Foundation Has Settled 1/4 inch Need to Relevel Noticed Something Odd - DIY Chatroom

cloves · 10-29-2009, 02:11 AM

Hi everyone I was hoping to get some feedback. I just purchased a house that is partially on a concrete slab. Outer part of slab is cinder block and inner part is the poured concrete. In between the blocks and the center portion of the concrete there seems to be some fiber material/sheets of some sort. I think this is the same stuff that is used when they lay sidewalks. The put this material in between the poured concrete to prevent huge cracks affecting all the blocks.

I have attached a picture that shows the material along with the inner part of the foundation that has settled. You will also notice that there is cutback from the wood flooring that was on top (which we already removed). This cutback does not have asbestos btw (Had it tested).

It been a real difficult process mechanically removing the cutback. I have also tried Krud Cleaner (works also slow) and some remover from homedepot. Same thing slow process and the space is huge.

Does anyone have any recommendations on other products out there that I can just pour on the cutback and concrete that will allow me to level the floor out? I have read about ardex (can't find it at lowes or home depot or the supply houses near me).

Your help/comments would greatly be appreciated

Bud Cline · 10-29-2009, 10:56 PM

Has the slab settled uniformly around the perimeter or has it sunk only in the area you show in the photo?

What are your intentions for new floor covering?

pinwheel45 · 10-29-2009, 11:14 PM

Why not abrade the stuff off rather than trying to remove it chemically? Sand blaster, wire wheel, scarifier, grinding stone on 4 or 7" grinder?

cloves · 10-30-2009, 12:20 AM

Hi all,

Slab dropped pretty uniformly 1/4 inch in the kitchen and living room. Eventually, I want to put on a hardwood floor. My plan of action was to seal the outter perimeter with cement and then use self leveling cement on the inside sunken part. Then once that dries put down plywood and then my hardwood floor on top of that.

I actually did start mechanically removing the cutback with my dewalt polisher (3000 rpm) and a wire bush and a stone grinding disc. However a 4x3 area took me about 5 hours and created a hell of dust storm. Ideally I am trying to see if there is any self leveling cement that can be put down that adheres directly on the cutback saving all the hours of mechanical removal.

PS anyone ever seen that brown fiberous material used inside a slab pour?

Bud Cline · 10-30-2009, 12:27 AM

The brown fibrous material is old fiber board. Fiberboard was used for expansion joint packing many years ago. Leave it there.

Are you confident the slab is no longer moving and changing with the seasons?

If so...you can use a Self Levelling Compound to raise the slab. You better be sitting down when you see what that will cost. In some cases you can add pea gravel to the SLC to stretch it out and lower the cost slightly. You will have to fill the open wounds. I wouldn't use any cement product to do so, I would use pourable caulk. Fill all spots that will let SLC sink into a hole. Then it will be necessary to also use a foam-strip to run around the perimeter of the room to receive SLC. The SLC must be able to expand and contract when it wants to.

All SLC's require their own primer so don't forget that.

Home Depot sells "Level Quick" from Custom Building Products - used tons of it and it is a good product.

cloves · 11-03-2009, 12:01 PM

Hey Bud not 100% sure has stopped moving. The previous owner had carpeting installed over a wood floor. I have been in the house 3 months now. I figured the slab has settled over time (house was built in 64).

Wow I had better be sitting down, ouch! The area of slab is roughly 25x20 or 500sq ft. I went to the depot and they had a bag of SLC and it was 30 bucks but I forgot to take a look at how much that covers. I guess I will also have to look at the primer. Good thing I asked I am new to cement work.

Pourable caulk sounds like the ticket for the perimeter crack! Hmmm don't think I have seen that at any of the big box stores.

Bud Cline · 11-03-2009, 10:14 PM

Typically most all SLC's (50# bag) will cover fifty square feet at 1/8" thick. So...forty bags would raise your floor 1/2" inch for about $1200 bucks.

Can't remember how much rise you need cause I can't see you photo right now.

There may be a cheaper way......

You could check with your local Ready-Mix company and see if they would truck-in grout that could be poured through a window and spread. This type of grout is not to be confused with tile grout. You could even add some pea gravel for bulk if you need to raise the floor 1/2" or more. If my math is correct...about 2 cubic yards would give you 1" of rise. Don't hold me to that right, now my thinking-cap is kinda dim.

cloves · 11-04-2009, 02:36 AM

Holly cow that is a huge amount of money

I am going to take some more measurements and photos tomorrow and post back. Thanks for the quick math Bud much appreciated!

I also read about "mud jacking" but haven't actually called anyone up to see how much that would run cost wise.

itsreallyconc · 11-04-2009, 07:20 AM

self-levelers aren't usually structurally sufficient & are subject to random cracking,,, not an issue IF you're covering w/carpet, etc,,, why not consider polymer-modified conc w/o coarse aggregate,,, it can also be a final finish floor NOT susceptible to floods, pets, OR germs,,, we use elitecrete - cost in the $3.50 sf n-hood,,, just a thought !