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Suzie02
Hardwood floor over concrete ( not basement)

Hi Everyone.
I have read several of threads here on the sight regarding installing hardwood floors over concrete. Most say not to it and if you do, you need to seal the concrete first. All of these inquiries relate to installing in a basement. I would like to install part of my hardwood floor over concrete. However, the concrete is an old back porch slab that has been incorporated into the house and is now part of the dining room/ kitchen area. The part I need to lay the wood over is in the middle of the house ( nowhere near an outside wall) and has a zero percent chance of having moisture seep up.
Here are my questions:
Do I have to seal the concrete? ( if so, what is recommended?)
How do I attach the hardwood floor to the concrete? ( liquid nails?)

Thanks in advance for the help.

A. Spruce
Re: Hardwood floor over concrete ( not basement)

I would use a floating floor system. Floating floors do not attach to the substrate, hence the term "floating'. Typical installation of a floating floor over slab is to lay down 6mil plastic sheeting with seams having a 3' overlap and fully taped, 1/8" foam pad with fully taped seams, then the flooring. Be sure to leave a 1/4" gap around the perimeter for expansion. Baseboard or base shoe will cover the gap.

If the concrete is rough or uneven, then I would smooth it with thinset or floor leveling compound before laying the plastic.

jkirk
Re: Hardwood floor over concrete ( not basement)

basically what he means is that real hardwood wont work, your looking at either engineered hardwood or laminate

real hardwood has to be fastened down

A. Spruce
Re: Hardwood floor over concrete ( not basement)
jkirk wrote:

basically what he means is that real hardwood wont work, your looking at either engineered hardwood or laminate

real hardwood has to be fastened down

What, didn't I say that? ;):p

My preference is engineered flooring - Kahrs is one of the best. Laminates aren't all that durable, particularly in an environment with heavy traffic, children, or animals.

jkirk
Re: Hardwood floor over concrete ( not basement)

i completely agree, around here myself and some colleagues have dubbed laminate as de-laminate. as it pulls apart.

if laminate gets scratched you see a large white or green line, if engineered gets scratched it looks like a hardwood floor that gets scratched, also engineered can be refinished, laminate gets thrown out

A. Spruce
Re: Hardwood floor over concrete ( not basement)
jkirk wrote:

also engineered can be refinished, laminate gets thrown out

Sometimes yes, sometimes no. A good engineered such as Kahrs has a nice thick finish layer that can be refinished a couple of times, whereas Bruce engineered flooring has a paper thin wood finish layer and is not refinishable, or at least you can't sand it. IMHO, when installing any flooring, it is best to go with the absolute best quality that you can afford so that it will last you many many years.

Suzie02
Re: Hardwood floor over concrete ( not basement)

Thanks for the advice. I should have mentioned in the first post that most of the floor will be nailed onto a wooden subfloor.
For instance:
I have an 8' piece of unfinished hickory, and the last 2 feet will be
on top concrete while the other 6' will be nailed down.
What can I do to ensure the 2 feet on top of the concrete is secure?
Do I allow this part to be floating or do I stick it to the concrete with an adhesive?
Once again, thanks for the help.

A. Spruce
Re: Hardwood floor over concrete ( not basement)

So you're using full thickness flooring? Then you can't do a floating floor because it has to be fastened down. I've never done this over concrete, though I've seen others install 3/4" plywood over the slab with nails and glue, then nail the hardwood down to that.

If it were me in this situation, I think I'd end the flooring at the doorway and install floating floor over the slab.

jingreenville
Re: Hardwood floor over concrete ( not basement)

I'm in a similar situation. I want to put hardwoods down on the ground floor of my home - full concrete slab. I've heard similar opinions on standard engineered flooring vs. solid hardwoods. What are your thoughts on how bamboo would work for this application?

Tom
Re: Hardwood floor over concrete ( not basement)

Guys

No need to discuss the fine points of laminate or engineered floors over concrete. The is a system out that has been around ten years called Elastilon. You can install wood floors from 5/16 to 1 in. You roll out the Elastilon on the concrete floor, put your T & G floorboards down and then carefully peel off the top membrane and the surface contacts the boards and the boards stick to the now exposed sticky surface. The boards are now permanently in place. It is very similar to snow and ice guard for roofs if your have every used that product.

You do have to glue the ends of the boards to each other but that is the only other labor necessary. We are considering it for our new house which will be under construction this year. If the ooncrete is below grade you must use a poly sheet to keep the moisture from coming up or if the floor is more then 3.9% you must use the 6 mil poly barrier. Google it and also find a demo video on you tube.

Sombreuil_mongrel
Re: Hardwood floor over concrete ( not basement)

You are going to have movement issues at the transition from wood framing to slab. The way to prevent movement would be to have a 3/4" plywood underlayment span from framing to slab. So you are going to have to raise the whole thing by 3/4" which is going to mean transitions in height at all other entry points.
The plywood can be attached to the slab (after moisture-proofing) with glue and con-sert (tapcon) screws.
Casey

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