Subfloor Leveling, Advice Needed

PrecisionFloors

If that were the case, (I've yet to see it though and 70% of the housing in this area is 50's & 60's era) thats exactly what I would propose to do if I were to warranty it. Now if the h.o. wants to sign a waiver in order to keep all of the flooring heights consistent then thats fine too

__________________
Precision Flooring
(772) 237-9900
Tile, Hardwood, Laminate, and Resilient
Installation, Sales & Repair - "We do it right the FIRST time"

nywoodwizard

Haven't herd much on a shimming option , i have in the past pulled up the underpayment of an out of level floor scribed some strips to correct dips in the floor, since jacking any part of the floor was not an option, i believe it was the simplest and most economical fix. I would be weary of putting any leveling compound or equivalent on a wood structure ,i think it only inevitable it will crack, possibly causing a noisy floor or one that may even loosen up if the product crumbles. I took some doug fir 2x4's ripped them to the thickest point and just planed them to zero so they met with the good part of the floor placing them 16" OC ,then installed some 3/4 ply on top it only took a few hours from start to finish.

__________________
Learning without thought is labor lost; thought without learning is perilous.

neolitic

Thereby replacing 1¼' or 2" of solid sub floor with ¾"??

__________________
Put your location in your profile!
(Sorry....it seems there really are dumb questions)

nywoodwizard

Did i miss something ?

He said :"We removed carpet and found 1/2" plywood installed over old solid oak floor. Of course there must be 3/4" or 1/2" sub-floor under the old hardwood as well. So the existing platform is pretty solid."

That adds up to a bit more than 3/4" . He already has a 1/2" or 3/4" sub-floor and the old hardwood floor 3/4. Which leaves 1 1/4" - 1 1/2" after removing the 1/2" found under the carpet and making the repairs, now add 3/4" underlayment ,were up to 2" 2 1/4" then the final layer of hardwood brings us up to 2 3/4" - 3" .

I'm still trying to figure out why anyone would put that last layer of 1/2" on just to install carpet over it.

I personally don't see any reason to leave the old 3/4 hardwood flooring either ,with a floor that has already sagged who knows if the additional weight will make it sag more, and we all know how heavy hardwood flooring is. There is a weight factor here ,and joist size plays the biggest role, adding more flooring won't correct lack of support. This is not going to be a staging area for elephants so i see no added benefits to 4 layers of flooring.

1/2"-3/4" sub-floor + 3/4" underlayment + final layer of hardwood is more than sufficient.

__________________
Learning without thought is labor lost; thought without learning is perilous.

Tileguytodd

If I had to guess (which I actually do)

I would say in all likelyhood based on what I am hearing this is going to be a Single Layer Shiplap boards on the diagonal 3/4" planed or 1" rough depending on builder
1 layer of 15# felt (tarpaper)
the original Oak Hardwood flooring 3/4"
the first remodel's 1/2" Plywood Underlayment.

My first concern would be for HEIGHT of finished floor..Really, check for problem area's like clearances for hot water registers..Doors etc.

My second concern would be the Point Load for the structure....you can fix this and the same thing can happen because of the load and an insufficient joist system. Consider the additional weight that has already been added over the original As engineered floor (which was likely not as strong as todays standards to begin with)

If all structural requiremens are met, there is no reason why you couldnt use Custom RS Self Leveling Cement to fill your low area.
You will seal any holes/seams etc with caulk. You will then Prime and allow to dry 2 coats sealing the wood.
When you pour this not only WILL stick, it will NOT be effected by wood absorbing moisture causing a Curing problem.
This product IS expensive(around 30 bucks a bag(50#) )
It sets up in 4-6 hours but you should allow to fully cure before adding your full spread glue down pad or 15# felt and hardwood floor.

Coverage is around 18 s/f at 3/8"
You will hammer staple 2.5 galvanized wire lathe to your plywood everywhere SLC will be at least 3/16" thick.......the rest will be feathered.

Weve done 100's of thousands of s/f of SLC over the last 8 years and it works very well.
Allow for expansion anywhere you will butt up to an existing wall..Simple 1/4" thick foam weatherstrippijng is fine.
Seal everything well, this stuff will find a pinhole and run through it.
It sets up VERY VERY hard and has a Higher compression strength than your garage floor!!!

__________________
Tilewerks
Tile and Stone Contracting
Warba,MN 55793

1baltic

Thank You, TileguyTodd, and all others.
I poured SLC today. It took 5 bags. Sealed the surface before that of course. Sealed joints with acrylic tile mastic. Tomorrow I'll put down plywood. I was gonna use sub-floor construction adhesive. It is hard as a stone wen cures. Or should I use thin-set mortar instead? We mostly do tile floors, so when it comes to hardwood, a lot of questions arise.
Finished floor is gonna be 1/8-1/4" highier than tile floor in the kitchen. And yes, we'll have to trim 2 doors.
I am sure the structure is fine. The floor is uneven due to removed partion across the room (brick or concrete - I don't know). Somebody did not waste much time to chisel it flush with old hardwood but covered quickly with 1/2" plywood, built few new partitions on top (metal studs) and installed carpet. There are few spots where screws hit a hard surface through existing underlayment. But they are small. It should work.

Jerry T

Too late to help you now. You should have listened to paul and nywoodwizard.

GeraldS

Old post I know but it is one of many conflicting ways of leveling my floor..

Neolitic was right. NYWoodWizard has just changed a solid 2 inch subfloor or underlayment with 3/4 ". By laying shims across the floor where the joists are low and then setting a 3/4" sheet of plywood on top of the shims you now have a gap between the underlayments or subfloors. Now if I was going to lay tile on top of this it wood be insufficient...
He is not laying tile but hardwood I realize but the floor was still compromised using this method. I have been searching and searching for answers to this dilema and thought I had it figured out coming across this site. Seal the subfloor, latex leveling compound to level it out, drop sheets of 1/2" plywood overtop while still moist and screw it down. Has this ever failed anybody? I want a solid floor for my tile and hardwood combination but am worried that the leveling compound will turn to dust. Ahhhh, are there any leveling compounds that will stay solid no matter what? Surely there has to be something out there that can be nailed and screwed through without compromising in the long run.. Putting shims whether it be shingles or planed down 2x4s is simply out of the question for the floor I have come across........

Taranis

Seeing as how this is still current.

I returned to a house I had this issue with 4 years ago. I did the self levelling screed, plywood then fitted a vinyl woodplank (similar to Amtico).
The house is 115 years old.
The ho wanted another room done with the same material as the rest of the floor we laid then looks so good. It has lasted well, 2 children in the house, and no deflection in the sub-floor.
There are many ways of carrying out a job. Do the one that suits overall, not necessarily throw the book at it and rip up half the house cos "it's the best way".

Anyone want pics, just ask.