My situation is a bit odd, so I’ll try to describe my floor. I live in a town home in Tampa, Florida. The home is built over a 4-foot deep reservoir that collects water run off. I’ve since learned that this is a popular design in South Tampa. Looking under the house, I can see the joists with plywood on top of them. I’m not sure how the sub floor is set up, but I’ve been told that there are at least two layers of tarpaper. I do know that my ¾” solid oak is nailed down.

After the recent hurricane season, my hardwood floor is now severely cupped and buckling. This picture isn't the greatest, but you can get an idea in the back rear of the picture where the sun is reflecting (this is by far the least effected area):



I’ve been doing as much research as possible on what to replace this floor with to ensure that this problem does not happen again. I've decided to go with an engineered floor to replace the solid.

I’ve been told and I’ve read conflicting information on how the new floor should be installed. One contractor wants to tear out the existing floor then put down a layer of tarpaper, then a plastic moisture barrier, then a new ½” sub floor, then staple down the new floor over the existing plywood. Another contractor wants to glue down a new floor with basically the same sub floor install. I don’t understand how you can install any of these sub floors without somehow piercing the new moisture barriers with either nails or staples.

I’m hoping that some of you might have experience in this situation and you can offer some advice on what I should look for in the new installation, and what will be best for my situation.

Thanks so much and please feel free to ask any questions on something that I didn't explain thoroughly enough!

- Jeff

The only way that I know of to avoid this from happening in the future is to totally isolate the new oak flooring from the subfloor. The easiest and safest is to go with a floating floor like Kahrs. After drying out the subfloor, simply install a 6 to 8 mil polyethylene plastic film over it. This won't prevent your subfloor from damage but will protect your oak floor. If there is lots of humidity under your home, you should take steps to try to reduce it ( increase vents, fans, vapor barriers, etc.). You could also do with a floating subfloor and nail to that, if you want a solid nailed down floor.

You need to make that 4 foot reservoir, not a reservoir.

The underside of the joist and subfloor have gained significant moisture content!

Is this area under the joists, enclosed?

Thank you for the replies.

Gary - At this point I don't have a preference for how the floor is installed. None of the installers that have been to the house have agreed on what they would do. One said install a new sub floor with tar paper and a plastic film under it, and glue the new floor. One said to install tarpaper and a new subfloor and then staple to the new sub floor. I wasn't aware that you could float a sub floor, so maybe that answers my questions on how they would prevent piercing the moisture barriers.

Floorguy - I agree 100% that this needs to fixed! The joists are in fact exposed under the house. One installer said that he had installed some kind of plastic barrier under a house with a similar situation.

I hoping that you all can chime in with your expert opinions on the best way of installing the new floor so that this situation won't happen again!

I'm hoping that by installing the proper moisture barrier and an engineered floor instead of a solid that this can be prevented from happening again.

Thanks!

Sounds like the plan to me. Slap on some of that Bostik MVP stuff then gluedown or float the floor of your choice.

From The Bostik Site

MVP® Moisture Vapor Protection

MVP® Moisture Vapor Protection is a one-part, trowel applied, elastomeric anti-fracture urethane membrane formulated to reduce moisture vapor transmission from the subfloor, and bridge cracks up to 1/8”, prior to the installation of engineered and solid hardwood flooring with Bostik’s BEST™, BST™, EFA™, Ultra-Set® Hardwood or Fast Tack™ adhesives. MVP may be used over all substrates common to hardwood flooring installations including: concrete, plywood, particle or chip board (underlayment grade), well bonded vinyl, ceramic tile, cement backer board, cement patch/underlayments, radiant heat flooring, and terrazzo.


http://www.bostik-us.com/products/index ... yPageId=34

Thanks Ken. Just so I'm sure that I understand:

This would be applied between my current subfloor and the new plywood to be put down?

Then the new floor would be glued or floated on the new subfloor? Is there a pro/con to using either method?

And lastly, what about stapleing the floor down? One installer seemed pretty intent on that.

Thanks again for all of this great information!

I'm more concerned with rot.

If you don't get that crawl space in check, your joist and subfloor are going to start to rot.

Your installer should have known better then to install this flooring over that crawl space!!! That is his job to know. He should have covered the crawl space soil entirely, with a poly moisture barrier and instructed that all drainage be routed away from the home, before he started the acclimation and especially the installation, or had you sign a waiver of liability before he went ahead and installed that floor.

If you just rip out the existing wood and install engineered, the way it is now, the ends of the engineered are going to raise and peak from the moisture difference between the subfloor and the flooring.

