Concrete to Wood Adhesive

I think that you're going to have a problem with adhesives due to moisture between concrete and plywood. Check here, http://www.thisoldhouse.com/toh/, on the bottom right of page you can post questions. They work on a lot of old stuff and may have an answer. Good Luck.

Bob,

I'm a cynic. I think there's more to this story that you have not told us.

I also think that the ADA, as well as state regulators and relatives of the tennants might be vexed by this, if this is a commercial operation.

And finally, your description of the problem leaves much unanswered. There's the vinyl/plywood interface, the inner ply laminations of the plywood itself, then the plywood to concrete interface. Where is the failure? Can you post pictures?

Have you dissected one of the "bubbles"?

We are just researching the options. This is a result of faulty construction in the first place. We have contacted the contractor that did the installation who is responsible. I didn't leave anything out and this is an unexpected development. We haven't fixed anything yet just trying to get as much information as we can.

You've used the terms buckling and bubbles. I think it will be difficult to ever solve this problem. Ever, without remediation.

Patch one and another one comes up. The wood has been distorted and swollen by the moisture intrusion and will always cause you grief.

Get a lawyer if the house is new, or you purchased insurance for this purpose.

Good luck.

I think you are right on the money. I have decided in my mind that it needs to be replaced and done correctly. Thank you for your comment

Make sure whoever does the work addresses the moisture problem first, otherwise this will happen again. I believe there should be a moisture barrier underneath that slab. If there is not, you may need to go with a completely different flooring system.

Not great news, but there's no point in doing it wrong again.

Moisture problem, hell. Who's the idiot who put 1/4 plywood in here in the first place?

It's not in the rest of the house, is it?

I say take the old folks out for the week and fix it right.

Hi Lyn,

You are right! Before the installation of the plywood, it was absolutely necessary to insulate with 2-pack 100% solids epoxy to impregnate the whole concrete surface and gluing the plywood after with the same epoxy. No neals! The epoxy don't let humidity passes through from the concrete to the wood. One suggestion that can be a solution.

On the actual situation, inject 2-pack very low viscosity but 100% solids epoxy under the floor by saturating the plywood and the concrete as deep as possible, 1/16" to 1/8" deep. It can be done with knowledge and patience, Gil.

One other thing I forgot to add....under most conditions this process can be done over 2-3 days and because it is interior application weather should have little effect....long weekend for the seniors...who would not like that?

I like this approach myself, though foresee baseboard and door issues and still wonder about accomidating the residents. We did successfully painters plastic and thick mil do work in homes where people continued to live. The time spent on making this possible likely burnt up any savings. One client recognized this right away and abandoned any plans to maintain any workable space during our renovation.

There are good reasons that there do exist Certificates of Occupancy, and renovation permitting processes. It is nice to have engineers involved, though they sometimes make mistakes.

I do believe that when I put down flooring on sleepers over concrete the engineer architect did leave expansion room. I also think vaguely that tar paper was involved.

Having torn up many a location I'd about think better of regular old tarpaper than plastic sheeting.

I have no concept at all of 1/4 plywood as anysort of flooring material in any application. Not in my experience.

P.S. Do not run a jackhammer for over one continuous hour at a time. When breaking up concrete start at the outer edges, as they will be the weakest points.

When I remember vaguely putting wood over concrete, and also remember putting mastic down for prefab sections, plus conforming to needs of the client, I feel the rule is don't let the perfect be the enemy of the good, as one of our members uses?

As a worker I have asked the people I was working with, "What's your standard?" There is the producers Triangle of fast and cheap, or whatever it takes.

For the house I worked on with a concrete floor sleepers were used, then boric acid, the maybe an underlayment? Can't remember.

Avantac is very stable, but never have seen it other than 3/4 inch.

Are you sure it is a quarter inch plywood?

In a similar build done from someone who was both an architect and an engineer it was done differently.

Big thing people hate are squeaky floors. Lumps may be hazardous.

