Hi, As you will see I am a complete newbie here. Currently I have a concrete patio laid in 2 parts, which I would like to lay a patio on. (I know its not Ideal but there money and time considerations). The first problem is that whoever laid the second piece of concrete messed up the levels.
By my calculations in order to make good the levels the bedding in some regions would need to be as deep as 90mm. This brought me to my next concern of the added weight, as part of the basement of the house portrudes out and under the patio.
The concrete base is pretty thick and to my eye seems very stable but am I taking one chance too many?
I wouldn't worry too much about the weight: laying 100-150mm of paving over the slab is only adding 200-300kg/m² which isn't all that much in the scheme of things.
As for the build-up, again, as long as you use a sand/cement mix, I'd be happy with the 90mm depth in localised spots. In fact, the correct method would be to fill the hollows first, bring them up to the slab level using summat like a 4:1 mix, and then lay the paving on a uniform 25-40mm of 4:1 mix. You can count on the fingers of one elbow just how many contractors would actually do this as two separate operations!
Can I just clear up the mixes. I was going to use a 10:1 bedding mix and was thinking about a Lean Mix for the deep areas, but are you saying it is best to go for a 4:1 mix all over only do the dips as it were in two parts?
