Hi -

I'm trying to float a engineered floor over concrete using a cork underlayment and am having serious problems leveling the floor. The instructions on the engineered product that I'm using say that the floor needs to be flat to 1/8" in 8'. I used an 8' steel straight edge and found several places in violation of this 1/8" tolerance. After talking with a local professional installer, he recommended that I use a self-leveling product. Well, I mixed up 400#'s of the self-leveling product (I'm installing over 550 sq. ft) and put it down. While I think that it helped a little bit, I'm still concerned as there are several areas still in violation of the 1/8" tolerance. What should I do? I'm getting pretty frustrated and could use any help.

Thanks,
Alan

Alright, lets start all over alan. The first thing that should have been done is map the floor out marking all the high spots and low spots. I use a 10' black gas line pipe that this part and roll it all around. If you try this do not use a PVC pipe, use a rigid metal.

Deal with the high spots first. Take them down using a chisel, concrete grinder or a concrete scarifier. Getting rid of the high areas will dramatically reduce the areas you think might be low. So you should then map the whole floor again. Fill in the low areas with a trowel-able portland based filler like Mapei Planipatch. This part you can pour and screed and then use a long stainless steel finishing trowel to feather out the edges. After 20 or 30 minutes I take an 8" razor scraper and gently scrape the Planipatch to flatten out any ridges.

Caution here, I don't know what you used to self-level so be careful that whatever you use now can be applied over top what you have now.

Thanks for the reply, Jerry. The self leveling product that I used was Level Quik RS which I found at home depot.

Do you know if I can still grind down the high spots now that the self leveling product has cured? If so, will a concrete grider cause a lot of concrete dust? The floor that I'm trying to install goes through 3 rooms in my house and all have freshly painted walls. I would hate to have to repaint all of that over again.

One last thing, how can you be sure that a high spot is really a high spot. It seems like you would need to measure from every direction and even then, its hard to interpret the result from your measurements. Any tips for measuring the floor?

Thanks for the reply, Jerry. The self leveling product that I used was Level Quik RS which I found at home depot.

Do you know if I can still grind down the high spots now that the self leveling product has cured? If so, will a concrete grider cause a lot of concrete dust? The floor that I'm trying to install goes through 3 rooms in my house and all have freshly painted walls. I would hate to have to repaint all of that over again.

One last thing, how can you be sure that a high spot is really a high spot. It seems like you would need to measure from every direction and even then, its hard to interpret the result from your measurements. Any tips for measuring the floor?

Think flat alan. If your pipe or straight edge teeter-totters over an area that is a high spot. Use a magic marker to outline that and take it down to where the straight edge does not teeter-totter. Now that your straight edge is laying flat look to see if there are any gaps underneath that need to be filled in. If so, mark that area and trowel in a filler.

Forget about level on this whole process, you just want a reasonably flat surface.

You can still grind and it will be dusty, sorry. A scarifier hooked to a good shop vac is not real dusty, but its a much slower process. I think Custom Building Products makes that stuff you used. Contact their tech support people for what to use now, may can use the same product, I have never used it.

OK, thanks for the suggestion. I'm still having a little trouble measuring the floor. For example, if I put my straight edge down on the ground in one direction, it looks like I have a high spot. If I put the straight edge down in a different direction over the same spot it now looks perfectly flat. The more directions I start to look at the more complex it is to understand what is really high and what is really low. Any advice for making it easier to find the high spots?

Do you know if there are any water based grinders that i could use to limit the dust created?

http://www.dustmuzzle.com/pages/dust_muzzle.shtml

check out this link. Sounds like it would take care of the dust problem.