Have you checked with your Insurance Policy Underwriter, Agent about what you had better do right away? Is there an order of things within the facility that fixes hazards, then moves to the long term issues, and determines the proper balance of what is imperative, and what can be deferred in the happiest affordable for all resolution to the problem with your floor.

I'm not there.

Send us a picture.

Bondcrete is such an adhesive <http://www.bondall.com/_webapp_5362/BONDCRETE>, however you are going to have problems pulling the buckled timber down to the concrete to glue it!

Bob Vila has this system

It is essentially a moisture barrier. I have used the fancy rubber-plastic-wood ones, but these seem simpler and maybe even cheaper.

His system is great because if (god forbid) there is a problem sometime someday in the future, you can always lift these tiles and deal with any possible problem. Don't touch any underlay which does not give you an air space between the underlay and the concrete.

The downside of such systems is that they rarely if ever ventilate under the underlay, which can and does provide a source for mould. And it WILL get musty and mouldy under there! This step is often overlooked, but considering you have seniors with delicate lungs in there, you MUST treat the concrete with a real sealant, a radon sealant is just barely good enough. Here is one. It penetrates right through the concrete, and is installed in several applications which you should not rush.

Of course...if you had poured the concrete over a proper vapor barrier in the first place, you would not have this problem, but the fact that you get bubbling of the wood means that this not so minor item, which is now code in most places, was overlooked. No biggie. Just pull up the wood, lay down a good silicone sealer, caulk up the cracks and treat the surface with a fungicide before you lay down the underlay. There are some excellent tea tree oil products or you can do what I did and buy several large bottles of tinactin foot powder and sprinkle it on the surface. Can't hurt. Don't have any mould.

If you do that, you probably don't have to do any de-humidifying at all...but honestly, there must be some way to pull the damp air out from under the underlay and vent it outside. I've just never seen anyone do it.

Good morning bobpeters01. Are you saying the contractor thot 1/4" plywood would keep it level when people were walking on it? He had to have known walking across it would be inundating.

Even if you could make the plywood adhere to the existing concrete, it would follow the uneven surface of the concrete, which was the original reason for the plywood.

If it was mine, I would remove everything on the concrete, lay down a thick (10 mil?) vapor barrier, and install 2 to 4" of new, LEVEL, concrete. Then put on top whatever flooring you like. After all, you're only talking about 1 room, the family room, right?

I have never seen anybody do this. Have you done this? It sounds like it just might work.

Good morning Yusef1.

I have never done this, but this is the only suggestion which totally solves the uneven concrete, the moisture problem, the sea-sickness and possible stumbling of older tenents induced by the flexing of the 1/4"? plywood underlayment, all at the same time.

'I was installed on a concrete slab.'

I'm afraid this is usually terminal.

In my opinion you're going to have to replace the old wooden floor with a new one that is Constructed by a reputable flooring Contractor. To try and repair the warping in the existing floor will be futile in the long run, and subject the facility's management to possible lawsuits if someone should trip, fall and become injured due to the tripping hazzards presented by the defects in the existing floor.

After the existing wood floor has been stripped, the concrete slab surface should be acid etched to receive a 2-coat epoxy floor (6 mils minimum DFT). Make sure the epoxy product is meant for application to concrete floor surfaces and is low or non-existant VOC.

Following the curing of the epoxy, install a 6 mil poly plastic vapor barrier atop the slab to prevent migration of moisture from the slab on grade into the new wood floor. Make sure all sheet seams and edges are thoroughly taped with an approved plastic tape!

Good luck with the litigation!

Thank you for input we have contacted the contractor and are awating his response. The floor was actually vinyl he added the wood to shortcut the proper installation. He should have used a concrete leveler and a moisture barrier. Then glue down the vinyl wood appearence flooring. I was not involved in the installation and hiring of this contractor 2 month's ago. I would have stopped work and hired a different contractor immediately. His fix caused the whole project to fail. I question his legitamcy as a flooring contractor. We all know concrete absorbs ground moisture and would transfer it to the wood and the wet to dry conditions that occur would cause the 1/4 inch plywood to warp. Bob

Good luck! I would still consider tile.

I think that is definately a possibility.