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leveling a concrete slab

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I want to install an engineered wood floor over a slab. I took a 4 foot level to see high and low spots that need leveling before installing the floor. As expected I found several areas needing work- despite the fact that visuallly the floor looks fairly level. I'm talking about maybe 1/4- 3/8 inch variations. I Know there are various compounds top used to fill the floor. I'm looking for the best technique to use to actually level the floor. For example , do I divide the floor into section with a snap line so that I can systematically assess and fill each area? What's the best approach here.

 

Thanks for the help.

Mark

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why not put your wood floor on top of some sort of cushion. You're not gonna feel the "squishiness" through the wood floor unless you put some 2" foam in there. it will fill up the gaps and level for you... if not you could always mix up some mud (cement) to fill up the low spots.

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I used Level-Best floor leveler I believe it was called. Used it under the floor in my living room where we used a engineered floor and in other areas like the laundry room under linolium floor. Had a long 7-8' straight-edge that had a metal edge on it. I do not know where we got it, but it was left over construction piece and it was straight. Would mix up a batch in 5 gallon sheetrock bucket using a 1/2 drill and big paint mixer bit and then pour it out and work the straight edge back and forth in one direction, which would move excess material out in front of the straight edge. Seemed to work out okay. Sort of like what you would do if you were building a concrete sidewalk and used a straight edge between the forms - believe it is called a concrete screed.

 

Good luck.

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Are you looking to level the floor or just make it flat? Unless your building a bowling alley or something I think you want it flat.

 

If what your looking for is a flat floor the technique described above is solid. Use as long and as straight a screed as you can find. I like to mark the offending areas with lines. screed it off (the rental house near me rents 10 footers). It will require some troweling but do not over work or over pressure the trowel. If that scaries you, there are self leveling compounds but they tend to be messy. A company called ARDEX (google search) makes many different types of products.

 

good luck

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if your floor is a 1/4 off dont worry you would not even notice it after the foam is layed down and the wood. 1/4 3/8 is pretty good. but if it bothers that bad. buy some self levler in home depot. mix it an pour it fills all the low spots. but i would not worry about it. i do this work every day and i thank god if a floor is an inch off

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lots of ways to address this one. I had a slab that was 3.5 inches off level, and had to have a contractor come in and pump self-leveling gypcrete. You can do the following:

 

-build up the depressions with layers of roofing felt

-buy bags of gypcrete from Lowes or Homies (it is in the flooring section, not concrete)

-use two layers of foam under the flooring instead of one

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Some of you refer to foam. the underlayment material that was suggested is extremely thin less 1/32 of an inch made of rubbber with a plastic vapor barrier.Do you mean this?

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Hey RichG-

how expensive is it to have someone pour in self leveling gypcrete? Is it priced per cubic yard or by the job?

Thanks

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Are your height variations low spots, high spots or a combination of both?

Extra layers of foam are still going to conform to the floor contour, so it's not really going to solve your problem. I assume you are using a floating floor like Pergo?

Find the highest spot and feather it out as wide as you can and fill the low spots. This should get you really close, where it won't matter.

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Streching a string from wall to wall may give u scary results.

Normally the block perimeter will hold up the outside edges while the center over time will drop from the weight of the slab.

I call it ship bottom as the sway back floor more resembles a boat hull than the horizon on a flat calm day..

Covering it with wood won't tell u the whole story so u should be fine.

Tile with it's grout lines tells all the little imperfections..

I get asked to do tile work over concrete all the time.People think its nice an flat.It's the worst hills, valley's.To fix the little stuff i use a feather edge.it's what we use for mud walls.It has a thin 5/16" edge which is nice as it does not drag to much material. u can just get a piece of aluminum angle.About 4-6 ft is plenty.U wanna do little area's..If the slab is clean u can use plain thinset.It is abot 1/4 of the price of the leveling materials.If it has some old glue residue get some thinset with the latex additive.

Flat trowel it to the slab for a good bond then pull the area off.This helps me dramtically an many times is well worth the day watsed so I don't have to pad tiles up all day long.

There are many other ways to make a floor flat.the self levelers have there applica's as well as mudding it to make it perfect.I think for the wood all u have to do is fix some of it an u will be OK>..

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wait, we gotta back up here. check with the manufacturer before you put engineered wood on a slab. some brands are glued, nailed or floated. you may be looking at laminate (ie pergo)

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Ckeck out laminatefloorscheap dot com and give the guy a call, he was very helpful with me when i did the floors in my place. His flooring is the best and his prices are great & free shipping to your door.

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Its' not a pergo type laminate. Its' engineered real wood. Another problem is that when I removed the old carpet I found a thin tile underneath which I also removed. But under that tile is a black subtsatnce , probably glue, that adhered to the surface and does not appear to be removable. Now I'm concerned that I wont get any adhesion when I spread out leveling compound.

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