Leveling floors, removing old subfloor


Old 05-22-12, 09:41 PM
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Question Leveling floors, removing old subfloor


I need an advice. We just bought 100 yrs old house, everything in the basement seems to be straight, however second and third floors are sagging in the middle (about 2-3 inches), after talking to several engineers/architects nobody seems to be able to pinpoint the problem and all they say that the house is old and it's natural. I still want to level the floor, I removed thin hardwood and it looks like I have 3/4 planks as a sub floor, on the third floor somebody actually laid hardwood right on the joists without a sub floor, and in the bathroom I have about 5 inch of concrete.

So I am planning:

1. install 1/2 inch plywood on top of the sub floor on the 2 nd floor leveling with planks and shingles, does it make sense? would it be better to remove sub floor and replace it with plywood?

2. remove hardwood on 3 rd floor, install plywood sub floor and then put hardwood, does it make sense? would installing sub floor add much weight?

3. remove concrete floor in the bathroom on the 3rd floor and install plywood with cement boards, existing concrete is cracking on joists and I can probably fix it but I think if I remove it I'll reduce the weight it puts on the house.

Any suggestions, opinions welcome.

Thank you.

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Old 05-23-12, 02:46 AM
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Viktor, welcome to the forums! In all you suggest, you haven't solved the problem, only put a Bandaid on it. The floors will still sag. Some older homes were built with balloon framing and clear spans. Nice for the first 50 years, but you see the result. It may be unsightly, but a central post and beam on each floor bearing to a cut and poured footing in the basement may help the sagging. It can be decorated to blend in with the architecture. What is the clear span in both directions on each floor. Is there any support in the basement across the clear span??
Old 05-23-12, 07:45 AM
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I'm with Chandler, you need to support the structure to get the sag removed.

That said, old buildings sometimes object to being moved back, might be good to have someone onsite to look at this project.
Old 05-23-12, 07:19 PM
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Thank you for replying. I am totally with you, I asked few contractors and couple engineers/architects and they all advised against raising floors. In the basement I have main beam which has joists span 16 feet each side and also on both sides I have beams that are in the middle of each span so basically 3 beams and the longest span is about 8 feet, floor on the first floor is absolutely straight. It also looks like the house was renovated 30-40 years ago and they leveled the floor with cement in the second floor bathroom, which I guess means that sagging happened before this renovation and it's been stable since then, I also do not see any signs that sagging continues, do you still think I should try raising sagging part?

Any thoughts about the mud bed on the third floor, any reason I should keep it?

Thank you.

Old 06-21-12, 07:37 AM
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Mud Bed Under Tile

A watchout for you with that bathroom floor. When doing reno on our 1875 home (with ~1910 bath) we had similar issue, with hexagonal tiles over 4-5" mud bed. Most of our old galvanized water lines were actually set in the mud bed. Also, after taking out the concrete what we were left with is floor joists that were "peaked", which is where you see some of the stress cracks forming in the floor. To be able to install a new 3/4" plywood subfloor with Duraboard topper we had to sister new 2x8 joists to all of the existing peaked joists so that there was a flat, level surface for the subfloor to mount to. It's all do-able, but requires a bit more effort than we had planned. Don't miss the opportunity to put in an electric radiant heat floor mat for the bath if you can handle it within your budget. Makes it a lot more pleasant to walk on that new tile floor in the winter time.
Good luck!
Old 06-21-12, 11:44 AM
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Welcome to the challenge, Viktor!

I would not do any adjustment on top of any floor until I had straightened out the framing as much as possible. It isn't about level floors. Floors that are slightly out-of-level can be part of the charm of an older house. It's about structural stability and squaring up door and window openings. And it's about not compounding the problem by adding additional stress to framing that is not in alignment.

I would also avoid installing any new bracing or support where it is visible. I would keep all work inside the existing framing. It's almost impossible to disguise visible changes so that they don't scream "remuddled." What I would do is lift, level and secure the structure.

That said, here are the most important tips I can think of from my experience, both as a contractor and as the former owner of a badly-framed and poorly maintained 1908 home:
  • Remove any wallpaper or other material covering any sloping wall surface. Examine the bare wall to see if there are any places where an opened crack has been filled; remove the filler.
  • Remove anything else that you are thinking of replacing and that might prevent the framing from moving back into alignment. That slab in the 3rd floor bathroom is a prime example. One example: Gutting the 2nd floor bath in our 1908 house, which we did even before moving in, didn't make a lot of difference, since it was just linoleum over flooring to begin with. But you could see, hear and feel the old gal straighten up and stand taller when we tore off the six - yes, I said six - layers of roofing that had been laid on the 2X4 rafters!
  • One that strikes me a particularly pertaining to your situation: It is highly unusual for a lower floor to be structurally level while the floors above it are significantly out-of-level. In addition to closely investigating the first-floor framing below each low point above it, I would also investigate the reason(s) the higher areas are higher. Here's an example of that: One of the challenges in rehabilitating our old house was that the original builders never heard of the concept of load-bearing. We had to add support in the basement under first-floor walls and remove it from the middle of rooms. More challenging was trying to transfer the support upward and the load downward, since only a portion of two walls upstairs sat on a wall on the first floor. We replaced the ceiling in the front hall at one point, and took the opportunity, when it was open, to install doubled cross-blocking under an upstairs wall, part of which was an exterior wall, that had been framed by laying a single sill plate across the joists - 3' or so from the nearest downstairs "wall," which was, itself, a columned opening some 10' across that had been unsupported in the basement.
One word of caution: Lifting and leveling is done with jacks and timbers that can support and raise many tons of weight. We engaged a professional house-moving company for the heavy lifting in the basement. If you do it yourself, I would consult with a structural engineer first, and Be Careful! It is also sloooow. Adjustments are typically made about once a week, and a raise of 1/4" is heady progress; 1/8" per week is more typical.
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