Can I glue-down AND edge-glue my engineered wood floor?

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Hello all - this is my first post, and I'm a novice, when it comes to flooring installation, so please forgive my ignorance.

I recently installed a 3/8" engineered wood floor -- over a concrete floor (elevated, not on grade) -- as a floating system, on a foam acoustical underlayment. It's a click-together system.

It sounds terrible to walk on - a mix of hollow thumps, and crackling rice crispies.

So, I'm pulling it up, and gluing to the slab with an acoustic adhesive (Sika T21).

My question (and I've done a lot of searching for an answer - but can't find a thing) -- is: Since I can't go back, after the flooring is glued down - can I also glue the tongues/groves of the boards to eliminate noises? I bought a bunch of Titebond tongue and groove glue, in case the answer is yes.

I know that expansion and contraction is the concern, but I'm thinking that the whole floor will expand and contract as a system, if I leave enough gap at the edges?

The rooms are small (10'x14') and the high-traffic areas that I'm most worried about (kitchen and hallway) have very short runs -- boards that are only 4' long (running perpindicular to the space).

Any advice is greatly appreciated.
 

Mark Brown

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There would be no benefit to gluing the tongues. There is no movement on a glued system. I just did my floor at home yesterday, on a wooden subfloor I still opted to glue it because it is an engineered and for the same reasons you outlined I do not like to nail them. I did not even ponder gluing edges, only because there would not be a need or benefit. I do like your thinking though. Unfortunately, your floor when adhered to the substrate will not move as a single entity even though the whole structure will be subject to the same conditions and move in unison. The same is also true with floating floors. There is nothing on the planet that will stop the molecular change in wood subject to environmental conditions it is in. One thing you can do.... glue it all down. Silence truly is golden ;)
 
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Hi Mark. Thanks very much for your quick reply. I really appreciate your time and insight.

I am hopeful that glueing everything down will do the trick -- I would just hate to discover later that the click-joints still make noise. I don't mind the extra time and expense of edge gluing, as long as I'm not setting myself up for some kind of catastrophic expansion/contraction failure.

I'm guessing that it's at least safe to do in the short-run areas?

Is there any chance it would help to shave the click-notch off of the tongues, so they behave more like tongue-and-groove engineered flooring? Although -- I can't find any mention of anyone ever double-glueing a tongue-and-groove floor, either.

Thanks again.
 

Mark Brown

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I can't say I have any real world experience with it as far as a wood floor goes so I would be guessing either way but in still going to guess it would be pointless.

The only anecdotal evidence I could lend would be the fact that I have full spread quite a few click lock vinyl floors in the same fashion of what you are suggesting now and I still did not glue any tongues. There just should not be the movement to facilitate sounds at that junction.
 

C.J.

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Why not just install the floor floating style while gluing the T&G? How about the flatness of the slab? I got questions before I give my blessing.

The noise is from movement between the individual planks. Glue down will eliminate that movement but in theory so will gluing the T&G because that will also eliminate movement between the individual planks

You mention hollow sounds and crispy sounds. The hollow spots are most likely because your floor isn’t flat. This will also be an issue for a glue down install. You will have to do something to ensure the boards make, and maintain, contact with the adhesive until it sets up. Weight down the hollow spots? Or how about just making sure the slab is flat first. The crispy sounds are likely some crap underneath either the floor itself or the underlayment. So in theory if you corrected the flatness issue and cleaned up any garbage underneath the floor, it should be a completely different installation experience.

Did you use a vapor barrier underneath the floor and underlayment? What is the atmosphere (relative humidity) like in the basement. Both of those will affect a wood floor. I would hate for you to go to all the trouble and expense of doing a glue down installation and still have issues. Much better to solve the issues that you have and maintain the floating installation than to band aid over them with glue and still have problems down the road. Just some food for thought.
 
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highup

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And they do make adhesives with moisture limiters built in them. Even though it sounds dicey the manufacturers of the adhesive our big companies not fly by nights.
I live in the land of wood framed housing. If I had a concrete slab, I'd be asking questions too.
What C J said about being sure that the slab is flat is very important.

.....extremely important.
 
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Hi C.J. and highup -- thanks for the responses.

It's not actually a concrete slab that I'm installing on. It's a precast concrete plank system (tongue and groove, ironically), so it's pretty flat to start with -- since the planks are made in a factory, not on-site. Then it has an ardex self-leveling cement topcoat, on top. Pretty flat.

I'm exaggerating on the hollow sounds -- it just not the sound of walking on a firmly attached floor. I am getting a good bit of crackling though. It's amazing how much flex this thin layer of floor muffler has.

I've made a couple of sample boards with glued edges, then glued them down. Rock solid. Think I'm going to go that route.

Seem like I'll be the first person to ever edge-glue and glue down?
 

Mark Brown

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Full spread adhesion is the win in my mind for anything that is modular. I do not like floating hardwood, laminate, vinyl plank well you get the idea. Hell there is even floating carpet tile and I think that is dumb too!

I like your curiosity, its infectious.
 
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