Hi All,

I'm just about to start a major renovation on my apartment, and I'm a bit concerned with how the GC has decided to tackle the floor.

My apartment is on the 37th floor of a building with slab concrete floors. Right now there are 3/4" solid wood parquet tiles glued down with something that looks like tar. There are no loose tiles.

The GC wants to trowel self-leveling cement over the parquet, install a vapor barrier over that, and then nail the wood (probably engineered) into the whole mess. Should I be concerned with this method?

I've been thinking that it will probably be safer to pull up the parquet, level the concrete slab, and then float engineered wood. How do I deal with the black glue? Can self-leveling cement be poured directly on to it?

Thanks so much! This whole process has been terrifying, and I'll never get through it without great advice from the experts. Thanks again!!

It is probably NOT true 3000 lb. concrete. More than likely, it is Gypecrete. A lightweight cementious underlayment poured over either steel or wood subfloors for sound and fire proofing.


Yes. I would not recommend nailing into a cement based self leveler. It will crack and crumble and eventually make noise. If the existing floors are well adhered, simply sand down any high spots and flatten to industry specs then nail/staple the flooring to that, after installing the proper felt/building paper. In otherwords, skip the leveling compound.



Not sure why the existing floor needs to be removed unless after installing the new floor over it, the floor will be too high.

The safest method would be to flatten the existing floor as well as possible by sanding high spots, then float a floor over that, using the proper foam underlayment. You won't be having moisture problems from below the floor when you're on the 37th story of your building.

Hi Gary,

Thanks for the quick response!



I don't know if it makes any difference to your answer, but the super told me that the floor is 8" concrete slab.

I really like your idea of just sanding the parquet as the other method just sounded WRONG.

In your opinion, do I gain anything by nailing the floor down to the parquet or is it just better and safer to float it? My previous apartment had terrible Pergo floors that sounded incredibly hollow. Assuming I use a proper underlayment, will I avoid the hollow sound?

Thanks again!!!

Not to mention, the moisture from the self leveler, buckling the existing wood, especially placing a moisture barrier over existing wood.

Yes, even concrete way up on upper floors, still have vapor emissions, believe it or not.

I'd go with taking up the existing. I don't think you are supposed to sandwich hardwood when its installed over concrete.

Exactly correct.

I'd agree if this was on the ground floor. Furthermore, I'm having a hard time with a solid 8" thick concrete slab on the 37th story of a modern building. How old is this building and how high? That's how they USED to make them if the were 5 stories and built in Mexico. Tall buildings are built with steel framework and decks, only using re-enforced concrete in certain structural locations. But anyway, one can install hardwood over hardwood. I would NOT use an impermeable barrier between them, like plastic. But instead a permeable one, such as 15 lb. asphalt felt. If one started to remove the parquet and it began taking up the gypecrete underlayment, that would be a problem.

The building has 40 stories and was built in 1968, and I'm certainly not in Mexico. Maybe the super is wrong about the floors.

I really like Gary's advice because he sounds like he knows his stuff, and it doesn't require pulling up the old parquet! The new plan is to sand down the high points of the parquet, install floating engineered wood, and hope for the best.

Is there an underlayment that comes highly recommended?

Thanks again!!!

Make sure the underlayment, what ever you choose, does not have the moisture barrier. Even neopreme underlayments can trap moisture, to an extent.

Although I have not used it, this, I've heard, comes recommended for FLOATING floors. If nailing/stapling down, use red rosin paper. It is always wise to check for moisture, although I'd be surprised to see it be excessive at 37 stories above ground.

http://www.flooringunderlayments.com/floormuffler.html

This one as well.

http://www.acousticalsurfaces.com/echo_ ... r.htm?d=16

if your parquet is securley fastened and is a 3/4 you can nail right into that. You may have to use a 3/8" eng due to height restraints but thats what I would do. I would acually put a 3/4" solid down if it didnt cause any transition problems.

How thick is this parquet, that is installed(as a gluedown) over concrete. Are you absolutely positive it is 3/4" and not the normal 5/16" tiles??

This is what the poster stated at the git go and is all we have to go on. If the info is correct ( could be, maybe not ), then stapling down to the 3/4" should be fine, IF it's flat and secure. Floating is always safer.

Read the manufacturers specifications on this. It is not a good ideal to install a floor over a glued down wood floor, over concrete.

Thanks for all the info, guys! Sorry for not responding, but we took a few days off the reno to go camping.

I just measured again, and the parquet is exactly 3/4". I tried to check the levelness (?) of the floor and it seems as though it's mostly even with some high spots. If those can be sanded down flush should we reconsider nailing hardwood into the parquet?

Also, we're planning on bringing the wood into the kitchen (tiny NYC kitchen), but what goes underneath the cabinets and appliances if we decide to go with floating?

Thanks so much again! You guys are invaluable! If anyone needs any advice on perfume (I'm a perfumer) I'd be more than happy to help!