Hardwood over concrete slab?

[jlm]

Anyone here have any experiences (good or bad) installing hardwood floors (either solid or engineered) on a concrete slab (fully cured, above grade)? LOML's newly-acquired house is going to need new flooring throughout and she's gung-ho about real wood floors. Laminate isn't an option (it's an older home and we'd like to keep as much "old-house" character as we can, so plastic flooring isn't too desirable), so I'm looking at all the options in engineered and solid hardwood, trying to find a good solution.

The traditional, "nail down plywood or battens and nail the floor to those" method would raise the floor something like 1.5", which seems like a poor solution. There are systems from Junckers and others that use thin steel rails attached to the floor and clip the solid planks to those. Clever, but expensive.

I'm leaning toward a glue-down or floating engineered floor, but most I've seen either look cheap or have a very thin top veneer, making me wonder about durability. Ideally, I'd like to do the install myself (I've installed glue-down parquet floors and click-together engineered cork, as well as refinished several traditional hardwood floors, so I think I'm pretty aware of what I'm getting into). Any product recommendations or things to watch out for as I shop around?

Also, what about bamboo? I've seen some really nice-looking solid bamboo planks, and have been told you can glue these at the tongue-and-groove to make a floating floor. Has anyone here done this?

[steve-norrell]

We had hardwood (birch) installed in the upstairs (nailed down to wood sub-flooring) and in a very small section down on the concrete floor of the lower level. The lower level installation had to be glued down and the manufacturer said it would not honor any warranty on the glued-down part.

We also had some laminate installed over the concrete slab, with a foam sheet between the laminate and the concrete. It came out quite nice and we are going to have another room done. The only downside, IMHO is that the floor tends to be colder than either real wood or carpet.

The laminate is a high-end Mannington product in a stone tile (rather than wood) pattern. I would recommend it but caution that you will get only what you are willing to pay for.

Regards, Steve

[pelligrini]

I don't follow the slab above grade part. Is this a suspended slab or something?

We had a builder not follow our specs and glue down a wood floor on a slab on grade. He didn't put down the Laticrete membrane on the slab. He said there was already a membrane under the slab. Later that year he replaced the wood in all of the first floor installations.

We used a pre-finished 3/4" birch floor in a recent condo project (not on concrete though). I would echo Steve's recommendation 'you get what you pay for'. They skimped and got a really cheap material. You can almost sneeze at it and it will start cupping.

[jlm]

By "above grade" I guess I meant "on grade" - meaning, it's not below grade in a basement.

And yeah, I can see the difference even $1 per square foot can make in the different options I've looked at so far. That's why I'd like to do the work myself - if I can save a $3/sq ft installation charges, I can spend that money on getting a nicer floor.

[dkhoward]

I have some high end engineered lock together floating laminate in my dining room, entry way, and breakfast area. I did the install myself and it was rather easy. Watch the subfloor membrane. Get the really good stuff and don't scrimp on it. It makes all the different in the world. Follow the directions carefully, plan your layout and take your time. We have two large dogs (80lb dobie and a 75lb greyhound) who live on this floor most of the time. Other than the obvious issues they have with the slick surface, we have not had any issues with abnormal wear or marking. If these two cant ding the surface, it is pretty tough.

[crokett]

There is bamboo you can float - I looked at some from Costco last year but did not buy it as the interior decorator didn't like the color. You can also glue it down.

[JR]

There is bamboo you can float ...

I saw some at the Depot two days ago. 9/16" thick engineered, click together. It's for my upstairs office, so I think it may be sufficient, otherwise I'd want thicker/solid.

JR

[Anna]

Do a good research on bamboo online before you decide to use it. There seems to be a lot of problems with bamboo floors, including being easily scratched. Lots of unhappy people out there. Apparently, there are several grades of bamboo, and the older woods are supposed to be harder. I think a lot of the cheaper ones for sale are three years old or younger, and just pressing your fingernail on them will produces scratches and dents, not to mention walking on them or dropping something.

The good bamboo floors approach the price of other hardwoods, so I don't really see any upside besides the looks and the fact that it's a renewable resource.

But I don't have hardwood floors, so what do I know.

[gabedad]

we had engineered hardwood put down in our kitchen. We have a slab with radiant heat. So far so good.

[Mr__Bill]

One word of caution, whatever you use, the likelihood that the concrete slab is flat is rather slim. The hills and valleys will result in voids under the flooring that will make for strangeness in the final floor. The carpeting that is usually installed over a slab hides this and tile layers correct for this as they lay the floor but for wood you have to do it as a separate step.

Good luck with the project and let us know how things turn out.

Bill, on a foggy rainy Oregon Coast

[Alex Franke]

Here's a thread from when I installed bamboo over concrete. Lots of good info in there, too.

http://www.bt3central.com/showthread.php?t=34097

[jlm]

Here's a thread from when I installed bamboo over concrete.

So how has the floor held up for the past few months since you installed it?

[JimD]

I put laminated oak flooring, 3/8 thick with a top layer about 1/8, in our basement several years ago. I glued it down with a smelly solvent cement recommended by the manufacturer. I put the glue down and combed it out with a v-notch trowel. It was messy and a bit smelly but the final product is fine. I dropped a ceiling fan and dinged it but otherwise it is holding up well. The center layers are poplar so I think it was more easily dinged than solid oak would have been but you shouldn't drop ceiling fans. The glue seemed flexible enough that I do not see a reason for a membrane and the flooring manufacturer didn't recommend one. Our basement is dry but is probably still a more demanding application than you describe. The rear wall is at grade but the front wall is 5 feet or so below grade.

Jim

[jlm]

JimD,

Do you happen to recall the brand flooring you installed, and which glue you used?

[cgallery]

There was an episode of Holmes on Homes recently (I'm sure it was a repeat) where they had a kitchen with a wood floor on top of concrete. The contractor put down a layer of plastic, then a layer of plywood, then the floor. At least, I think that was the order.

There were terrible problems w/ the floor. It had been replaced twice and was going bad again.

They never really concluded (I don't think) what was causing it. Putting down the plastic apparently was a no-no, but I don't know what the difference between plastic and foam padding (for a floating floor) would have been.

Whatever you do, talk to some manufacturers and ask them what they will warranty for floors on top of concrete. That will give you a good indication for what they have tested and found to work.