Second opinion wanted on mastic removal job

djmarcin · 10-12-2012, 02:28 AM

Hi DIYers,

I'm looking for a second opinion on a asbestos removal job I had done in our new house. We had VAT over black mastic (containing asbestos) on top of concrete slab on grade from the 50s. We decided to get it removed to do a glue down engineered hardwood floor.

The contract we have says the abatement company will "Remove and dispose of vinyl floor tile and mastic using 3 dimensional scraping." However, it seems that there is a few mm think layer of mastic left on most of the concrete.

The contractor insists that their scraper can't get up any more and said that if we want more removed we need to pay extra for permits and a "mechanical" removal of some sort. However, a simple putty knife gets up a significant amount of the remaining mastic, so I don't understand the issue with their scraper.

Is this standard or do I have a legitimate gripe here?

More pictures: https://picasaweb.google.com/1051803...sbestosRemoval

joecaption · 10-12-2012, 09:01 AM

A far more important issue is that sure looks like someone layed OSB directly over that slab. A big no no.

JetSwet · 10-12-2012, 09:42 AM

Joe is right & that being said taking the osb up will eliminate this issue. This sounds like the osb was used as a hight filler.

djmarcin · 10-12-2012, 02:40 PM

Hi guys,

Thanks for the feedback. Is OSB = oriented strand board? I'll check and report back but I'm pretty sure the mastic is directly on the concrete and the tan areas are exposed concrete.

If not, any special procedures for pulling up OSB or just start pulling? Or do I have what OSB means wrong?

Thanks,
David

atvrex · 10-12-2012, 05:32 PM

The good news is that a wallpaper scraper or a stand up floor scraper should scrape the cutback (black VAT mastic) right up.
The bad news is it is time consuming.
The VAT is where all (most) of the asbestos was.

"Remove and dispose of vinyl floor tile and mastic using 3 dimensional scraping."

What is 3 dimensional scraping?

Rex

joecaption · 10-12-2012, 05:47 PM

Your correct on what OSB stands for.
I've never once seen tan concrete unless it was stained.
The safest, simplest way to redo this floor is with engineered flooring installed as a floating floor.
I'm just not a big fan of most glued down wood flooring, twice as much when it's below grade.
Far to may people posting with humped up and cupped floors when there glued to a slab.

djmarcin · 10-14-2012, 07:09 PM

I went back and checked -- there really doesn't seem to be anything on top of the concrete unless it is paper thin. Maybe it was stained, or maybe it's residue from the mastic?

You can tell because of where the carpet tack strip was removed.

I'm not really sure what "3 dimensional scraping" is supposed to mean. I think it just means razor scraping.

The top of the slab is actually a few inches above the ground, and all the documents we have refer to it as "slab-on-grade". It also isn't level -- it was built with a grade in the slab from the center to the sides of the house along one axis, about 1/4" per foot. In addition, due to settling it deflects slightly more near the sides of the house. Leveling it out completely isn't really an option because it would raise the floor too much at the walls, but the built-in grade doesn't bother me.

We initially thought about the floating floor but the flooring company we talked to said that in the long run a glue down would be better. They mentioned that a floating floor will stress the T&G system too much and slowly work itself apart over time.

Any thoughts? Reconsider the floating floor? Thanks in advance.

Jim Decker · 10-17-2012, 04:47 PM

Quote:

Originally Posted by djmarcin

I went back and checked -- there really doesn't seem to be anything on top of the concrete unless it is paper thin. Maybe it was stained, or maybe it's residue from the mastic?

You can tell because of where the carpet tack strip was removed.

I'm not really sure what "3 dimensional scraping" is supposed to mean. I think it just means razor scraping.

The top of the slab is actually a few inches above the ground, and all the documents we have refer to it as "slab-on-grade". It also isn't level -- it was built with a grade in the slab from the center to the sides of the house along one axis, about 1/4" per foot. In addition, due to settling it deflects slightly more near the sides of the house. Leveling it out completely isn't really an option because it would raise the floor too much at the walls, but the built-in grade doesn't bother me.

We initially thought about the floating floor but the flooring company we talked to said that in the long run a glue down would be better. They mentioned that a floating floor will stress the T&G system too much and slowly work itself apart over time.

Any thoughts? Reconsider the floating floor? Thanks in advance.

Why not remove the OSB and glue the engineered floor directly to the concrete using Mapei Ultrabond ECO 995?