# enginered joists



## evilcyrus (Apr 27, 2009)

hey i was wondering what u can remove on a enginerd joist the ones with plywood bewteen .. i cant rember ..i usally only do commerical work and never deal with this stuff.. do the same rules apply as a reg joist.. please let me know.. Ontario canada.. so ontario building code.

thanks .

Evilcyrus


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## Airgap (Dec 18, 2008)

You can only remove the entire plywood web.. Nothing more nothing less....


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## Bollinger plumber (Apr 3, 2009)

been a while since I have done new construction but when I did it we did it this way as a rule. 1 inch hole 1 ft from bearing wall
2 inch hole 2 ft from bearing wall
3 inch hole 3 ft from brearing wall so on and so forth
as airgap said only in the plywood 
but as I said its been a while it may have changed since then


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## uaplumber (Jun 16, 2008)

Here you can take out all but the top and bottom 3/4" of the plywood.


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## trout lake (May 9, 2009)

What was the question???
What are you asking evilcyrus?
It looks to me the way you wrote it that you want to alter the engineered joist. THe answer to that is "no", thats why they are engineered. If your talking abouit drilling through the gusset, different story. But you didn't ask that


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## Plumber Jim (Jun 19, 2008)

Just look it up on the manufactures website. I used to keep one of the little booklets that had all that in it. If its newly installed it will have one or two booklets taped to a joist here or there. it depends on the TJ you are working with size etc.


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## Optimus Primer (May 20, 2009)

all holes bigger than 1 1/2 have to be like 3 times the hole you drilled away from it. So much a distance from bearing point. Someone posted it already. No square or rectangle holes. and like someone said, you have to leave 3/4" of plywood from the top and from the bottom. The only way you can have closer holes to themselves or bearing point is using the knockouts they give you.


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## uaplumber (Jun 16, 2008)

Whoops, and no hole with 12" of load bearing wall. However, if you make a boo-boo, stiffen both sides with 3/4 plywood, glued and nailed. If the framer has them under your W/C spot, cut the bastard out. They can box it in to repair or run a new joist beside it.


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## PipeDreamer (Mar 26, 2009)

See the manufacturers specs. They have different rules.


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## Protech (Sep 22, 2008)

It's been a while since I took the GC exam but I believe that you aren’t allowed to cut or modify them AT ALL without the direction of an engineer.


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## Bill (Jun 17, 2008)

As a licensed building contractor I can say that the plywood is actually a fire break required at certain intervals according to the width of the building. Any part may be cut out for allowing objects to pass through, but MUST be caulked after with fire rated caulking. Now, the truss itself? Never, and I mean NEVER cut a truss. Period. Technically even when I install roof truss I am not supposed to cut the rafter tails back because it will shorten the truss over all length thus it is not the same as the manufacturers plans.


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## Double-A (Aug 17, 2008)

It varies from manufacturer. Some will not allow any holes in the first 12" of webbing, others will not allow any holes in a 6" lateral by 6" vertical area to either side of a bearing point. 

Some allow only circular holes, others allow square and rectangular holes.

Look at the brand and make of the joist and go to the manufacturers website.


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