new garage floor

[liamuk]

I am laying a new garage floor which is 5+m by 3+m I am using a 100mm slab (ready mixed) with a 50mm screed on top. Do I need to think about expansion where the slab meet the walls? Will I need any reenforcement to avoid cracking at a later stage? I will use the walls to align the framework and fill in after. Also I am using a screed because I was told that it is difficult to get a good finish on the slab only.

Liam

[Perry525]

Concrete shrinks on drying.
Cracking is due to a dry substrate leaching the water and cement
out of the mix.
You can proceed in one of two ways. Create a base from compacted hardcore and level with pea shingle then soak with water prior to laying the concrete. Or best, cover hardcore/pea shingle with a DPC creating a tank that will stop the water from leaching out. Do not lay concrete if temperature is above 20 C.
Once it has been leveled and has started to go off, cover with sand and then soak the sand with water every day for ten days.
Make sure the sand does not dry out.

[TheDoctor4]

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