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ruined floor joists


rebeljeep's Avatar
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01-15-08, 08:44 PM   #1  
ruined floor joists

I am remodeling a room. I discoverd some floor joists that someone cut holes into for some plumbing. The hole are really big and on the end of the joist. I'm told that there should be at least 2" of wood left at the top and bottom of holes in joists. Some of these joist only have 1". How can I beef these joists up and make them strong again.

 
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thezster's Avatar
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01-16-08, 05:49 AM   #2  
Assuming those holes don't currently have pipes running through them - You can "sister" a matching 2 X to the existing joists - using a layer of 1/2inch plywood between the lumber - coating with glue - and screwing it all together.

 
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01-16-08, 10:15 AM   #3  
Posted By: thezster Assuming those holes don't currently have pipes running through them - You can "sister" a matching 2 X to the existing joists - using a layer of 1/2inch plywood between the lumber - coating with glue - and screwing it all together.

I actually have several floor joists that have been notched (or worse) for plumbing, ect. I was going to do this same thing, but never thought to glue them as well as screw together... and why put plywood in between?
Just curious so I get it done right. Should the existing joice be jacked up (like 1/16 or 1/8") in order to "preload" the new joice? Thats just a thought I came up with, so let me have it!

 
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01-16-08, 10:44 AM   #4  
I like the plywood sandwich to provide for vertical strength between the layers. It's cheap insurance and will help keep the joists from sagging (assuming you use a long splice) in the future.

If you floor shows no sign of sagging currently - and the floor joists appear solid/level - jacking them up a tad probably isn't worth the effort. In the future (when the floor "wants to sag") is when the mated surfaces will come into play - keeping your floor from turning into a topsy turvy funhouse...

 
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