Author Topic: Options for bump in a floor  (Read 3252 times)

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Offline Deke

  • Posts: 236
Options for bump in a floor
« on: May 21, 2018, 08:06 AM »
I feel like I am taking advantage of the group, but you guys are smarter and more experienced than any home repair forum out there!

Okay, we are going to redo our kitchen. Like every stone house in Pennsylvania, we have some weird dips and angles due to settling. In almost the middle of the length of our kitchen there is a hump, almost certainly over a support beam. I attached a crude image. With a level it measures just under a degree on both sides, but it sure is noticeable when you walk on it and you can actually see it. I could get a longer straight edge and measure exactly ow much it rises/drops across the room.

Right now there is old vinyl flooring. Almost certainly it has the original pine sub floor underneath. We want to pull that vinyl out and put in a wood floor, but maybe some kind of linoleum (as you can guess this is not up to me!). To flooring installers say they can work with it with wood or vinyl/linoleum, bit not ceramic tile. They say we can just deal with it as part of the "charm" of an old house. 

If I really wanted to deal with this, what are my options? Pull out the sub floor and in some way level out a new sub floor? I don't see any way to build UP the parts that are low without causing all kinds of weird issues with the many doorways at the ends of the room. Ah old houses... the fun and $$$ never ends. Thanks in advance.

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Offline tjbnwi

  • Posts: 5761
  • Cedar Tucky Indiana
Re: Options for bump in a floor
« Reply #1 on: May 21, 2018, 08:55 AM »
You can do ceramic, just takes more prep/money.

My guess is the is 1/4” underlayment over the sleepers, under the vinyl. Remove the vinyl and all remnants of the backing. Sometimes it is easier to cut and pull the underlayment and replace it.

At the low point install a strip of plywood of the thickness that levels to the high point. You now have a wedge that can be screeded in with self leveling compound.

Plug any opening the SLC can leak through.

Mapie markets a plastics lath you staple to the sub-floor. Prime the sub-floor with the proper primer, staple down the lath, mix the SLC, place using an inverted bow rack to massage the SLC into place. This process is not easy easy as it sounds to get it right but it is well worth the effort.

If you do go with the hardwood you may just be able to fit strips of plywood, sand edges to blend and use roofing felt strips to shim the floor acceptably flat.

If you go with the hardwood run it perpendicular to the floor joist.

Tom

Offline Brice Burrell

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Re: Options for bump in a floor
« Reply #2 on: May 21, 2018, 09:02 AM »
Is there an unfinished basement under the kitchen that you can look up to see joists/beam and flooring?  You're likely right about a beam being the issue.

I've dealt with this problem many times.  The usual solution is to shim the floor in the low spots.  As you mentioned this can cause issues at doors.  New thresholds to deal with the different floor heights at each doorway is the answer.

I know a guy that believes the answer is to lower the beam.  These beams usually run the entire length of the house and are holding up an awful lot of the house.  I wouldn't take on that task lightly.  Still, its an option to consider.       
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Offline Deke

  • Posts: 236
Re: Options for bump in a floor
« Reply #3 on: May 21, 2018, 09:02 AM »
You can do ceramic, just takes more prep/money.

My guess is the is 1/4” underlayment over the sleepers, under the vinyl. Remove the vinyl and all remnants of the backing. Sometimes it is easier to cut and pull the underlayment and replace it.

At the low point install a strip of plywood of the thickness that levels to the high point. You now have a wedge that can be screeded in with self leveling compound.

Plug any opening the SLC can leak through.

Mapie markets a plastics lath you staple to the sub-floor. Prime the sub-floor with the proper primer, staple down the lath, mix the SLC, place using an inverted bow rack to massage the SLC into place. This process is not easy easy as it sounds to get it right but it is well worth the effort.

If you do go with the hardwood you may just be able to fit strips of plywood, sand edges to blend and use roofing felt strips to shim the floor acceptably flat.

If you go with the hardwood run it perpendicular to the floor joist.

