Bathroom Floor Repair

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Old 12-16-07, 09:00 AM
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Bathroom Floor Repair

I am trying to rebuild part of a bathroom floor to install a new shower and tile, but am concerned about the structural integrity due to some rotted floor joists. The more I demo, the more problems appear. Here's a synopsis of what I discovered:

I am remodeling what I think is the original bathroom in a 1920s home. The tile floor of the bathroom is built on a concrete slab that appears to be about 8 inches thick. I can stand under the slab in the basement, it looks like it was poured between the floor joists. At some point, a main support beam of the house was cut (for plumbing) under the bathroom, causing the concrete slab to crack and the bathroom floor dropped up to an inch in some parts. When I bought the house the home inspector didnít seem concerned and said it looks like itís been re-enforced enough to arrest future movement. However, any water spilled on the floor would run downhill and fall into the basement through a large crack in the tile and concrete.

I demoíed a cast iron tub which gave me access to the edge of the tile on the concrete. I should note beneath the tub I found very rotten supports on the plumbing end of the tub. I canít tell how badly these affect structural integrity but it ainít pretty. Anyway, at this point I was able to easily stick a pry bar under a top layer of concrete and remove large square foot sections of concrete with its mosaic tile still attached. These square foot pieces are about 1.5 inches thick and upon removing them I can now see the tops of the joists (which are rotten in places). The concrete between the joists is crumbly and has a variety of cracks. I stopped after removing about 1/6 of the tile in this fashion and realized I was getting in over my head. Now what?

Should I continue? Should I build a wood subfloor over the concrete? Should I attempt to replace the rotted joists or use an epoxy filler to strengthen? Should I attempt to seal the cracks in the concrete and pour self leveling compound? Should I hire a contractor?

Thanks...I know that's a lot of information and questions, but any advice will be helpful.
 
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Old 12-16-07, 11:11 AM
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There may be quite a lot of information coming your way on this post, so I will get started. Shower technology has come a long way since the 1920's. Pouring concrete adjacent to wood is inviting a disaster. Would it be possible to demo the concrete completely? If so, you could start back by sistering your joists, thereby giving additional strength, then starting your vertical build, whether it be with a built up berm and 40 mil shower pan, or if you want to go with a manufactured pan either in fiberglas or marble. Let's start by the feasibility of the concrete demo. You may want to post a couple of pictures on a site such as photobucket.com and give us the urls. It always helps to see what you see.
 
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Old 12-16-07, 11:22 AM
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It all depends on your skill level AND if you have an "if someone else can build this, so can I", attitude.

I have been fortunate to learn an AWFUL lot from working on houses built from the 1860's to the present and have encountered about everything there is to encounter, and thankfully I get to do more easy stuff now (like work on mechanicals where my feet are on the ground and I stay dry and don't breathe asbestos, lead, fiberglas, mildew and mold, and plaster/sheetrock dust the way I used to.) I have done many bathroom demo redos and have seen such concrete pours like you describe.

From what you say, it sounds like something bad structurally happened/is going on, and it sounds like a complete gut and redo is the way to go.

Naturally you will be creating a lot of debris and getting rid of it will cost you more time and money. But the floor load will be lightened and you will be down to where nothing is hidden anymore. Then either sister on new joists where needed or put in new ones.

You must consider finished floor height for at the bathroom door and also the toilet flange height, and other things like where the existing baseboard trim was, the height of tub, etc. To avoid any more problems you will want to have the finish height of the floor to wind up where it is now, most likely.

It sounds from the description of the substrate that tile was the plan from day one. But I just want to bring up that in cases where tile is added say over original 8 inch square asphalt floor tiles, let's say, then often you can relower the floor height back down to that level because what they often did in these types of ceramic tile redos was to butt the new tile up to the tub and use a toilet extension flange.
 
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Old 12-16-07, 06:19 PM
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Here's a link to a gallery of images that might help explain my situation. Thanks for all your info so far!

http://picasaweb.google.com/EricChri...oom_renovation
 
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Old 12-17-07, 06:45 AM
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You should send the pics to This Old House and say. "What should I do?".

