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reinforcing floor joists for sewer pipe


scott e.'s Avatar
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Join Date: Jun 2003
Posts: 412

05-12-15, 04:27 PM   #1  
reinforcing floor joists for sewer pipe

I have a 1929 house and I am remodeling the master bath. Long story short this project has really blown up in my face. What started as a simple project, ballooned into a major remodel. When the original house was built, the plumbers hacked the floor joists in my 2nd floor bath to accommodate the cast iron and galvanized drain pipes. Some of the 2x10 floor joists were notched half way through and 8" wide. That, with other reasons, required me to replace those joists. I am preparing for the plumbing again and have gusseted the joists with 3/4" x 9.75" x 8' plywood glued and screwed where I think the new pipes will go through (should be close to a bearing wall, 2' - 3' away, 13-1/2' total joist span). Is that enough reinforcement for the plumber to drill a hole for a 3" PVC toilet drain? Or will I need to do the same reinforcement to the other side? or even more?

 
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joecaption's Avatar
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05-12-15, 04:30 PM   #2  
Not sure how anyone would know without some pictures.
Should be getting rid of all that old steel and cast plumbing, not just working around it.

 
scott e.'s Avatar
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Join Date: Jun 2003
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05-12-15, 04:52 PM   #3  
cast has all been removed. The plumber will be installing new PVC. Gutted entire floor under the bath. Installed new 13-1/2' 2x10 joists across the span. One end of the span, where the toilet will be run, has been reinforced with 3/4" plywood, the width of the joists and 8' long, screwed and glued to the side of the 2 joists (one piece of plywood per joist) the plumber will need to drill through to run the toilet drain. I know that you are not supposed to drill a hole more than 1/3 the width of the joist, and then only in the center, without reinforcement. I just don't know how much reinforcement to add.

 
XSleeper's Avatar
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NE

05-12-15, 05:04 PM   #4  
Large pipes should not need to go through joists. The right thing to do would be to double the joists that will not be notched or drilled, then head off any joist (on each end) that would need to be cut or notched so that there is a clear path for the drains. A picture, drawing or diagram sure would help. We can't see it from here.

 
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