Tom

You are the MAN! Thanks!!! This may have added to our budget (or my work), but it is probably worth it in the end. Oh, most importantly, what new Festools should I tell my wife I need to do this? TS55 would be nice! :-)

Offline Deke

  • Posts: 236
Re: Options for bump in a floor
« Reply #4 on: May 21, 2018, 09:06 AM »
Is there an unfinished basement under the kitchen that you can look up to see joists/beam and flooring?  You're likely right about a beam being the issue.

I've dealt with this problem many times.  The usual solution is to shim the floor in the low spots.  As you mentioned this can cause issues at doors.  New thresholds to deal with the different floor heights at each doorway is the answer.

I know a guy that believes the answer is to lower the beam.  These beams usually run the entire length of the house and are holding up an awful lot of the house.  I wouldn't take on that task lightly.  Still, its an option to consider.     

Thanks, just saw this after my last reply. Believe it or not, the basement has a plaster lathe ceiling covered by a drop ceiling. With the beam probably holding up three floors above it, I'm leaving it alone! :-) I guess the shimming plus four new thresholds is a much better option than doing anything to that beam. Plus the basement is my shop - I couldn't live with tearing it all up. Thanks again.

Offline tjbnwi

  • Posts: 5761
  • Cedar Tucky Indiana
Re: Options for bump in a floor
« Reply #5 on: May 21, 2018, 09:28 AM »
Hopefully with the hump running down the middle of the room, as I picture it in my head this should not affect door openings to much. If it does you’ll have to post pictures of the room, so it can be addressed prior to the work.

TS-55 to cut the underlayment and plywood, RAS or Rotex to blend the edges, don’t forget the appropriate sand paper (got you 2 tools out of the deal).

Tom
« Last Edit: May 21, 2018, 09:30 AM by tjbnwi »

Offline Master Carpenter

  • Posts: 91
Re: Options for bump in a floor
« Reply #6 on: May 21, 2018, 09:56 AM »
I've dealt with floor humps and dips many times. Get a belt sander and knock down the highs. Get floor patch to fill in the lows. Sometimes you have to cheat a little and only get the worst of a hump and feather out the edges with patch

If your doing tile, you'll most likely have to add plywood subfloor to strengthen the floor.
Ts 55, Ts 75, of 1010, lr 32, mft, mfs 700, RO 150 x2 + paper asort, RO 90 + paper asort, pro 5, df 500 + dom asort, hl 850 e, ti 15, t18, cxs, centrotec set, ct48, ct sys, vac sys, 32;55x2;118 tracks, a stack of sys and an og festool first aid kit. Kapex, planex, carvex, conturo.

Offline Deke

  • Posts: 236
Re: Options for bump in a floor
« Reply #7 on: May 21, 2018, 10:44 AM »
Thanks for looking out for me tbnwi, I do have the older smaller Rotex and a RAS, so I guess that would do. I actually had an older TS 75 and sold it. Regret it to this day even though I only used it occasionally.

Master Carpenter - yes, why didn't I think of this. Perhaps I can knock down that a bit with a belt sander. All this has to wait until June when we start, but I am dying to see what is under that floor. Then again, maybe I will die when I see what is under there?

Online Cheese

  • Posts: 5147
Re: Options for bump in a floor
« Reply #8 on: May 21, 2018, 11:34 AM »
If those floor angles you've measured are accurate, then just doing the math means the 9' section will require a 1 1/4" (1.127") spacer, while the 13' section will require a 2 11/64" (2.172") spacer. That's a lot of shim.

The best place to start is removing all the flooring materials so you can see what you have to work with. It's likely that if this house was built prior to the mid twenties, it was common to "overbuild" and the studs and joists may also be full sized dimensional lumber. Meaning, a 2x4 or 2x10 was actually that size. This means you may have extra material in the center beam to work with. Every 1/4" removed from the beam requires a 1/4" thinner spacer at the edges.

Another approach is to not go for the full monty and just reduce the angles by say 1/2. So a .3º angle on one side and a .4º angle on the other. I don't think you'd even notice a .3º angle.

