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-   -   Replace or sister saging garage joists (http://www.diychatroom.com/f19/replace-sister-saging-garage-joists-69054/)

Billup 04-14-2010 05:45 PM

Replace or sister saging garage joists
 
My garage joists are saging, and have cracks in them that span from 1/2 to 3/4 through the 2 x 6's. The length of the joists is 22ft. The joists run parallel to a vehicle when it is parked inside. The width of the garage is 25ft. Please help me find the best way to fix this problem. Some folks have suggested engineered wood in a I beam configuration but at the end at the base of the roof, I would have to cut the I beam on an angle to follow the roof and that seems like it is defeating the purpose of having the I beam. Some have suggested sistering the whole beam with another 2 x 6 and either screwing or bolting the joists together. Please help.

kwikfishron 04-14-2010 06:16 PM

A picture would be nice.

Gary in WA 04-14-2010 07:13 PM

Install an LVL (laminated veneer lumber) under the existing ceiling joists at the 25' span, with 4-1/2" of bearing at each end. 1-3/4"x 9-1/2" will carry 5900++#'s. You have 22' minus 1/2 = 11' x 25' x 10#live load and 10#dead load = 5500#. (and no center post) http://www.parr.com/PDFs/LP%20LVL%201.9E.pdf Check with your local code enforcement official, they may require stronger than 20# per ft.

Be safe, Gary

jogr 04-15-2010 12:11 PM

GBR's solution is probably the easiest way to go and extremely effective. The only drawback is that possible impact of headroom loss from the beam (for example - possible interference with garage door opener). If the ceiling is high enough then that's not an issue. If it is an issue the beam could be placed within the ceiling with the existing joists cut off at the beam and hung with joist hangers - but that is a lot more difficult. The beam could also be placed above the joists and the joists "hung" from the beam with straps but again a lot more difficult. In most cases the beam below the joists as GBR suggests is your best bet.

Cole 04-15-2010 01:49 PM

22' 2x6's in a garage?????

Yoyizit 04-15-2010 04:34 PM

Quote:

Originally Posted by Billup (Post 428771)
Some have suggested sistering the whole beam with another 2 x 6 and either screwing or bolting the joists together.

Yes. Even low strength 2x6s [E = 800,000 PSI] may solve the problem and you don't need calculations. Try a few first, measure the sag before and after.

Billup 04-15-2010 06:45 PM

I'll get some pics tomorrow.

kwikfishron 04-15-2010 06:52 PM

Quote:

Originally Posted by Cole (Post 429114)
22' 2x6's in a garage?????



My thought exactly, thats part of the reason why Id like to see a pic.

Billup 04-15-2010 07:35 PM

Yes, 2 x 6's over a span of 22ft, I've been told the wood is #3 wood with large knots and that is mostly where they cracked. My first thought was to sister more 2 x 6's of #1 or #2 wood and either bolt or screw them together. Is there any type of 2 x 6" engineered wood that would work better? The large veneer beam mentioned above is probably very heavy and I'm doing this job solo.

meboatermike 04-15-2010 08:51 PM

I believe the beam mentioned above according to the tables attached above weighs 4.8 lbs per foot -- even I, a middle aged weakling :whistling2: would consider this doable.

Yoyizit 04-16-2010 11:16 AM

Quote:

Originally Posted by meboatermike (Post 429252)
I believe the beam mentioned above according to the tables attached above weighs 4.8 lbs per foot -- even I, a middle aged weakling :whistling2: would consider this doable.

I get ~44# for this plank, using 35#/ft for the wood density. The OP may want to use a rope & pulley. ERs are really costly nowadays.

Scuba_Dave 04-16-2010 11:33 AM

Quote:

Originally Posted by Billup (Post 429215)
Yes, 2 x 6's over a span of 22ft, I've been told the wood is #3 wood with large knots and that is mostly where they cracked. My first thought was to sister more 2 x 6's of #1 or #2 wood and either bolt or screw them together. Is there any type of 2 x 6" engineered wood that would work better? The large veneer beam mentioned above is probably very heavy and I'm doing this job solo.

I installed (3) 16" LVL's in my garage for support -great room above & roof.
They weighed under 200 lbs each
The 9" LVL would weigh a lot less - almost 1/2
And is a great solution

Billup 04-16-2010 02:22 PM

Location profile updated. Thanks

Gary in WA 04-16-2010 10:21 PM

With the beam support at 1/2, or 11' - this would clear any opener and back-hang track of a 9' high door. The #3 wood ceiling joists should not have been used there, only very short spans or firewood. The engineered wood is great but you cannot cut the angle past the inside of the wall. (Roof slope). IRC requires 2x6 at 24"o.c. - 10'6" span. 2x8 = 13'3" 2x10 = 16'3" Doubling may work if the local Inspector OK's it for liability, so no one comes to your next house with a lawsuit from your previous work.....

I presume they are 24"o.c.? If drywalling, need 5/8" at 24"o.c. joists.

What is the headroom, under joists to slab?

Be safe, Gary

Billup 04-17-2010 07:42 AM

The joists are 9ft from the slab. I don't know what o.c. stands for since I'm am a true newby in wood construction measurements. So what you're saying is that I can't use lvl since I won't be able to cut it for the roof slope? One friend of mine suggested lowering the wall and putting "I" beam lvls to support it but I'm not keen on that since some folks tell me that to lower the wall I would just be putting 2 x 4's nailed to the wall and resting the "I" beam on them instead of the support wall. So, can I just put #1 wood up against the existing #3 and bolt or screw them together the full length of the joist?


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