i have an existing concrete slab and can i pour a 1 1/2 " slab on top of it or will it crack
2006-08-09 08:12:34 · 5 answers · asked by Anonymous in Home & Garden ➔ Maintenance & Repairs
Problem might be that the foundation for the original slab is not sound and/or the top slab does not stick well. You'd probably have to include some adhesive in your mix if you plan to do that.
We have an old drive that a previous seller placed 1/2" of concrete over to cover cracks and uneveness. We discovered that because after a few years, the top layer of cement is breaking-off in various places leaving us with pot holes and exposed cracks here & there on the drive.
2006-08-09 08:24:21 · answer #1 · answered by Lynda 7 · 0⤊ 0⤋
You'll need to watch the size of the aggregate in the new concrete. And I assume the old slab your pouring over isn't cracked and your putting in expansion joints in the same locations as on the existing slab.
You also need to prepare the old slab by cleaning off any loose material, and either soaking it with water so it doesn't try to pull all the moisture out of your new concrete you pour, or applying an epoxy bonding agent.
2006-08-09 08:22:52 · answer #2 · answered by Jeffrey S 6 · 0⤊ 0⤋
this isn't normal, either the mix contained too much cement or dried too quicky and shrank. The mix should ideally have contained a plasticiser to slow the drying process, or the slab should have been sprayed with water when part-dried. If the concrete is also damp it would indicate that the layer of visqueen (plastic damp-proofing) is missing and the water in the concrete has gone downwards, speeding up the drying process. If the plastic was in place it would have retained all of the moisture, drying out slower As concrete hardens to a peak over a 40 year period this will get worse I would get a structural engineer to look at the damage before passing the report on to the builder. is the house still under warranty? if not you can still claim for shoddy workmanship. The concrete floor is not load-bearing and could be dug up and replaced without affecting any other part of the building
2016-03-27 05:30:04 · answer #3 · answered by Anonymous · 0⤊ 0⤋
I would suggest at least 3" and pouring it at least 6" wider on all exposed sides.
2006-08-09 10:05:02 · answer #4 · answered by jodycat2@verizon.net 2 · 0⤊ 0⤋
it will not crack if it is not to large and you use expansion joint as needed
2006-08-09 08:17:09 · answer #5 · answered by aussie 6 · 0⤊ 0⤋