Pouring concrete over existing concrete

Question

Basically I have two adjoining rooms (Room 1 and Room 2).  The concrete slab in Room 1 sits about 3″ lower than Room 2.  Also, the lower portion of Room 1 extends about 2.5′ into Room 2 and there are french doors separating the rooms.  Previously there was a wooden riser that extended the 2.5′ from the doors to the raised slab in Room 2 and the whole thing was carpeted.  We plan on tiling and the plywood that was there flexed too much for the type of tile we are using.

Now in order to tile, we need to raise the area from the doors to the 3″ step in room 2 and I thought I would just pour new concrete.  The new concrete slab would be 2.5′ by 6′ by 3″.

Is it advisable to pour new concrete over an existing slab?  Does it make a difference that it is such a small area? If pouring concrete is the best way to approach the project, are there any special techniques that should be used?

 

Thanks in advance!

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mdekiss 1 year 1 Answer 373 views

Answer ( 1 )

  1. Honestly, you’re only going 3″ thick and it’s on the inside. You could drill and pin the existing to the new but you really shouldn’t have to. But without seeing it, I would just build it up with wood.

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