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-   -   Removing basement tile and pouring concrete slab (http://www.diychatroom.com/f19/removing-basement-tile-pouring-concrete-slab-85615/)

tondar 11-02-2010 05:28 PM

Removing basement tile and pouring concrete slab
 
Hey All,

I need to pour a small concrete slab on top of my existing concrete floor in my basement. The problem is that the floor is currently covered with tile. I removed about 12 tiles and found this black tar/adhesive underneath.

My initial plan was to get the floor down to bare concrete and then use Quikcrete concrete adhesive on that section before pouring the slab. Now I'm not sure what to do. I want the new slab to adhere to the existing floor but I imagine it is going to be difficult to get the tar off.

What do you all think? Can I pour the slab right on top of the tar or do I need to get the tar up? best way to do that?

Thanks for the help

stadry 11-02-2010 05:41 PM

CAUTION: that ' black stuff ' MAY be loaded w/asbestos,,, your initial plan's not going to work,,, pls define ' small ' & WHY you need to place a new slab.

if you've got the right answers, just place the new conc on top of the vinyl tiles.

tondar 11-02-2010 06:17 PM

I've been searching on the web and yes the tar probably has Asbestos in it... just like the tiles I took up. I used a mask when taking them up only to read later the mask shouldn't be used for asbestos:(. It was only 12 tiles though and most came up without breaking.

The slab will be about 9 sq.ft. and 5.5" thick. The slab is for a gun safe that I want to bolt down. I didn't want to drill into my basement floor not knowing how thick it is or what's underneath plus the slab will get the safe higher in case of water backup.

stadry 11-02-2010 06:30 PM

that must be 1 bodaciously LARGE gun :laughing: i'd form it & pour right on the floor if that's the case,,, bear in mind you'll only be anchored to an unbonded slab but i doubt if it will float away no matter how deep the water gets :no:

our safe's in the bsmt just sitting on the floor but its only 3'w x 2' deep & 5' tall - unbolted, too,,, if some gorilla wants it that badly, bolts won't stop him :no:

ps - pls post your address & when you'll be out of the house :thumbup:

tondar 11-02-2010 06:44 PM

My safe's about the same size and about 700lbs. Yeah I don't think anyone is going to be picking it up and walking up the stairs with it. However, most safes are easier to break into when they are on their sides so anything I can do to keep someone from being able to push it over I want to do.

If I pour directly on the tar then it won't bond to the existing floor?
If I want to have the slab bonded how would you recommend I get the floor to bare concrete?

Quote:

ps - pls post your address & when you'll be out of the house :thumbup:
I'll get right on that :)

stadry 11-02-2010 06:57 PM

elec grinder, diamond cup wheel, dust shroud, & hepa vac + organic respiratory mask,,, you can rent the grinder w/shroud & vac at the apron store of your choice - even the diamond grinding wheel.

bob22 11-03-2010 10:01 AM

Why not throw some masonry bolts into the existing slab for the new slab to anchor onto?

tondar 11-03-2010 05:27 PM

Mainly for the same reaon I didn't want to bolt the safe to the existing floor. I really didn't want to drill into my basement floor. I don't know how thick it is or what's underneath (sewer pipe is near by desired location). I'm probably being paranoid but I'd rather be safe than sorry.

federer 11-04-2010 01:13 AM

post some pics when you are done!

tondar 11-04-2010 12:55 PM

update...

Although I will take itsreallyconc's advise I am first trying to remove as much of the mastic as possible. I read on the net good reviews for this stuff called Bean-e-doo. Luckily there was a place not too far from me where I could get some. It's non-toxic and is designed specifically for removing this stuff. So after I remove as much as I can I will then grind what's left to expose clean concrete for the new slab to bond too (following my original plan of using the Quikrete concrete bond).

One other question having never poured concrete before. If I use the crack resistant quikrete should I put down any kind of wire mesh?

Thanx

Bondo 11-04-2010 07:30 PM

Quote:

So after I remove as much as I can I will then grind what's left to expose clean concrete for the new slab to bond too
Ayuh,... That would really put all that asbestos into your air,... trapped in the mastic, it's harmless...

I think I'd drill abunch of 3/16" holes in the area, an Inch deep...
Then bottom out some 3 or 4" 1/4" tapcons....
You could string wire or whatever between 'em....

No way in 'ell it's goin' anywhere, 'n the asbestos is still locked in captivity....:thumbsup:

tondar 11-04-2010 08:28 PM

Quote:

Originally Posted by Bondo (Post 528707)
Ayuh,... That would really put all that asbestos into your air,... trapped in the mastic, it's harmless...

I think I'd drill abunch of 3/16" holes in the area, an Inch deep...
Then bottom out some 3 or 4" 1/4" tapcons....
You could string wire or whatever between 'em....

No way in 'ell it's goin' anywhere, 'n the asbestos is still locked in captivity....:thumbsup:


I don't agree... The asbestos is in the mastic. Bean-e-doo doesn't separate the mastic from the asbestos it basically liquifies the mastic so you can get rid of it. Removing the amount of mastic removes proportionally the same amount of asbestos. Thus when you start grinding there is less asbestos there to begin with.

I just finished with the Bean-e-doo. It works very well, pour it on and wait a couple hours and when you come back it looks like motor oil on the floor that you can clean up. I ended up doing it twice though to get rid of almost all of it.

I do like your other idea though... maybe I'll do both... but what's a tapcon?

bob22 11-05-2010 12:28 PM

"Why not throw some masonry bolts into the existing slab for the new slab to anchor onto"
"Mainly for the same reaon I didn't want to bolt the safe to the existing floor. I really didn't want to drill into my basement floor. I don't know how thick it is or what's underneath (sewer pipe is near by desired location). I'm probably being paranoid but I'd rather be safe than sorry. "

"I do like your other idea though... maybe I'll do both... but what's a tapcon?"
A screw that can be screwed into holes drilled into concrete.


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