How do you work out how much sand and cement will be needed for an extension?

Question:

Answers:
length *width* height. Just figure out the volume of the area. Depending on local codes you would need a ceratin amount of sand and concrete to certain depths. If the slab will be structural or if it is just for like a shed. Look at the local building codes to see what you need. Figure out the volume and them call a company to bring that amount in for you