Leveling a particle board kitchen floor

[Maineman]

Looking for suggestions on leveling the kitchen floor, short of ripping out the whole floor and starting over with 3/4"
plywood, which may be the best option. We are completely remodeling our kitchen, new cabinets, sink, stove etc. so it is
important that we do the floor right the first time.

We have a MH with 3/4" particle board floors, joists are 24" on center. At about 16" from the outer walls the floor has dropped 1/2" in the kitchen. The rest of the house seems fine. The previous owner put a stick built roof over the MH. The extra weight caused the outer walls to sag, taking the kitchen floor with it. We jacked up the entire MH and built a 2x4 stud wall underneath all the outer walls. The MH sits on a 5" poured cement pad that is in excellent shape. We couldn't jack the outer walls up to where they were before the roof was put on but it won't sag any more.

To fix that part of the kitchen floor we plan to cut out the particle board at the first joist, 24" from the outer wall. The joists are 2x6 24" on center and run the full length of the house. If I cut out a strip of the 3/4" particle board flooring in the kitchen, 24" from the outer wall, I will be able to see the sill plate. The sill plate is made of 2 2x6's nailed together for a total width of 3 inches. The particle board flooring sits on the sill plate and the 2x4" outer stud wall (3 1/2" actual) sits on top of that. I figure if I shim out the sill plate with another 2x6 I'll clear the outer wall by 1". I think I will then be able to shim up the top of the 2x6 to the level of the rest of the floor joists, replace the 24" of 3/4" particle board with 3/4" plywood and cover the entire floor with 1/4" luan plywood (1/4" plywood finishd smooth on one side) to cover any seams between the 3/4" particle board and 3/4" plywood. To seal the particle board against moisture, we are thinking of brushing on some polyurethane.

After thinking about it more carefully I think the best bet, althought the most costly and time consuming, is to replace the entire particle board floor with 3/4" plywood and cover that with the finished 1/4" plywood. Someone suggested also covering the 3/4" plywood with 1/2" plywood to ensure that the subfloor would be able to span the 24" joists without sagging. I am wondering if that might be more than I need. I have used the 1/4" finished plywood before in a stick built house on a solid 3/4" plywood subfloor with good results. The company that installed the vinyl flooring recommended it.

Someone else suggested I use a subfloor grade plywood like Plytanium, or similar products. It is very hard and stiff with tongue and groove edges, and it will have its span rating stamped on the back.

Thanks,

Tom

[Harry]

Hi

I agree plywood is the best way to go....and T&G if you can get it.

Harry

[altasnowman]

Hi,
Plywood is good idea,so is sub floor type plywood. T&G style is best and covering with 1/4 luan is good plan. while you have floor opened up check to see if floor joists are not fractured, if they are you will have to repair this before you lay in new floor. best of luck in remodeling your floor.

[Archie]

Agreed, I would replace with plywood. Believe it or not though if you were planning on cutting out a section of the old floor removing the rest won't be much harder, more cost sure, but at least you won't run the risk of the particle board getting soft on you and ruining all your hard work.

I would also use 2x4's to to brace along the walls and in between the joists at the seams of the plywood.