Help identify this subfloor, and then how to address it

[jfred]

We are remodeling our living room and fireplace and tearing out the old carpeting and fireplace hearth. We will be installing engineered wood flooring throughout the living area and terra cotta tiles for the hearth. I removed a section of the carpet to get an idea what type of floor prep I have a head of me... and found this. I am working on an above grade concrete slab, and found this black/brown cardboard like material between the carpet padding and the concrete slab. It seems like it is going to be very tedious to remove all of this... so my questions are:
1. What is this material?
2. Can I install engineered wood flooring and terra cotta tiles over... or does it need removed. If it can stay, any preparation recommendations?
3. If it needs to be removed.. any tips for this process?

Any advice or input is greatly appreciated. Thanks in advance for your help.

 

[DarisMulkin]

It looks to me to be Celotex sheathing. As for th rest of your questions I don't know.

Daris

 

[FloorMaven]

I assume you mean on-grade concrete slab? You can't glue to it but if its flat enough you can certainly float.

 

[jfred]

FloorMaven - our first floor is an elevated concrete slab over the basement level. Do you think I can possibly float the engineered wood over that subfloor... but I would need to remove it for the terra cotta? Thanks for your help!

 

[eric248]

Looks like masonite

 

[Floorist]

Looks like masonite

That's what I think, too.

 

[Ken]

I know EXACTLY what that is. AAAAH run! Just kidding. Its a paper/mdf composite board very popular only in certain geographic areas. Get rid of it! Mallet and a prybar if you dont want to buy a bigger scraper. I also have one of those 6' iron post hole diggers that fence guys use to cut through roots, that would make quick work of it. My preference is always get it down to the subfloor if possible. Good news is it should come up pretty easy. Bad news is its going to be HUGE mess, lol. Good luck!

 

[jfred]

Ken - that sounds about right, it seems soft enough to be some sort of paper composite. So just scraping and elbow grease? I didn't know if they made something I could spray onto it in order to 'loosen' it up before scraping?

Eric - I received your message, it's about 1/8" to 3/16" thick.

 

[FloorMaven]

I believe Daris is correct, it's an insulated sheathing. Probably from Celotex. I ran into this just last week on a project where I'll be installing engineered wood.

If floating is a viable option I don't see why it should come up as long as its in good condition.

It will have to be cut out and replaced with cement board for the hearth. I have to say its unusual to have a residential above grade slab. I've only encountered this a handful of times and those homes have been customs built into mountainsides.

 

[FloorMaven]

It's cellulose fiber.

 

[eric248]

I never seen , sold or heard of a 1/4 Celetex . 1/2" yes and can still be bought

 

[FloorMaven]

If its old it could be asbestos laden.

 

[FloorMaven]

http://inspectapedia.com/structure/Fiberboard_Sheathing.htm

 

[DarisMulkin]

If its old it could be asbestos laden.

No asbestos according to the site you posted FloorMaven. I've seen lots of it but it was on the outside of the house. They used plywood on the corners when framing and the Celotex on the rest of the structure. Not the roof though.

Daris

 

[Floorist]

Our house had it on the walls in one room when we bought it. They used it to cover bad plaster. Never seen it on floors.

 

[FloorMaven]

No asbestos according to the site you posted FloorMaven. I've seen lots of it but it was on the outside of the house. They used plywood on the corners when framing and the Celotex on the rest of the structure. Not the roof though.

Daris

I read that too but I also read it contains asphalt and it could be adhered with an asphaltic adhesive. Both could contain asbestos.

So why open that can of worms if you don't have to?

 

[FloorMaven]

I had a house on LI built in the 50s that was sheathed with it. When I had vinyl siding installed I was trying to make the point to the installers that they need to nail into, not between studs or a strong wind will blow the siding to the next town. Homosote is more popular for floors but who know who did what when.

 

[Ken]

I wouldnt spray anything, thatll just make a mess. Just go to town.

 

[Nick]

That has to be the crap i have as insulation on my house built in the 50s .

Will be gone this summer when i install new vinyl siding .

 

[FloorMaven]

That has to be the crap i have as insulation on my house built in the 50s .

Will be gone this summer when i install new vinyl siding .

Celotex has been one of the larger asbestos defendants so anyone that is thinking about removing the stuff should pay attention to asbestos abatement guidelines.

http://www.jdsupra.com/legalnews/author-michigan-state-university-v-asb-86077/