need to cut truss - Scared


Old 08-09-05, 06:58 AM
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need to cut truss - Scared

I need to install an air handler in an attic. it is 3"wider than the truss spacing (24"). The entire ceiling under ther trusses has been covered with 1/2" OSB nailed at 6" intervals. I am planning to cut one truss and frame out an opening and use 2x12 's laying flat on top of the trusses as beams to 'take" any tensile load that may occur (these would be connected with lag bolts). Is this adviseable? will the OSB take the lionshare of the load? Will the 2x12s take the rest? or .... is this a very bad idea?
Old 08-09-05, 04:42 PM
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Without seeing it myself, and not being a framing carpenter, I'd for sure say *do not* trust OSB, it's cornflakes and glue. Decent for it's purpose, but not known for handling extreme stresses.
Old 08-09-05, 04:42 PM
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I would never ever ever cut a truss, Ever!
Old 08-09-05, 07:54 PM
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You have good reason to be scared. As stated before, cutting a truss is not a good idea. That truss is engineered to withstand load because of it's design, and altering it's design will compromise is load handling capability.

Bad idea.

Is there another size air handler that you can get, or some sort of reducer for it to fit between the trusses?
Old 08-09-05, 08:20 PM
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hmmm, you guys are scaring me even more than i was before. tomorrow im going to call the truss manufacturer and see if they have records showing the tensile load in the bottom member. depending on that, i will decide how to proceed. maybe its only a few hundred pounds.

maybe i could remove some osb panels and stretch two trusses apart temporarily to hoist up the air handler. im hesitant about that because i would be possibly affecting two trusses instead of one.

another idea is to cut a section out of one truss, lift the unit in place, then bolt the piece back using steel support plates. i guess thats the safest route.
Old 08-10-05, 05:58 AM
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Take a drawing of what you plan to do to the truss mfg. If there's a way to engineer it safely, they'll know how.

The company I work for makes roof and floor trusses and this is the only reasonable way to go.

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