Concrete floor

[djoakes]

Hi, Iam converting an old barn, we need to lay a concrete floor 6 metres wide x 22 metres long, will 4" thick be OK we have laid a 6" hardcore base, can we lay this in one large slab with expansion joints around the edges? or will I have to do it in seperate bays? we will be laying a stone floor on top of the slab.

Thanks David

[Tony McC]

You really need to consult a structural or civil engineer on site. However, as a very rough rule of thumb, no concrete bay should be more than 6 metres in length/width without including some sort of crack control or movement joints. At only 100mm thickness, I'd go for 4m max bay size, if poss.