self leveling on slab - Contractor Talk - Professional Construction and Remodeling Forum

maderuyck · 01-21-2005, 05:27 PM

I am installing a bathroom in the lower level of a house on the concrete slab. The slab is approximately 80 years old and is far from being level. I plan on pouring a self leveling floor before tiling but I am having trouble getting info on floor prep. I have heard everything from using a vapor barrier to sand blasting the slab. As it is, the slab is structurally sound, no cracks, chips etc. There is a definite texture to the concrete- it almost looks like tiny rocks in some spots. Another possible variable is that the house is in Minnesota and therefore subject to some temperature extremes.

**Teetorbilt** · 01-21-2005, 09:33 PM

I'd contact a tile setter in your area about the cold. Most of the time we can just vacuum and pour. Sometimes we get a slick pour on a slab and then we acid etch to get some 'tooth'.

Mike Finley · 01-22-2005, 05:59 PM

I think it is going to be determined by the leveller you plan on using. Some require etching, some don't. You need to check the directions the manufacturer says to use based on which product.

**Teetorbilt** · 01-22-2005, 11:33 PM

Mike, The last one that I did was a waterfront condo. My tab was just shy of 300K. The final check cleared just days before Francis and after Jeanne the building was totaled........Whew!

maderuyck · 01-23-2005, 07:47 PM

The two manufacturers that I looked into recommended all sorts of methods to prep the floor but the gist of it was that I needed some "tooth" for the concrete to form a mechanical bond. I think that this old and textured slab already has tooth but I thought there might be some sort of underlayment that will help the bond. I know masons call this new concrete on old concrete a "cold joint" which is frowned upon in alot of cases. Any masons out there?

PipeGuy · 01-23-2005, 08:39 PM

Quote:

Originally Posted by maderuyck

I thought there might be some sort of underlayment that will help the bond.

You can use a 'bonding agent'. http://www.symons.com/products/broch...mical/07ba.htm

Mike Finley · 01-24-2005, 01:15 AM

Like I said it is going to depend on the leveller you use. Maxxon Level-Right doesn't require anything, however there are limitations to every leveller, such as depth you can spread product.

http://www.maxxon.com/choose_self_leveling.asp

Mike Finley · 01-24-2005, 01:20 AM

Quote:

Originally Posted by Teetorbilt

Mike, The last one that I did was a waterfront condo. My tab was just shy of 300K. The final check cleared just days before Francis and after Jeanne the building was totaled........Whew!

300K for what? To level it or put in a bathroom?

Glasshousebltr · 01-24-2005, 07:49 AM

Mad, back in the old days they used to mix pea stone in the concrete to make it go further, Thats more than likely your case, however because columbus descovered the new world they began upgrading concrete after your floor was installed.

Go get you a 60lb elec. hammer for a day, it might cost you 100.00, and take the slab out. You have to install the water closet anyway don't ya? This will make that easier.

Sometimes in construction you have to just jump in, most the time you try to use considerable thought before hand. But your on a jump in project now, so jackhammer away good buddy.:Thumbs:

Bob

**Teetorbilt** · 01-24-2005, 08:32 AM

That was a remodel. Most was spent in the kitch, M Bath and on marble floors.

Mike Finley · 01-24-2005, 10:00 AM

Ah, I see Teetor, I wish you would post some pictures of your projects!

kesac · 02-05-2005, 06:12 PM

Most of those self levelers can easily cure a 1/4" dip. If you have a hump, grind it down. Above that, you can usually put hardeeboard, in a thinset bed, to help level things out, but in 80 yr. old concrete, you might play hell nailing it, or screwing it in.
We used to do mortar beds for tile floors, you might just have to go that route. Some will depend on how much you can stand to raise your floor level.

