Leveling a sub floor to lay HW down

[Kevin Murdock]

All,

I did a search on the net for tips on leveling a sub-floor in preparation for laying hardwood. Saw a few places where roofing shingles were recommended to build up the low spots.

Has anyone ever tried this? Have you ever had to stack them in a larger low spot? I know that laying roofing felt down as a vapor barrier is common practice, and I've done this myself when laying HW on the 2nd floor of my house. Even folded some cutouts to shim small valleys when needed.

Now I'm getting ready to start prep'ing the 1st floor of my house and was looking for methods that creekers use to get the sub floor as level as possible. I've got a few dips in a room that are little too deep for my liking. But I'm not sure if I want to lay down the concrete level compounds that you find at the home centers so I'm looking for alternatives from the experts.

Thanks,
/Kevin

[Jeff Sudmeier]

I have used shingles in the past. They have worked great. The main reason we have used them is to avoid squeaks....

Unfortunately, we have only used them in remodels for customers, not friends, so I don't know the longevity.

[John Pollman]

Kevin,

I just finished installing about 900 square feet of hardwood for a customer. About half of it was in the old portion of the house and the other half was in the brand new addition. The portion in the addition was no problem and went smoothly. But in the old portion of the house there was one spot in particular that was a problem. There was a dip in the dining room that was maybe 2' accross. It was kind of a bowl shape. I laid down my 15 lb. felt and then worked my way up to near where the low area was. I then just took my 4' level and laid it down over the area. I could then see how low it was and where. I then just proceeded to use come cedar shims that were about 1.5" wide. I laid them out in a fan pattern. I just worked them until I was fairly level and then just tacked them in place with my brad nailer so they wouldn't move around. I then proceeded to lay the 3/4 oak as normal and things worked out fine. Again, I just finished this job about three weeks ago but I don't forsee any problems.

I also installed about 1200 square feet of solid hardwood for my next door neighbor this past summer. That job was a nightmare ! Had to match old with new and the old portion of the house had sunk about 3" ! We ended up cutting a bunch of long shims out of 2x4 to tack on top of the joists and then put new 3/4 plywood over these "sleepers". But where that patch ended and had to meet up with the new and old subfloor I just used the cedar shim technique and it worked out fine. I finished that job in early September and no problems yet.

I think the shims will work fine for what you need to do.

Good luck !

John

[Chris Padilla]

Hey John,

Nice avatar...too bad about this year, eh? :) sorry for the OT....

[James Stokes]

I have put down a lot of hardwood floors over the years. There are several ways to level an old floor, the concrete patch is good but some of that is hard to nail through when it is thick. Ceder shims work good but they leave you with hollow spots, not a real problem with 3/4 floor or you can use sand, ( I know sounds cheesey but it actually works pretty good.) Before you lay your felt find your dips and take fine sand and level. Put the felt over that and lay the floor as you normally would. The sand will level out by itself if it is not real level. I have used this method many times over the years and have never had a problem. It is quick, easy, and works.