sub-floor replacement issues

bubbler · 01-03-2011, 07:23 PM

The previous owners of my house let a shower and toilet leak persist that ruined the sub-floor in the bathroom, and a few joists (which are going to be sistered).

I've gutted the room down to studs/joists, but what I've found is that the bottom plates for the walls that make up the bathroom are sitting on sub-floor planks, and those planks are rotting out.

I had expected to be able to just cut to the perimeter of the room and lay new T&G sub-flooring and add some 2x10 blocking to the joists below as needed. But I don't know how to address the fact that a couple of the walls are sitting on rotten wood, I'm not sure how to address this.

So my questions are--

1) What is the appropriate way handle the rotting sub-floor under the bottom plates? Should I support the walls, then try to pry out the old flooring and wedge in new stuff?

2) Around the tub I've got more issues--not only the sub-floor is rotted, but we've also got rotted bottom plates, and also the edges of some of the vertical framing members. I pried out one of the bottom plates because it was complete rotted, and I cut the vertical members, my intention is to replace them, however since the sub-floor is rotted underneath and that's what the bottom plate was on, there isn't anything to put the new stuff on

This particular bottom plate runs parallel to the joists, so it relies on the sub-floor to support it.

We have a family friend who is a professional carpenter, he's going to be coming to by this weekend to give us advice and hopefully to work (I asked to hire him), but in the meantime I'd like to better understand what I'm in for.

I didn't take any shots of the affected areas, so I'll just put in a general shot--I know I always like to click on the topics with a picture

samps70 · 01-03-2011, 09:36 PM

sorry but you & me are in the boat a sinking one!

bubbler · 01-03-2011, 10:18 PM

Quote:

Originally Posted by samps70

sorry but you & me are in the boat a sinking one!

At least if it was a boat I'd have an excuse for all this water damage!

Ron6519 · 01-04-2011, 08:28 AM

Posting photos of the effected area would be to the point. Seeing the structure that needs to be dealt with would bring specific procedures to remedy the situation as opposed to a series of woulda couldas.
Ron

bubbler · 01-04-2011, 08:53 PM

Pic #1 above... The above pic is looking up from my basement, from left-right are the two joists. The the sub-floor plank has rotted and split in half... it's supporting the bottom plate of that wall (bottom plate seems OK)... So how do I get sub-floor out, and new sub-floor under it? The wall may or may not be somewhat load bearing.

Pic #2 above ... this is a different area... looking "up" from the basement again, I've already pulled the bottom plate, so you can see a stud or two hanging down... this wall divides the shower area and from a neighboring closet... so on the left is "shower" and on the right is "closet"... My thought is that I need to cut back the existing planks to the joist (on the right) ... insert new sub-floor and then add another 2x10 as "blocking" to hold up the edge of that new sub-floor... then I can add in new a bottom plate.

Pic #3, same as Pic #2, just a slightly different angle

Pic #4, I'm not sure if this is valuable, but it's a shot of the closet... so on the other side of the wall to the left is the shower valve etc, you see a hole through to the basement... so that wall is currently totally unsupported from below (and has been since the wood was just rotted away)

Ron6519 · 01-04-2011, 08:58 PM

If the 2x 10 hasn't been effected, all you need is a 2x4 nailed to the 2x10 as a base for the repair section of subfloor.
Ron

bubbler · 01-04-2011, 09:16 PM

Quote:

Originally Posted by Ron6519

If the 2x 10 hasn't been effected, all you need is a 2x4 nailed to the 2x10 as a base for the repair section of subfloor.
Ron

Ok, good to know... though I have plenty of 2x10 which I can use, so either way...

One of the joists is quite bad (see pic below)... the view is in basement looking up again...

I'd like to sandwich it between two 2x10s, but on the other side of the joist is the toilet drain, so there isn't enough room... a sister on this side will have to be sufficient.

Ron6519 · 01-04-2011, 09:34 PM

The strength of the damaged 2x10 is one thing. The other is that it supports the subfloor. You need to make sure the subfloor has a stable base to be secured to. If you need a nailer on the otherside, a 2x4 will do the trick. It doesn't have to be continuous, just so it supports the subfloor. Using exterior grade ply will help as it can bridge some minor gaps.
Ron

bubbler · 01-04-2011, 10:07 PM

Quote:

Originally Posted by Ron6519

The strength of the damaged 2x10 is one thing. The other is that it supports the subfloor. You need to make sure the subfloor has a stable base to be secured to. If you need a nailer on the otherside, a 2x4 will do the trick. It doesn't have to be continuous, just so it supports the subfloor. Using exterior grade ply will help as it can bridge some minor gaps.
Ron

I'm planning to use GP "DryPly", I've seen mixed (mostly bad actually) reviews online... but it seemed like the best choice out of what was available at Home Depot... I knew I wanted T&G if possible, and I knew I did not want OSB due to the potential for swelling should another leak occur... so I settled on the DryPly which is T&G and has a coating to protect against water... I'll have a hardiboard or durarock base for the tile over that.

I plan to sister the bad joist with another 2x10--the end that is near the main beam is "bad" as it has the water damage, on that end the new joist will be put onto the main beam. On the other side the existing joist is OK, so I may just end the new joist before hitting foundation and will put bolts/washers/nuts through them The sub-floor that goes over that part should be continuous, so having it supported should not be a big issue.

