Pouring concrete over concrete

I have an old hog house that I'm thinking of taking the existing structure down and putting up a new building on the foundation to make a shop.

I has a concrete floor that is OK, but it would be nice to have something smoother. The existing floor is about 6" thick. Is there a way of pouring a thin coat of crete (maybe 2" over the top) to smoothing things out? Or, would something that thin just crack?

Don't know what area of the country you are located in, but look up someone like White Cap Supply or some other concrete supplier and see what they would have in self leveling toppings that can be poured over existing floors. I have seen some nice looking floors come out with it and minimal or no cracking either.

It can be done with the right product and proceedure.

I have nothing to add about the concrete. I would advise using at the least one or two studs from the original building in the new building to avoid changes in the building codes. you are repairing a building if one stud is still standing otherwise you are building a new building and the codes can be different to the point that they will not let you build on that site or foundation.

If change in use or codes is a concern, then he needs to check into what constitutes a new building. Some areas require an entire wall to be left standing. I know one guy who knocked down three walls of his cabin, rebuilt, and then did the fourth a few years later.

Google Ardex.Go to the website.

I've poured many 2" overlay slabs. Normal concrete can be used, though it should be saw cut into a grid to control where the cracks occur.
All concrete cracks, the control joints just keep them straight.

2" is often used, Our concrete nowdays has alot of larger stone in it---this makes it a real pain at best. They have figured out that they can make the same test with less cost.

Therefore we most times use a sand mix, there isn't so much strength, the cost is more, but sure alot less troubles.

They have changed their minds as years ago rock was only a filler, but now it is (strength)

My son is project manager for a company that specializes in a product called Maxxon or Gypcrete that is a sand based concrete designed to pour ontop of old concrete. they usually pour it 2 inches thick unless in-floor heating is installed! It adheres to the old concrete and is stonger then regular concrete and is self-leveling with no striking or troweling and can be walked on in just over 2hrs! Its mixed in a machine outside the building and pumped into the building thru 1 1/2 in hose, quite the stuff!

Son-in-law woked for a concrete form company - told of an epoxy that they covered existing concrete and adhere to new layer. I would certainly look into it. Have seen many attempts to cover existing with new layer, succumb to the elements, cracking and breaking up because new doesn"t adhere to lod.

Son-in-law woked for a concrete form company - told of an epoxy that they covered existing concrete and adhere to new layer. I would certainly look into it. Have seen many attempts to cover existing with new layer, succumb to the elements, cracking and breaking up because new doesn"t adhere to lod.

I think there are 3 ways to look at this, place a new slab over the existing, thick enough say 4" so no trouble with reinforcing, fracturing and whether you want to bond the new slab to the old, hard to say how it could react, as things expand/contract. Epoxy can be used to bond new to old. Concrete has capillaries and will absorb moisture, water etc. when it freezes then thaws, things happen, so a thin layer is subject to freeze thaw, you don't want moisture in between the layers if in a cold climate, it will spall and come apart eventually.

Demo it, regrade, place good sub-base material, compact, well drained, place a new slab with 6" woven wire mesh or similar.

Thin coating products like Maxxon, mentioned below, are typically used to level out floors/decks of buildings or has been my experience with it, like for a precast concrete plank type building where you have camber in each piece of precast, center is higher than the ends. Typically, they will use a 3000 psi flowable grout to level those, but some owners want that extra layer, depending on the finish schedule, and flooring materials specified. I did an entire precast concrete plank building with this material, after it was grouted, roughly 80,000 sq. ft. worth.

I am not convinced, (and I may be wrong LOL !) that a material like this is suitable for a wear course, it is self leveling, and with correct surface prep of the existing slab, it should achieve a decent bond, but I don't recall what the actual strength is, results will vary.

The compressive strength is also something to consider, it needs to be similar or the same as what is under it, or it could fail under a heavy point load, like a wheel. Bond and compressive strength are 2 important aspects, but also abrasion resistance and the surface finish, this material is smooth once set. One would think in today's modern world there would be a material that can work as a wear course over existing concrete, some research might be in order on concrete repair materials.

Another thing to remember, if it is a quality material it will be portland cement based, Gypcrete may be gypsum based and from my years doing high rise, institutional, and many other kinds of commercial buildings, gypsum based materials often times cannot perform like a portland cement based material, because it does not have the compressive strength of portland cement. An example of this is spray applied fire proofing that is applied to structural steel to achieve an hourly fire rating, the gypsum based material has to be re-done often times during the construction phase as it does not hold up as well as the portland based does with construction activities going on that tend to disturb the material after it is applied.