Offline Peter_C

  • Posts: 720
Re: Options for bump in a floor
« Reply #9 on: May 21, 2018, 01:36 PM »
The Festool 2700 or 3000 rail to go with the tracksaw works excellent on edge as a straight edge to judge floor flatness. Definitely going to need a powerful sander for making plywood and luan shims, plus grinding to peak off.

My personal choice in a kitchen will always be tile, and porcelain is about as strong as they get. Schluter Ditra underneath helps decouple it. Wood does "bend" more though. Finished onsite is superior vs a prefinished hardwood.

Please...please NO linoleum unless you want to use it as a shim, which is my preference over asphalt.

A few pictures would be worth thousands of words.

Feel free to ask questions and please don't feel like a burden as these types of questions are entertaining.

Offline sprior

  • Posts: 412
Re: Options for bump in a floor
« Reply #10 on: May 21, 2018, 03:33 PM »
Master Carpenter - yes, why didn't I think of this. Perhaps I can knock down that a bit with a belt sander. All this has to wait until June when we start, but I am dying to see what is under that floor. Then again, maybe I will die when I see what is under there?

Funny you mention dying to see what is under there.  Since you mentioned you are replacing old vinyl you should be aware that older adhesives used for flooring may well contain asbestos - might want to make sure before you go near it, especially with a belt sander.

Offline Deke

  • Posts: 236
Re: Options for bump in a floor
« Reply #11 on: May 21, 2018, 05:48 PM »
If those floor angles you've measured are accurate, then just doing the math means the 9' section will require a 1 1/4" (1.127") spacer, while the 13' section will require a 2 11/64" (2.172") spacer. That's a lot of shim.

The best place to start is removing all the flooring materials so you can see what you have to work with. It's likely that if this house was built prior to the mid twenties, it was common to "overbuild" and the studs and joists may also be full sized dimensional lumber. Meaning, a 2x4 or 2x10 was actually that size. This means you may have extra material in the center beam to work with. Every 1/4" removed from the beam requires a 1/4" thinner spacer at the edges.

Another approach is to not go for the full monty and just reduce the angles by say 1/2. So a .3º angle on one side and a .4º angle on the other. I don't think you'd even notice a .3º angle.

Very smart. That sounds like the way to go. I'll more carefully measure those angles. thanks!

Offline Deke

  • Posts: 236
Re: Options for bump in a floor
« Reply #12 on: May 21, 2018, 05:49 PM »
Funny you mention dying to see what is under there.  Since you mentioned you are replacing old vinyl you should be aware that older adhesives used for flooring may well contain asbestos - might want to make sure before you go near it, especially with a belt sander.

Thanks, it is certainly on the list.

Offline DeformedTree

  • Posts: 208
Re: Options for bump in a floor
« Reply #13 on: May 21, 2018, 08:25 PM »
I have the same situation.  I put down subfloor over the original 1x6 but still there are some bumps and dips.  Plan is to pull the screws used when installing the new sub floor, then in the lows glue in more ply. then get rails and use a router sled to machine it all flat. Not looking forward to this project when I get to it.

It sucks all around and worse is any research into this everyone can't think past SLC and forgets you can't nail down wood floors into that.  No one has developed a Self Leveling material that can then have nails shot thru it.

Online Cheese

  • Posts: 5147
Re: Options for bump in a floor
« Reply #14 on: May 21, 2018, 10:12 PM »
My suggestion would be that rather than trying to accurately verify the angular deviation of your floor, just take a laser level or a chalk line and measure the discrepancy across the entire length at the extreme edges.
This should be pretty easy as you pass the laser level or chalk line across the entire width. The problem with measuring angles is that they vary from joist to joist. What you really want to know is what is the maximum amount of variation at the extremes of the floor.

