I am looking to install engineered wood flooring over a concrete and wooden subfloor. The flooring is 20mm, engineered wood with tongue and grove system. I am new to this so I have decided to go with floating method.

I am slightly concerned that the glue won't work on the particular floor that I have chosen. The manufacturer says it can be floated but when I look at it the tongue and grove the fit is very poor. There is literally no connection between these two boards; slight movement disconnects them.

The manufacturer has said:

We would expect to see the T and G to look like this, if it is a super snug fit there is no space for the adhesive and this will be forced out when the flooring is knocked together. This way allows the adhesive to stay in the joint, dry and create a strong bond to hold the planks together while still allowing them to move with changes in temperature.

Common sense makes me thing that there isn't enough area for the glue to bind though.

enter image description here enter image description here

For comparison this is a sample from other manufacturer. The fit is extremely tight on it's own:

enter image description here

  • Just a comment here, opinion based: I think you will come to hate and despise the grooves between the boards. They will be dirt catchers and hard to clean. Then you end up with a bunch of "stripes". If you can possibly afford it and installation is doable (worried about the concrete portion), go with solid 3/4" wood of your choice, sand it down once installed (probably a job best left to a pro),, then finish with 3 coats of floor finish and you'll end up with a beautiful, smooth surface which can be re-finished many times when needed ....comment continued below: Commented Nov 7, 2022 at 13:43
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    The other suggestion I have is not to go with T&G, but "click together" sometimes called "snap together" manufactured flooring. I've installed those several times and it turns out great. They hold together with no groves to catch dirt. Also, they are usually floated, so very easy to install. Again, the above comment and this one are just my opinions, but to be honest, there's no way I'd used the T&G products you have pictured. Commented Nov 7, 2022 at 13:47
  • OK...I'm' going to blab on here a bit more. My son just finished a new construction home and used his general contractor to install flooring, he went cheap and got a very inexpensive product. The general contractor (very small company), made several mistakes installing the flooring and now it squeaks everywhere when walking on it. A call to the manufacturer of the flooring informed him that it was not installed according to directions and there was nothing they could do. While more expensive, the best flooring I've installed is LVT, it's water proof, quiet,click together, easy to install. Commented Nov 7, 2022 at 13:56
  • Hello George, So the floor of my selection - is actually quite expensive engineered wood flooring. I think I would like to go with it, but from opnions of others it might be best if I glue it down to the subfloor. I absolutely value your opinion and they are absolutely valid. It's just I like this floor. Is there any reason apart from the "grove" that puts you off these floors? I wonder whether I should glue them down to the subfloor.
    – Taks
    Commented Nov 7, 2022 at 14:02
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    I agree: if you glue it to the subfloor, you do NOT want to be the poor soul who pulls it up later on. I wonder if angle-nailing would do well in this case. An angle-nailer will drive a flat nail at an angle into the upper inside edge of the groove. You can rent pneumatic ones, and once you get the nailer tuned it goes pretty fast. But it would only apply to the portion over subfloor, not concrete. A better solution would be a different floor entirely, but I don't know if you are financially locked in to this one.
    – Smith
    Commented Nov 7, 2022 at 14:45

3 Answers 3


I'm not as concerned as others about the integrity of such a joint. With a good amount of quality wood glue there's a very strong bond formed between multiple faces there. Keep in mind that it's along a significant length that the joint occurs, and the total hold is quite strong. Not all joints are that poor anyway, so on average it's better that that worst-case example.

Here's my prediction for the actual outcome of a well-done joint. Green shows the location and approximate shape of the glue bond.

enter image description here

That's quite a bit of contact over the length of a run, and it's not like the floor flops up and down during use. Movement is miniscule and typically won't crack such joints.

Be sure each joint is well glued and tight on the surface. Use strap clamps for any challenging areas. It'll be fine.

  • Agree 100%. Further point: I'm not sure how tight flooring joints are supposed to be squeezed, but wood working joints, in general, are supposed to be clamped quite tight. This ends up with a glue line that is stronger than the wood around it (multiple tests show that the wood will fail on one side or the other, but not the glue itself). Maybe there's a special "wood flooring glue" that's to be used that doesn't require so much clamping force.
    – FreeMan
    Commented Dec 8, 2022 at 16:31

The floor you've chosen really has a sloppy fit. I've done quite a bit of flooring and have not encountered T & G that fit so loosely. Any slight deviation in your sub floor will result in large gap in the finished floor. I'd think about going with another manufacturer or at least checking to see if you just got a bad sample.

  • Hi Jack, That is why I am surprised why manufacturer says it's meant to be like that..
    – Taks
    Commented Nov 7, 2022 at 13:39
  • If I go with the first floor (which I quite frankly like a lot) do you think I should glue it down?
    – Taks
    Commented Nov 7, 2022 at 13:48
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    Hi JACK (not something I'd say on an airplane! LOL), but I agree with you, they both look like crap. So are they saying you have to glue all that together? What a time consuming mess. IMHO a click-together floating floor is a superior product and easy to install. Best of course is solid wood, sanded and finished in place, but that's pretty expensive. LVT (Luxury Vinyl Tile) is a great product, not cheap, but wow, does it stand up to wear and tear. Commented Nov 7, 2022 at 14:04
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    As @George Anderson suggested , think about LVT. You can get Luxury vinyl tile ( LVT) or Luxury Vinyl planks ( LVP) that look amazingly like that wood and have less expense and easier install with better wear.
    – RMDman
    Commented Nov 7, 2022 at 14:21
  • I agree with @GeorgeAnderson and RMDman that there are better choices but to answer your question, I would not glue it down. Most manufacturers have never put down a floor. :-)
    – JACK
    Commented Nov 7, 2022 at 14:40

That's a nail down floor if I ever saw one.... That's the only way I would set it in place. It is more stable that way, and you don't have to concern yourself the the other requirements needed for laying a floating floor.


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