s, which willl help a bit, so personally I wouldnt worry about it.
(sorry my figures are in metric; unfortunately we have to use this rather than Imperial and I had to convert and re-convert!)

GBrackins 10-02-2012 04:53 PM

tony,

2009 International Residential Code requires 20 psf for limited storage attics, if accessed by fixed stairs 30 psf

Fix'n it 10-03-2012 08:20 AM

the only thing that is going to be stored up there, is a bunch of cellulose . yes, there is a pull down stair, i so i can get up there easily to do the work needed. and i will be building a catwalk over the center wall (so no load on the joists) so i can get access to the back of the attic. so when i work on the back of the attic, i do not disturb the insulation.

i walked on the old setup, it blowed some, but it held me. now, with the P&L down (this stuff weighs a lot) and the 2x6's and lightweight drywall up. the ceiling is MUCH more solid.

Fix'n it 10-03-2012 08:21 AM

oh. idk what grade of lumber is it. i got it from HD and it was $10 each.

Fix'n it 10-03-2012 08:37 AM

1 Attachment(s)
pics ..........

hmmm, seems i can only load 1 pic at a time :huh:

Fix'n it 10-03-2012 08:39 AM

1 Attachment(s)
#2 ....

Fix'n it 10-03-2012 10:06 AM

wow, no comments ...

anyway. i was told to do it that way, by you guys, a while back. but i cannot find that thread now.

NetTractorTalk 10-03-2012 10:27 AM

Give the pros a little time. I figure they are out earning a few dollars. They'll comment later. Looks good to me, but sure not my area of expertise.

mae-ling 10-03-2012 11:04 AM

vague memory here,a #2 or better spf 2x6 can span about 12' as a ceiling joist at 16" centers, with insulation and drywall on it. No storage.

So your 14' span is over that but you also have a 2x4 beside it, So my guess is you will be Ok.

Fix'n it 10-03-2012 07:40 PM

ok. so, how do i find out the quality of my lumber ? there are markings on it, but idk what they mean.

Pittsville 10-03-2012 09:29 PM

Quote:

Originally Posted by Fix'n it
ok. so, how do i find out the quality of my lumber ? there are markings on it, but idk what they mean.

What are the markings? Take a photo if you can.

Gary in WA 10-03-2012 09:58 PM

Chart: http://publicecodes.cyberregs.com/ic...?bu2=undefined

What R-value on the cellulose?

Gary


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