stick framing a shop sagging troubles on the main beam please help!!!

weekendwork

i stick framed my shop roof and its 20 by 20.it is sagging in the middle.i used a 2by8 for the main beam with 2by6 rafters. i think what happened is i bought 2 10 feet 2by8s and spliced them. any help on getting the sag out of the center??? any help will be GREAT!!!!!!!

jproffer

...**long whistleeeeeeeeeeeeeeeeeeeeeeeeeee**...um...ok **rolls up sleeves**

A secondary beam half way up (down) each rafter, and a post on each end and one in the center holding it up (however I assume you would have issues with this method...since there would be a post in the middle of the floor).

A Glu-Lam or LVL engineered to span 20 unsupported feet in the same location described above with a post only on the ends.

Sister a 2 x 6 on each side for at least 4 or 5 feet above and below the original splice. (To do this, the original rafter would have to be jacked up in such a way to allow attaching these 2 x 6's on each side while it's supported in the correct position)

Similar to above: Sister a full 20 foot 2 x 6 onto each existing rafter (basically a new rafter without removing the old...these would obviously have to be cut properly on the ends to work correctly)

Order 16 (for 16" centers) or 11 (for 24" centers) trusses and replace the entire roof system. (I know, I know. I'm just throwing out ALL the options I can think of)

Live with it. (but keep a CLOSE God....blessed eye on it if you're going that route)

I'll keep thinking...and I'm sure someone else has ideas different from (and probably superior to) mine.

K2eoj

[[/QUOTE]

I'm seeing a different picture tha jp. Sounds like your ridge is sagging because it is spliced. Your rafters are one piece and are probably about 12 ft. from the wall to the ridge. If that picture is correct than you could probably get a designed beam, (micro-lam, lvl, gluelam), under your existing spliced 2x8 beam, (ridge), jack everything up, and post down to the foundation. if you post down to a header, (opening), make sure your header is sized. If my picture is right then your walls are pushed out and if you jack everything into place be sure your walls come too. > You could probably do a fix with collar ties or ceiling joists and I think there are some threads around here on that subject. I guess it held you and a bunch of bundles of shingles slaming around so it can't be too bad but i think I would get a temporary brace on it if you were expecting snow. HS

AaronB

:confused: :

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jproffer

OHHHHHHHHHHHHHHHHHHHHHHHHHH....yep...re-read....the RIDGE is sagging...sorry...be back later to think some more about the REAL problem

Teetorbilt

Run a stringline along the top plate, on the inside and paralell to the ridge beam. This will tell you if the walls are bowed out and by how much, I'm pretty certain that they will be.

To straighten everything out; put a couple of eyebolts (not screweyes) through the top plate with a big washer on the outside. These will be central and opposite to each other. Connect a come-along between the two eyes and slowly pull the two walls back together, your roof will be going up at the same time. This may also take a day or two, don't force it too much at a time. Once the walls are back to being flat, pull them in about another 1/2-3/4" to account for future settling. Now install at least one crosstie. If it were me, I would put one on each side of a central rafter and fasten with epoxy and throughbolts, wait 48 hrs. for the epoxy to cure and then release the come-along.

You will probably need to splice a few 2X8 min. to make the span. Use another 2X8X10' to make the splice.

jproffer

It's better to keep all posts in the public eye. Never know, someone else may have the same problem. :D

Anyway, if the roof isn't covered yet (bare studs and rafters) I would truss it. You will lose a little "attic" space so to speak, but maybe not as bad as you think. You can get trusses that look like this with a minimal loss of "headroom"

DISCLAIMER: DO NOT attempt to build trusses using that drawing, the engineering isn't correct and the bracing shown is just an example of what a scissor truss MAY look SIMILAR to.

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weekendwork

I tried using those metal deck braces. first I jack up the center about 3\4 inch with my tire jack and a board. next I placed the deck braces in and doubled up my rafters in the center. I removed the jack and happy to say the main beam is dead on level with my string line I ran across the main beam. also my walls stayed level. problem solved. THANKS TO EVERYONE THAT HELP!!!!!! :D

Bonus

What are "Deck Braces"? Unless they're something that ties the walls together, your ridge is GOING to sag again, and your walls spread. You need either ceiling joists, collar ties (in the lower third of the rafters) or a sized beam under the ridge spanning the length of the building with appropriate support to the ground, or a post in the middle of your building, again with support to the ground.
Your 'problem' is not that you used two short members for your ridge, that is commonly done in stick framing roofs, it is that you have missed half of the structure story of the roof, the rafters transfer the roof loads to the walls and change a component of them to horizontal, you need something to counteract this outwards force on the walls.