Subfloor repair

[Barry]

I posted this pic quite some time ago showing rot around my toilet from below.

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I have now removed the toilet, a layer of tile, a layer of vinyl flooring and the two layers of underlayment that were accociated with the flooring.

I cut the rot out and now have one problem and that is supporting the new subfloor I must install.

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On the west side the tounge is available so that will not be a problem. For the north, I plan to cut back to the floor joist or alternatively cut even with the joist and add a sister to the floor joist to make things easy for myself. On the east, I will add a 2x4 to connect the floor joists and use that for support.

That leaves the south... it is an outer wall and the floor joist is 6 inches in (beyond the floor I have cut out. I can only think of two options (since there is plumbing in the way to make things worse.... (1) Add a hanger 6 inches in between the two joists, then put in a crosser of some kind... or (2) screw some thick plywood to the bottom of the existing subfloor and use that for support.

Any advice or other options?

[marson]

your idea of screwing some plywood is a good way to go. you could also use a chunk of 2x material. if you use 3" drywall screws, you can screw from the top and draw the backing tight to the bottom the existing plywood. better check the insulation in the rim joist area and make sure everything is dry and in good shape.

[Colbyt]

NSWE without references confused me. I am assuming that your problem is with the area where the toilet supply line is. Other than the wall sitting on it, I can not see that area getting a lot of traffic. If you can figure out a way to properly support a 2x4 under the cut edge of the osb it will support the minimal load you need supported. Use a joist hanger at 1 PM position and the 8 PM position and run the 2x along that axis.

My answer is as confusing as your question.

Here 2000 words. Add 2x4 or better where the red lines are.

I would add the extra cross bracing under the toilet flange also.

[Barry]

Getting good acess at the 1 pm and 8 pm positions may prove to be a problem as the joist is in about 6 inches under the concrete block with a gap of about 6 inches for access. What do you suggest a hanger?

As for the insulation, it is all in perfect condition. The water never touched the outerwalls of the bathroom or otherwise.

[Colbyt]

A single or double joist hanger depending on how straight you cut is.

There are a couple of ways to do it. All of which would work. But you have to think about the deal killers, home inspectors when you sell. With that in mind my preferred approach would be to use joist hangers and to attach them to the rim joists and to the added headers. I would use 1.5" #8 hex head screws in lieu of nails. Installed using a cordless drill and a 1/4" hex head bit with a 6" shaft this lessens the misery a little. Isn't going to be fun. This type of repair never is. For the angled nail into the hanger I would use a 2" or longer #8 hex head. There will be a couple you just can't get to and I would not worry about them. You won't find a one piece 1/4" x 6" hex driver at the BORG. Look for a local screw supply company. Should cost about $5 unless they see you coming.

It looks like your joist are 2x8. If you can get a 2x6 over the water pipe, I would use that instead of 2x4. It really isn't needed IMO in this case but remember the deal killers.

Second best option would be cut blocks on 2x material and wedge under them using shims to secure a tight fit.

Colbyt

[Barry]

Thanks... I will get the hanger in there...somehow.... The exhaust pipe you can see in the insulation will requite use of 2x4 .... by looking at it.... butI will measure and try for a 2x6 if I can..

How do I get the new sub under the flange.. work around it with 2 pieces making up the new sub floor ....or cut the flange out and redo the PVC?

[Colbyt]

I have done it both ways more than once. One each in the same bathroom. :). I think in the future working with ABS or PVC I will always cut the pipe and add a coupling somewhere. It just makes life simpler that way. If it is in an exposed location (crawlspaces are exposed) you can use a Fernco rubber coupling to reconnect the pipe. They cost 5-6 bucks but they sure are easy to work with.

I hang around here a lot but make note of my email address, remove the obvious, and contact me direct if I miss one of your posts. Mention alt.home.repair in the subject because I delete a lot of crap without ever looking at it.

Colbyt

[Barry]

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Done