Subfloor question

[alex351]

Hello,
I had to replace some of the subfloor in a hallway which had 3/4in oak t & g planks which continue out to the living room so now I need to put new hardwood down.
The house has settled a bit and the floor is not very level so when I put down new plywood on the floor joists I noticed some low and high spots and now I am unsure about putting the flooring down.
Is there any material you would suggest for a thin underlayment that wood help level out the surface. The original floor had some kind of brown paper under it.
Can I just install the planks if the floor is not perfectly flat or do I definitely have to do "something" first?
Please advise, I am new to this stuff
Thank you.

[floorman]

If ther are big dips in the floor then you would want to fill those with something.You can either skim the floo r with a floor patch or you can just use tar paper and double it up in the low spots.
You will have some of that with the way the joists are anyway as the plywood will sag inbetween them,but if there are big dips inthere then you would want to do something with that[8D]

Floorman
floorlayers union local 1310

[mrcaptainbob]

Having just removed the subfloor and intalled new joists sistered to the old, I had a fairly serious 'leveling' problem. Since this house house is about 140 yrs old, there's been a lot of 'settling' and sagging that couldn't be handled even with new joists. The one area (14' x 9') was 'dished' from o.oo" at the perimeter to about 2 1/8" at the center. I set up a laser level at about a 4' height and measered the height every 12" on each new joist and transferred the dimensions to a 'map' of the area. I subtracted all the dimensions fom the largest and the results were the 'spacers' needed for a level floor. After cutting them to size on the table saw, I glued them all in place and checked for level. Everything squared up, so I layed two layers of 3/4 plywood down. Checking for level each step of the way. It's rock solid now with no indications (so far)of change. Floorman, do you feel the plywood will still sag even though the spacers are (at the most) 12"? I felt comfy with that, since it's better than the joist 16" centers. The 2nd layer of ply was layed perpendicular to the first. THe first was generously screwed to the floor joists, the 2nd layer is about 50%as 'generous'.

[alex351]

Thank you both for your input...floorman what is a floor patch and would I be able to get it at home depot?
Thanks again

[floorman]

Alex ,floor patch is a cemntitious product that when mixed to a smooth consistancy you can spread on the floor to fill in gaps and voids and wil dry very hard ,but not hard enough you won't be able tosand the roughspots out and make smooth.If you have problem areas you can keep building on top of this stuff to get to the desired heighth.You can get some at h.d. but make sure it is not a gypsom based patch,they are usually white,most manufacturers will not warranty their stuff over it any more cause it has a tendancy to "blow".[8D]

Mr.Captain Bob,i do not expect that you will have any problems with this floor sagging,unless you plan on housing elephants

Floorman
floorlayers union local 1310

[mrcaptainbob]

HEY!!!!! My wife mentioned somethin' 'bout my goin' on a diet, too! Is this collusion? Or just plain ganging up???!! Seriously, thanks for that, Floorman. Hearing from an expert helps put my mind to rest.

[alex351]

Thanks again, think I will do the floor patch thing----it seems like the way to go for me

[floorman]

[8D]

Floorman
floorlayers union local 1310