Leveling plywood

helpless handyman

Hi Everyone,

I have an old house that I would like to try to level the wood floor, before finishing the floors. I have floor boards nailed to the beams,(its like the subfloor, but don't want to remove it, labor cost, dumpster to dispose material, etc.) and I took of a layer of tongue and groove boards off, that were on top of the floor boards. I don't want to remove the floor boards, but instead I want to lay 3/4 plywood on top of the floor boards, and level the plywood as I go. Whats the best way to do this? This is the main floor, living room, dinning room, and kitchen. They are dips on the floor, due to age on the house, if I start ripping beams out, I will run out of money, Thanks I want to lay hardwood floors on the lR and DR, Kitchen will have ceramic tiles. I will install wonderboard in the kitchen area. Thanks

redline

How much are the floors off?

helpless handyman

Thanks, the floor has some high spots and low spots. I haven't checked to see the actual amount is off.

redline

Is there a full basement under these floors?

helpless handyman

Yes there is, 15' X 36', ceiling height about 6'3". Thanks

redline

I would look in the basement and see why the floor joists are sagging. You may take the time to try to level the plywood on the floor but the floor joists may continue to sag further. Find the problem with the sagging floor joists and try to correct the problem from below. You may need to install joists hangers or reinforce the joists if they are cracked or have other problems. Once the floor joists are more level and stable then proceed with the floor from above.

dougrus

I agree with redline. Investigate...make sure the joists are ok.

If the dips, etc arent bad and really are not from significant joist sagging, you can use Self Leveling compound...if you are using cement board use a portland cement based leveling compound.

__________________
Doug Russell

"What if the hokey pokey really IS what its all about."

helpless handyman

Thanks Redline and Dougrus. I will check. The joist spam from one end of the house to the other, 15ft distance. The house was built in the 1930's, and I beleive the joist have dips or bows on them, with all the years and weight on them. They sit on a concrete edge and run from one end of the house to the other. You see some high ends at the edge of one part of the room, then they bow down slightly. Also I beleive that the floor boards probably have dips as well. I was wondering if I should remove the floor boards, and sister joist the beams to bring them to leverage, but that will be a project and half, ripping, dumpster, materials, etc, headaches. Just looking for advice.

redline

Why can't you put a 4x4 under the floor and support it with a floor jack?

The floor joists may have been under sized or spaced for todays heavier furniture and other "stuff".

helpless handyman

Hi, I just had a steam pipe from my boiler moved to the side of the room, and I don't want to take up space in the basement. I would like to finish it up nicely in the future. Thanks. Installing 4x4 will obstruct my plans.

KUIPORNG

but if you need to you need to, it is more important for the structure to be strong ... you need to change your plan if there is really sagging going on... may be you can install somthing like a horizontal bar and two supports to get it out of the way... but you need to fix the sagging...

Bonus

What size are these joists that span 15'. 2x?

helpless handyman

Okay, I checked last night with a leveler, and I am off not that much. The whole floor is not sagging, theres just dips in several areas. The joist are 2 X 8, the entire house is made of 2 X 8, built in the 1930's. I know it should be 2 X 10's for the span. But the second floors weight does not sit on the first floor joist, I checked it out. I guess wood was expensive back in the days. Thanks

dougrus

Maybe you already said this but I couldnt find it.
Are the joists 16 on center at least?

__________________
Doug Russell

"What if the hokey pokey really IS what its all about."

Hammatime

You could raise the joists up so they are level then sister another 2 x 8 to the existing joists.