Offline escan

  • Posts: 45
Re: Options for bump in a floor
« Reply #15 on: May 22, 2018, 09:52 AM »
Recommending structural modification could be hazardous so I'll just answer as if this was my house and I absolutely was not allowed to pad the floor, which is most common. I would leave the beam in place, support the entire floor on both sides of the beam with temp walls, cut the joists vertically in line with the beam, and drop them down to a ledger beam (LVL through bolted with 5/8" @12" on center), that acted as my datum. Once level, I would sandwich the joists above the beam with 2X material, bolted and planed flat.

I've jacked up houses, underpinned foundations, etc.. so I am comfortable with this work, so take your time, have a sound game plan and run it by someone who knows what they are doing. Best of luck.

Offline Deke

  • Posts: 236
Re: Options for bump in a floor
« Reply #16 on: May 26, 2018, 10:06 AM »
Sorry I haven't been around. Thanks to every single person who replied. You have all given me a lot to think about and educated me in the process. I wish I could buy you all a virtual beer, or coffee or something! [smile]

Offline Kodi Crescent

  • Posts: 733
Re: Options for bump in a floor
« Reply #17 on: May 29, 2018, 01:17 PM »
Would it be acceptable to cut the subfloor out over the beam, plane the high spots on the beam, bolt sister 2x material to it, and patch the subfloor?  Am I missing something?

Offline Deke

  • Posts: 236
Re: Options for bump in a floor
« Reply #18 on: May 30, 2018, 06:43 AM »
Would it be acceptable to cut the subfloor out over the beam, plane the high spots on the beam, bolt sister 2x material to it, and patch the subfloor?  Am I missing something?

That could work.

Offline Brice Burrell

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Re: Options for bump in a floor
« Reply #19 on: May 30, 2018, 08:00 AM »
Would it be acceptable to cut the subfloor out over the beam, plane the high spots on the beam, bolt sister 2x material to it, and patch the subfloor?  Am I missing something?

I think that might be part of the solution.  I suspect the foundation has settled leaving the beam and joist high in the center of the floor.  You'd need to remove a fair amount, in not all of the subfloor to plane down the high areas.  That works reasonably well for a relatively small amount of planing.  Of course this assumes the joists are attached to the side of your beam and not sitting on top of the beam (and I believe that is what you since you didn't mention being able to see the beam in the basement).  If they are sitting on top of the beam then you could just cut the joists flat/level. 
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Offline jimbo51

  • Posts: 437
Re: Options for bump in a floor
« Reply #20 on: May 30, 2018, 08:26 AM »
If he levels the floor by cutting down the joists, will this create problems for the doors/entrances becoming uneven to the floor?

A door perpendicular to the beam may be tilted with the floor. The floor near/under the door may have to be trimmed to avoid a trip hazard when exiting the kitchen.

Offline DeformedTree

  • Posts: 208
Re: Options for bump in a floor
« Reply #21 on: May 30, 2018, 11:00 PM »
Would it be acceptable to cut the subfloor out over the beam, plane the high spots on the beam, bolt sister 2x material to it, and patch the subfloor?  Am I missing something?

After I did it all, I wish I had just removed the old subfloor and even replaced joist, then I wouldn't have the issues you have too. 

I don't know where you live, but you can look up span table code for floor joist and see where your floor is.  My house is just 2x8 joist at the limits of span, so concern over modifying the joist is a real concern.  If you are above code on your joist thickness for the span, then you might be able to do as you said.

A modified option is to remove the sub floor, but then apply 1x or 2x material to the sides of your joist that are inline with where you would want the bottom side of new subfloor to fall.  From there, you have 2 options, use these new guides to to the planning of the joist as you said, or leave the joist as is.  If the joist doesn't stick up that high compared to the newly applied side lumber, you could then router a groove down your new subfloor to receive the old joist.  The sub floor will sit on the side material, not the top of the oil joist.   Now this will only work with thick subfloor or shallow groove, otherwise your subfloor will sag between the joist.  But if you only have to make a groove here or there, and have no material to remove from the joist without violating code, this could possibly be an out.

Still, once you got the sub floor out, your are basically there for just full on joist replacement, or sistering them with thicker joist.