Laminate Subfloor

Dorothy · 06-30-2006, 04:48 PM

I'm putting in a laminate floor in an small old two story wood frame house on second floor. The joists are uneven & the floor slopes in places. Without redoing joists how can I level floor. How even/level does it have to be? I plan on plan on placing a second layer of plywood over the first, staggering the seams. Someone mentioned using "self leveling cement". Can this be used in this application? If so, shold it go btween the two layers of plywood? Or where?

Glasshousebltr · 06-30-2006, 04:57 PM

How far out level are the joists?

How old is the structure?

Balloon frame or platform?

If they look real bad I think the best method would be underlayment removal and sister the joists.

Bob

Dorothy · 06-30-2006, 06:05 PM

The house was built in 1972. It orginally was a stilt house (Fla). Sometime in the past the first floor was enclosed. Therefore, I think that it is a platform structure. There are two problems: The joists are uneven and are out about 1/2" in places. The second issue, is that the room was extended out onto a deck, (so the deck became the room's floor.) This area slopes down at the edge maybe an inch in a 3 foot run. We've pulled up most of the old 1/2" plywood subfloor to replace rotten wood and remove low spots. Where the joists were bad we "sistered" another 2x6 where possible. The house is not a square or rectangle, but an odd shape, so some of the joists are at angles to others. We reenforced many of the joists with cross beams. We were considering shimming the edge over the deck, but then found it bows at the center. We were going to put another layer of 1/2"- 3/4" plywood over the first, staggering the seams. We could put in layers of roofing felt, but how many layers is the limit. Where should it go? on the joists or between the two layers of plywood subfloor? It had been suggested that we use self leveling cement, but I have also been told that used on plywood it would dry out and crumble in time. Dorothy

Glasshousebltr · 06-30-2006, 07:28 PM

Felt?...as a leveler....not sure I'd go that route ....in fact, I've never heard of such.

The self leveling, Seems to me if it lasts over luan and under vinyl like it does why wouldn't it last over ply.

I still think your best bet is to go with the sistering method.

If it was built in 72, yes it's platform framing, but how did they come up with 24oc, that has me baffled.

One more thing, better contact the tile manufacturer, I know 16oc requires 1 1/4 sub-strat but 24oc, well like I said better give em a call.

Bob

DaveH · 06-30-2006, 11:54 PM

Hmmm 1972...Odd shape...room extended out on a deck...Sounds to me like a peace and love house. I grew up in a little hippie town and we had these little odd houses everywhere. A frames were very common, as well as octogons, pyramids, one guy had "Aliens land here" painted on his roof. I would follow Glasshouses advice he's the man... I've seen the pictures

Dorothy · 07-01-2006, 03:23 PM

Thanks guys. Appreciate your time & input. I'd hoped that wood laminate would be forgiving enough that I wouldn't have to completely level the subfloor. We've sistered the joints just about as much as possible already, without taking the whole house apart. The house shape has 5 sides. The west wall is 50", the south wall is 20", the first part of the east wall is 20', then runs 30' angling in to meet the 12' north wall. Anyway, this means that the joists in the rooms that we are talking about do not run parellel or even perpendicular to each other, but at angles. Complicating this is the fact that they have been joined together with braces. There is no room to sister some of the joists or even to remove the braces. There are parts of it that look like they were put together by jr. high shop students with scrap lumber & other materials. I'm just trying to make the best of a bad situation. (And yes, somehow it previously passed code.) If you think that the self leveling cement is the way to go then that is what I'll do. Thanks.