MVP from Boastik's is a great addition to there product line, but in this case, you need to get the subfloor in check first.

Ok guy's, Why is it ok to put Bostik's MVP (moisture vapor retarder) on top of a plywood subfloor and not ok to put 6-mil poly(moisture vapor retarder) on top of the plywood?
I have seen the wet plywood under the poly on some repair jobs we have done because of this. Will the MVP act the same as the poly?
Buddy

Ken - Unfortunately I don't have a choice with the way the home is designed, 17 of the 29 townhome units have this same type of resevoir to collect the storm water. There is no way to avoid it. I know what you are thinking about this being a crawl space, but it's really much more than that since it's four feet deep.

I'll take a picture so you can see what what I'm talking about.

Picture one is the entrance that is on the side of my house. In the lower left you can see a red oval that I added, this is where the storm water enters:



Picture two is the inside of the resevoir area. This space runs under my home, and my two neighbors homes that are connected to me:



So would you suggest some type of plastic barrier be placed on this lower surface?

OK, What you have is called a raised wood subfloor with a crawl space. Since the earth in your crawl space is about 4' lower than the existing ground outside your home, all the ground water is going to collect in your crawl space. You are, in essence, living over a swimming pool. Multiple things need to be done before a wood floor can be successfully installed.
1) Ensure all surface water is diverted away from the home by hooking downspouts to drainage pipe, improve any improper grading, keep sprinklers and drip system away from foundation.
2) Get subsurface water out of crawl space by using a dry well and sump pump that pumps the subsurface water out through the the drain lines you've hookup for your downspots
3) Dry out the earth by increasing air flow. You need more foundation vents and they need to be cross vented. Fans maybe needed till ground dries abit.
4) Cover 100% of the dirt/earth in the crawl space with a 8 mil polyethylene vapor barrier.
5) Once your joists and subfloor reach normal MC (10 to 15%), consider stapling the 8 mil poly to the underside of your floor joists.
Once these steps have been taken and put in place by a well qualified drainage contractor, you should be ready for a wood floor. I think your existing wood floor has suffered too much compression set to be salvaged.
You don't need a new subfloor (not yet anyway) You need to get that water out from under your house. You should be talking to drainage specialists at this point. There are steps that can be taken to solve your drainage problem. Get FIVE estimates before choosing who to hire! Good luck!

So I was reading your posts again and have to wonder; How did the developer/builder of this project get away with such a stupid idea. To use the space under the houses to collect and hold storm water . That is what your saying. The municipality should provide storm drains and all surface water (even from storms) should go in these drains, not under your house. Are you sure that these homes were designed to do this? And what about the homeowners association, what do they say about it? I have never heard of such a thing! But I don't live in hurricane country either. In CA, if your live in an area prone to flooding ( behind a levee next to the river) you build a house on stilts and let the water go where it's gonna go; not collect it under your house. Anyway, I still think something can be done about the water. If not, how do you feel about tile?

Very informative post, thanks Gary!

I don't know much about building homes, but I can tell you that many homes in my area in Tampa are built this way. I'll try and answer all of your questions:


This is what the space was designed to do - collect the storm water. I can't divert the water from filling up this space, it is part of the drainage system for the entire 29 unit complex. There are several of these spaces along the property.


I absolutely agree, and I have brought up this point with the association already. Hopefully we can move forward on it.


This was the suggestion from one of the installers I had come out. I'm glad I got a second agreeing opinion on it!


My wife and I have thought about it, but really love the look of the hardwood.

Does anyone know of a good drainage contractor in the Tampa area?

Thanks again to everyone, all of this information helps more than you know!

That is the weirdest idea I have ever heard. I would sue the builder. Its insane!

I would just let it dry our. Hopefully the cupping will go away and then I would MOVE!

Ya, you need to have a building inspector come and give his opinion on this design!!!


That whole design, and materials used, reeks of rotted wood.



Hardwood flooring, should have never been installed in this home. It was just a matter of time before this happened.

Someone stole your cash to have that put in!

How old is this home and the installation of that cupped hardwood floor?

Who exactly, is blaming this on the hurricane? Was water physically standing on that floor, from the hurricane???


I agree with Ernesto on the lawsuit thing. That is the lamest design I have ever seen, and who is the fool that let this get through building codes?
Florida must be a much different place, to allow that to be built like that!!!

It doesn't even look like pressure treated wood under there!!!

Is insurance paying for this failure?