I am very near purchasing 1/2" 7-ply engineered flooring to float over concrete in a job near Houston, Texas. Recently, I found 7-ply 3/8" in exactly the right color, etc. I am concerned whether the thinner 3/8" is more prone to buckling, warping, bowing than 1/2". I've looked online for hours now, and it seems that the number of plies is the deciding factor. Since both thicknesses are 7-plies, do you consider them equal? Any opinions? Richard

The amount of ply's don't mean a thing. My fav is a 3 ply any thickness. As a matter of fact I believe to many ply's are bad. Especially if they have a thick veneer on top.

Will there be any noticable difference between using a 3/8's engineered vs a 1/2" engineered product (it will be glued down to cement). I'm trying to decide between the Appalachian Southern Vista 3/8" and the Virginia Vintage 1/2". Is there a difference in feel or in ability to deal with old imperfect concrete floors? It will be glued down to cement, put on wood stairs and will also be laid in my 6" sunken living room so will have to be installed vertical up the 6" concrete footing and be topped off with a stair nosing to finish. Any advice is appreciated...

Ps The wear layer on the 3/8" product is pretty thin compared to the 1/2" product. Both have the Luster Lock finish though.

I think the determining factor will be the thickness of the top layer. The thicker the better.

I've always recommended 3/8" because concrete slabs are rarely 100% level.You can almost always find a hump or a dip in concrete.The thinner the wood is the better it will follow the elevation changes.Take a string and pull it tight from corner to corner,diagonally across the room.This will show you any elevation chances.Drastic humps or dips should be ground down or filled in.This is very important.Without a relatively level surface,glued down flooring will work loose in low spots.I've definitely had more problems with the 1/2" than the 3/8" though.

Unless you have 7 paper thin ply's underneath. Thats called unbalanced construction. The manufacturers got into a contest over the past ten years or so to see who can do more plys, thinking more ply's = more stability. Which is wrong if you throw a thick surface layer on top.

[quote="whattodo"] Will there be any noticable difference between using a 3/8's engineered vs a 1/2" engineered product (it will be glued down to cement).[quote]

[quote="Floorpro"] I've always recommended 3/8" because concrete slabs are rarely 100% level.You can almost always find a hump or a dip in concrete. [quote]

There shouldn't be a difference between installaing 3/8" or 1/2" over concrete. As long as they're installed correctly.
With both thicknesses...
1) The slab needs to be flat 1/4" in 10'.
2) The slab cleaned from foreign matter.
3) Use correct adhesive
4) Correct trowel size, and spread at 45 degree angle
5) Correct flash period of adhesive
6) Rolled with 150 pound roller

Obviously quite a bit more involved to a succesful engineered hardwood installation. But if these points are followed correctly...thickness shouldn't matter, as far as installation.

I agree. This will allow more refinishes in the future.

I believe a combination of balanced construction, and a thick top layer

If you're debating between an Appalachian and Virginia Vintage, both products will have a thin top wear layer, and they will be constructed in an identical fashion as far as the plywood core is concerned, so you won't really have any advantage choosing the 1/2" over the 3/8" thickness.