Sand and Mortar Quantities

Dear Tim: I would like to know how many cinder blocks will one bag of mortar mix lay? I want to figure out how many bags of mortar mix I will need to set 1500 cinder blocks.

Dear Barry: That is a pretty interesting question. The standard I used for many years was the following: 2.5 bags of pure mortar mix and 600 pounds of sand per each 100 blocks you intend to lay. I am assuming you are laying a standard 8 x 8 x 16 inch concrete block.

The quantities change significantly for brick since the average brick is so much smaller than a concrete block. You need many more brick than block in a given wall. This means more bed joints and more vertical head joints. For brick you need: 7 bags of pure mortar mix and 3,000 pounds of sand per thousand brick.

It is vitally important that you buy all of the sand and all of the bags of mortar at the same time. If you mix batches of sand and mortar there is a good chance you will end up with different color mortar once dry.