**Teetorbilt** · 02-06-2005, 02:51 AM

Mike, you know that I'm having problems posting pics, it's really not important enough to spend time on. I'll futz with it from time to time. I have a Yahoo account that I don't know how to work, an Ofoto one that is the same way and I'm terrible about taking pics. I have befores and afters, just not the same job. I just get so caught up in everthing that I forget the camera.
BTW, I am not that enamored by the new digital camera. The batteries have a short lifespan (less than a week in the truck). Overriding all of the auto stuff is a real hassel. The SOB will not take night photos even when mounted on a tripod. There are no provisions for a cable or air release. I'm starting to think that I just bought an expensive vacation camera. With my SRTII or Topcon I can do all of the above easily, go to 1 hr processing, scan photos or negs and get better results.

Mike Finley · 02-07-2005, 11:19 AM

Sounds like you didn't spend enough money on it. If you didn't blow a grand on it I have to hold my nose in the air and can't comment.

Soon I will buy at least a 12 megapixel Nikon or Kodak digital body that accepts my Nikon lenses. Right now I am shooting color negs and having them professional scanned to 18 meg files.

When I was making money as a photographer, my 35mm equipment consisted of all Nikon fm2s - those are fully manual cameras, never owned an autofocus lens back then, nor a body that did anything automatic. Simple was definitly better, a hand held light meter for 35mm studio work or an interpretation of the incamera meter outside was all it took.

**Teetorbilt** · 02-07-2005, 03:21 PM

I thought I had researched it pretty well and it was purchased for job use. It wasn't until I wanted to do some other shots when the shortcomings were noticed. I paid $500 ++++ for it which was a pretty big step up from the Olympus compact that I had been using.
I always liked Nikons myself, I had a few Nikonos years ago, good cameras but sooner or later something leaks. All of my big 35mm's are manual and I wouldn't have it any other way.

pam · 02-27-2005, 04:25 PM

[quote=maderuyck]I am installing a bathroom in the lower level of a house on the concrete slab. The slab is approximately 80 years old and is far from being level. I plan on pouring a self leveling floor before tiling but I am having trouble getting info on floor prep. I have heard everything from using a vapor barrier to sand blasting the slab. As it is, the slab is structurally sound, no cracks, chips etc. There is a definite texture to the concrete- it almost looks like tiny rocks in some spots. Another possible variable is that the house is in Minnesota and therefore subject to some temperature extremes.[/QUOTi CAN LEVEL A FLOOR IN MY SLEEP, THIS IS WHAT YOU DO. GO BY A GALLOON OF LATEX(U CAN GET THIS ANYWHERE) POUR SOME IN A BUCKET, DIP THE SPONGE IN TH BUCKET, SMEAR IN ALL YOU PROBLEM AREAS. MIX REGULAR THIN SET(MORTAR) THINNER THAN NORMAL. PLACE YOUR STRAIGHT EDGE(IF YOU DONT HAVE PROFESSIONAL STRAIGHT EDGES, USE A 2X2 OR WHAT EVER AS LONG AS THE BOARD IS STRAIGHT ON ONE SIDE,YOU WANT THE STRAIGHT EDGE LONGER THAN THE AREA YOU ARE LEVELING , PUT THE STRAIGHT EDGE TO THE HIGHEST LEVEL OF THE CONCRETE IN QUESTION, POUR YOU LOOSE THIS SET ACROSS AND INFRONT OF THE STRAIGHT EDGE AND WITH SLOW HORIZONTAL MOTIONS AND AT THE SAME TIME INCH SLOWLY TO THE LOWEST PART OF THE FLOOR. LET DRY. TILE. IT IS EASIER THAN IT SOUNDS. WHEN IT DRYS YOU SWEEP OFF AREA. YOU CAN ALSO TILE USING MULTIPURPOSE THIS SET. OR JUST USE THE CHEAPER THIS SET AND ADD LATEX. io HAVE DONE THIS A MILLION TIMES IT WORKS. NOT BAD FOR A GIRL HUH

Mike Finley · 02-27-2005, 07:33 PM

Pam, I'm going to have to cry foul on using thinset to level floors. Maybe for something 1/8 or a 1/4 out of level, but anything over that and you are asking for big trouble trying to use thinset much thicker than that - anything over 1/2 inch is suicidal and will void any warranties.

Have you heard of deck mud? It's a simple combination of concrete - sand topping mix specifically, mixed with clean sand. Anything much over 1/4 inch out of level and I would be using that under tile.