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Stretchly · Jan 10, 2011, 08:19 AM

Hi,

I have moved to a house with a separate garage (per-fabricated conctrete walls) and wish to restore it to water tight clean storage/work space.
It looks like the garage was erected over an existing concrete floor that is made up of 3 separate slabs. Unfortunate they meet at different heights causing an uneven floor. What I want to do is repour concrete or screed over the top to make the flor even, and then paint with industrial floor paint.
If I did this the re-pour may be as thin as 1" in parts and up to 3" in others. I wouldn't want to bring the floor up any higher as I'd lose head room and I don't want to dig the fllor out as it would be a real chore.

So, does anyone know if this sounds feasible and if so do you have any advice on the method and materials etc ?

aguywithfeet · Jan 13, 2011, 02:47 PM

This is not my area but, since no one else is has answered ill get a big hub-bub started. I was thinking of doing the same thing at my house. When adding a slab next to an existing slab, the masons at work drill into the side of the existing and insert steel rods with epoxy on the ends about every 2 feet or so. I thought about either removing 4 inch squares of concrete every 3 feet or so in a grid pattern. Then drilling into the side of the existing slaband inserting metal rods. Then I am thinking ill just pour over the top like a normal slab. Hopefully the new concrete will go in the squares and fix to the metal rod strongly enough to keep the top still and what not. I will probably rough up the rest of it with a sledge hammer to try and make it bond better.
Like I said, not my area of construction, but it seems like it could work.
Now let the good ideas come...

smearcase · Jan 13, 2011, 03:41 PM

The only experience I have related to your question is bridge seats on top of bridge caps. The cap is the huge (3 foot square) support on top of the vertical piers of a conventional steel girder bridge. The seats (where the steel girders sit) had to be poured integral with the cap with an exception that seats over 2 inches thick could be reinforced with rebar and poured separately. I realize you are not building a bridge but your thin pour will be squeezed in a similar manner. You may be able to find a special latex type mix that can be used but will be expensive.
You don't mention the condition of the existing 3 slabs with respect to cracking and original thickness. If the existing slabs are cracked, a thin overlay becomes much more of a gamble regardless of material used.
The real big concern for me is the unevenness btween slabs. Expansion and contraction will be erratic (that is the bottom portion of the overlay will be locked against the existing edge while the top portion is free to move which will almost certainly break the overlay at that point. I would definitely create an expansion joint in the overlay at all of the existing joints.
This article may be helpful (I didn't read it completely):Concrete Overlay Materials | eHow.com