I am installing an engineered hardwood floor over a concrete slab (Mannington’s Jamestown Oak plank). Actually, I am having it installed. There are basically two ways to have it installed;
glued down directly to the concrete slab, somewhat like tile,
a “floating” installation, where cushioning and vapor barrier is laid down and the wood planks are glued to each other, but not to the floor.
The place where I bought the wood (and arranged for the installation) told me only about the glue down method and did not offer any options, but it seems to me that the floating installation would be better (a little more “give” to the floor).
No experience, but I’m looking to do the same thing, but over a plywood subfloor. If you don’t mind, I’d like to tack on a question:
I am having it put in a long, narrow-ish room; approx. 30’x 12’. The main light comes from windows on the long side. I’ve read that flooring looks better parallel to the main light source, but I’ve also read that you should install it perpendicular to the floor joists. Does that matter over a good subfloor? I’m afraid of my room looking like a bowling alley if we do it the long way.
I installed a floating floor a few years back (concrete slab here). I’d say a few IMO things. The floor needs to be FLAT. There is a low spot in that room about 2 feet across and probably only something like 1/8 of an inch lower in the lowest spot. Every time you walk across that area you can feel/hear the floor being pressed down. It I had a solid hardwood floor I wouldnt be to worried about it. But for the engineered hardwoods the stuff under the veneer looks to me to look like glorified particle board. Many flexing cycles on that stuff worries me.
So. that cushion stuff doesnt do diddly for a wide low spot. Also, any upwards bumps are also BAD IMO. Lets say you take a hammer and hit the floor, knocking out a small chunk of concrete. The floor will span that fine. Now, lets say you put a small blob of concrete only a few millimeters high. That cushioning IMO ain’t gonna compenstate for that .
So, IMO the floor needs to be pretty darn flat AND have NO high spots. But that’s just me. The SO let me kill all the high spots but she wouldn’t let me float the floor with leveler to get rid of the low spot.
Oh, and you need to make sure all those grooves are cleaned out before “clicking them together”. If there is any crap in there (and there will be some in some pieces) the pieces won’t interlock as tightly as they should and you’ll have some minor gaps were there shouldn’t be any.
I would recommend the floating floor method on a concrete slab for various reasons:
1.) Installation is easier, much faster and, with some flooring, no glue is required.
2.) You require a vapour barrier between the concrete and wood to eliminate the transfer of moisture which will damage the wood and allow for potential mould growth.
3.) During installation, there is some play and previous work can be corrected and the whole floor can be “tightened up” as one piece.
3.) Gluing the engineered flooring down will not allow for the contraction or expansion of either material.
4.) The glue and/or concrete may break down over time and lose their bond.
5.) Future repairs, removal and/or replacement will be much easier.
As billfish stated, the floor need to be almost perfectly flat to avoid the “bubble” effect. This can be achieved with a thin coat of self-leveling concrete.
We just had a floating floor installed over concrete. It isn’t glued together, it’s a tonge and groove kind of system that sort of clips together. Our floor isn’t that flat, and we have no problems.
I installed an engineered hardwood floor in my basement. It is a very high-quality flooring material, comprised of hardwood laminates and a 4 mil wear layer made of oak. It looks great. Because it was going in our basement, I took moisture into account with the design of the subfloor. Here’s what I did:
Cleaned concrete floor. I did not apply a sealer.
Laid down a high quality landscape fabric.
Laid down Delta-FL moisture barrier. This is a dimpled plastic membrane product that allows water vapor to flow underneath it. Platon and Dricore are similar products. Overlapped edges were sealed with tape recommended by the manufacturer.
Laid down AdvanTech sheeting. This is the best sheeting you can buy, even better than traditional plywood. It is very strong and *extremely *moisture-resistant. I screwed the AdvanTech into the concrete floor using 1/4" x 2-1/4" Tapcon screws. Just before drilling, I dipped each screw in caulking. I used approximately 15 screws per 4’ x 8’ sheet of AdvanTech.
I stapled the hardwood floor to the AdvanTech sheeting. I did not use any glue – just staples. The manufacturer of the hardwood floor was very specific on the size of staples to use. (If you use staples that are too big, it will end up cracking the tongues.) I purchased a $300 pneumatic stapler just for the job.
This advice sounded good to me (I expect it is good) and I went back to the installer and asked about it. I basically assumed that it would be approximately the same price. I was wrong. The original price for gluing the floor down was $2.70 a square foot. The price to float the floor was $3.50, which translated to about $800.00 more for me. My product requires that the edges be glued to each other, and apparently this is more tedious (and time consuming) than simply laying the mastic down on the floor (or so I am told). In any case, I decided to simply glue it down. I don’t expect to live there for too long anyway, so I think this will be fine.
Thanks for your time.