Unlevel Floor

NJDave

I need to install hardwood on a plywood subfloor that is out of level by as much as 1.5" over 6 feet. The subfloor is two layers of 1/2" plywood on floor trusses spaced 18" apart. In the center of the floor there is an interior wall. The floor deflects towards the center wall on all sides. The trusses are accessible from beneath across only part of the floor. I'd have to remove the ceiling to get access to most of the trusses from beneath.

I am considering a number of options including cutting the plywood around the walls, then shimming the top of the trusses and then installing new plywood. I am a little concerned that the existing plywood may be serving to distribute the load from the interior wall and that if I cut the plywood I may cause the deflection to get worse.

I've also considered installing lally columns in the basement but the customer does not want to split up what is now an open room.

Has anyone fixed a similar problem? Thanks

katoman

If you have 1 1/2" fall over 6' you have a structural problem. Is this your problem? In other words are you looking to fix this? If so, consult an engineer.

If on the other hand, you just want to lay the flooring and disregard the structual, I would not cut the plywood. Shim the existing as needed and lay the floor.

Glue all shims so as not to have squeeks. Good luck.

NJDave

This is a condo and the homeowner brought the structural problem to the HOA in the past. The HOA brought in a structural engineer who had plywood gussets installed on the floor trusses as a way to strengthen the floor. The HOA did not want to jack-up the floor to straighten it for fear of causing collateral damage. Seemed like a shortsighted approach, but that's what they did.

CO762

Ouch. So it's not a building issue, rather a design one. Man, don't condo's ****? They're the second worst real estate investment, only behind time shares.

Is there a unit underneath this?

katoman

Well then just shim it out to suit and lay the floor. What else are you going to do? I use PL to glue down long shims like that.

NJDave

No, there's no unit underneath. There's a partly-finished basement under the floor that will get the hardwood.

Shimming may be the only way to go, but shimming 1.5" seems extreme and seems like it may be very difficult to get a good outcome.

Superbird

http://www.ardex.com/productDetail.a...9&ProductID=17

72chevy4x4

are there doors that the 1.5" will mess with? Why can't you just leave it be? maybe with that bad of a subfloor, engineered w/ full spread would be better-you can make it curve better to fit situations as yours.

Snobnd

Unless you glue the floor down - he might end up having a hard time nailing the wood down =4500 PSI ?

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NJDave

The job is being done to prepare the place for sale. The realtor said it would not sell with the floor in its current condition. I kinda agree. You can roll a golf ball across the floor and it picks up speed.