It's the side walls that scare me because I need to get new sub-floor under the existing bottom plates... another shot of what I mean--the sub-floor plank is split down the middle (half is already broken off and removed), you can see the bottom plate on top of it... so I need to get that broken plank out, and about 3" or so of the new sub-floor in under the existing bottom plate...

Ron6519 · 01-05-2011, 08:41 AM

It looks like the wall is an interior wall. If you bolt a horizontal 2x6 on that wall up 7 feet or so and secure 2x4's in under it at an angle and screw it to the floor, you can sawzall the fasteners above and under the subfloor and remove the piece. Slide the new subfloor in and secure it to the joists.
One layer of 3/4" ply will not stiffen the floor enough for tile.
Ron

bubbler · 01-05-2011, 01:23 PM

Quote:

Originally Posted by Ron6519

It looks like the wall is an interior wall. If you bolt a horizontal 2x6 on that wall up 7 feet or so and secure 2x4's in under it at an angle and screw it to the floor, you can sawzall the fasteners above and under the subfloor and remove the piece. Slide the new subfloor in and secure it to the joists.
One layer of 3/4" ply will not stiffen the floor enough for tile.
Ron

Hi Ron,

The trouble w/ that is that it will mean I'll have a seam in the sub-flooring, as I'll have to work around the 2x4's... but it may be necessary as I would rather do that on this side vs. the finished other side.

Regarding the tile--3/4" ply followed by a cement board is not sufficient for a tile floor?

Joists are 2x10 @ 16" OC

A professional contractor is replacing the floor in my kitchen (10'x13'), he said he intends to strip back what is there to just the 1x6 planks, add screws between plans/joists, add a cement board layer, then tile over that. Frankly I'm more concerned about that area because it's a larger space, I assumed 3/4" ply + cement board was sufficient for a tile floor.

Ron6519 · 01-05-2011, 03:52 PM

"A professional contractor is replacing the floor in my kitchen (10'x13'), he said he intends to strip back what is there to just the 1x6 planks, add screws between plans/joists, add a cement board layer, then tile over that. Frankly I'm more concerned about that area because it's a larger space, I assumed 3/4" ply + cement board was sufficient for a tile floor."
The man is a complete idiot. The floor will start popping in less then a year.
Check out the John Bridges tile forum for subfloor guidance.
Ron

01-04-2011, 08:53 PM	#5
bubbler Member Join Date: Oct 2010 Location: North Shore MA Posts: 478	sub-floor replacement issues Pic #1 above... The above pic is looking up from my basement, from left-right are the two joists. The the sub-floor plank has rotted and split in half... it's supporting the bottom plate of that wall (bottom plate seems OK)... So how do I get sub-floor out, and new sub-floor under it? The wall may or may not be somewhat load bearing. Pic #2 above ... this is a different area... looking "up" from the basement again, I've already pulled the bottom plate, so you can see a stud or two hanging down... this wall divides the shower area and from a neighboring closet... so on the left is "shower" and on the right is "closet"... My thought is that I need to cut back the existing planks to the joist (on the right) ... insert new sub-floor and then add another 2x10 as "blocking" to hold up the edge of that new sub-floor... then I can add in new a bottom plate. Pic #3, same as Pic #2, just a slightly different angle Pic #4, I'm not sure if this is valuable, but it's a shot of the closet... so on the other side of the wall to the left is the shower valve etc, you see a hole through to the basement... so that wall is currently totally unsupported from below (and has been since the wood was just rotted away) Last edited by bubbler; 01-04-2011 at 08:58 PM.

01-04-2011, 08:58 PM	#6
Ron6519 Member Join Date: Mar 2007 Location: Long Island, NY Posts: 9,519	sub-floor replacement issues If the 2x 10 hasn't been effected, all you need is a 2x4 nailed to the 2x10 as a base for the repair section of subfloor. Ron

01-04-2011, 09:34 PM	#8
Ron6519 Member Join Date: Mar 2007 Location: Long Island, NY Posts: 9,519	sub-floor replacement issues The strength of the damaged 2x10 is one thing. The other is that it supports the subfloor. You need to make sure the subfloor has a stable base to be secured to. If you need a nailer on the otherside, a 2x4 will do the trick. It doesn't have to be continuous, just so it supports the subfloor. Using exterior grade ply will help as it can bridge some minor gaps. Ron

01-05-2011, 08:41 AM	#10
Ron6519 Member Join Date: Mar 2007 Location: Long Island, NY Posts: 9,519	sub-floor replacement issues It looks like the wall is an interior wall. If you bolt a horizontal 2x6 on that wall up 7 feet or so and secure 2x4's in under it at an angle and screw it to the floor, you can sawzall the fasteners above and under the subfloor and remove the piece. Slide the new subfloor in and secure it to the joists. One layer of 3/4" ply will not stiffen the floor enough for tile. Ron

01-05-2011, 03:52 PM	#12
Ron6519 Member Join Date: Mar 2007 Location: Long Island, NY Posts: 9,519	sub-floor replacement issues "A professional contractor is replacing the floor in my kitchen (10'x13'), he said he intends to strip back what is there to just the 1x6 planks, add screws between plans/joists, add a cement board layer, then tile over that. Frankly I'm more concerned about that area because it's a larger space, I assumed 3/4" ply + cement board was sufficient for a tile floor." The man is a complete idiot. The floor will start popping in less then a year. Check out the John Bridges tile forum for subfloor guidance. Ron

sub-floor replacement issues