2 x's turned flat ways for support and braced. Sheesh. Quite unorthodox.

I'd just tear out the whole works and start completely over to the point that it is completely open to the basement, and rejoist it. If any plumbing drain runs are in your way (looks like that is why they put in 2 x's the flat way and then supported with cross beam and post), either turn joists the other direction or redo/reroute the drain in pvc.

It looks like quite the disaster, but to me, this brings back fond memories from the not too distant past with old houses and water damage to bathrooms in trailers. "Gutting", is gutting - and for anyone with demolition-remodel/building experience, it can be kind of fun actually, because there is great satisfaction when you consider the 'before' to the 'after'. You are already on your way with some good 'before' pictures.
 
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Old 12-17-07, 10:11 AM
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ecman51,

You're scaring me. Let's make sure you are interpretting the pictures correctly, though. To be sure, the joists under the bathroom are 2x7's oriented vertically (the standard way). There are what look like 1x8's turned horizontally between the joists. These appear to be resting on 1X1 strips that are nailed to the joists. The 1x1 strips are nailed 2 inches from the bottom of the joists. My assumption is that this was done so concrete could be poured between the joists and rest on said 1X8 planks. So if I were to remove the concrete and the 1x8 planks, I should be left with standard 2X7 joists, right?

You may be right that they were smoking crack when they built this (or whatever they smoked back then). But the rest of the house appears to be built very well, with solid construction and very beefy heart of pine wood. It would surprise me if the bathroom was done poorly. Not that it matters but the tile on the concrete in the bathroom was a hand-layed mosaic so someone spent some cash originally. I would have left it alone if I hadn't lost the remodelling battle with my wife.

Anyway, after reading this post do you still believe I should gut it?

BTW - I posted to This Old House per your suggestion.
 
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Old 12-17-07, 12:10 PM
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Originally Posted by ecjacobson View Post
BTW - I posted to This Old House per your suggestion.
. Good for you. I wonder if they will comment?

I will go and take another look at the photos based now on what you are saying.

I just did and it still looks to me like sizeable area with 2 x's used as joists, laying flat. ??? And I don't see rows of 2 x 8 joists every 16 inches on center. That 4 x 4 cros-support up at the ceiling: What size wood do YOU say that is holding up?

Wish there was photo more vertical, looking straight up. (Bottom-left photo)
 
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Old 12-17-07, 04:59 PM
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ecman51,

Per your request, I took a picture looking straight up from the basement floor at the underside of the bathroom. I added arrows and text in yellow to be more clear. Try this.

http://picasaweb.google.com/EricChri...09399416810242

Hopefully this picture will show that there are 2x7 joists at 16" centers. You can certainly see old water damage too.
 
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Old 12-17-07, 06:29 PM
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Thank you.

Did they put in all those 1 x 12's lower than the tops of the joists? (is that what they did?) so that they could pour concrete on top without having the height of the bathroom floor get too high?

So why not just gut it all out back down to the joists? Get rid of that now-needless weight.
 
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Old 12-18-07, 04:38 AM
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I will reiterate my original post and further Ecman's posts....gut it. You will be alot happier with the results, and will have fun in the meantime. The laterally lain 1x12's were there just to hold the concrete pour. Since concrete is watery, what happened to the water before curing??? It soaked into your wood, so that can't be good. Removing all that will give you the latitude of making the floor the height you want to coincide with adjacent flooring.
 
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Old 12-18-07, 09:30 AM
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Thanks guys. Your advice to remove the concrete seems logical to me. I don't plan to "gut" the joists but I think sistering them seems like a good idea. Give me a few weeks and I'll post back on the results.

BTW - ecman51, I believe your assessment about the 1 x 12's was correct
 
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Old 12-18-07, 10:21 AM
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That new photo really helped.

Good luck on your project. Make sure nobody is down under there when you start busting stuff up.

Looking forward to reading your progress report. (You can PM to remind me, also, in case I don't see the post.) And if you have any other snafus along the way, let us know.
 
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