I want to set ninty 8x8x16 cement blocks as columns for support to a room addition. How do I estimate the amount of mortar I will need?
You will need about three bags of 94# portland 1/2 cu yard of sand. The mix is 1 part cement to three parts sand (all % are by volume) Basically, the cement fit into two 5 gal pails. The sand should be three time that or 6 buckets. Add emough water to make a plastic consistency. If you don't set the block quickly mix 1/2 batches or the cement will get hard and be useless. Good point is too fill the block solid as you go.