How to Make a Concrete Parapet

Measure the distance between the holes in your cinder blocks. Drill a row of 1-inch diameter holes spaced that far apart in the surface upon which you'll be building your parapet. Exactly how deep you'll be able to drill will depend on the structure of the foundation you're building on, but aim for a depth of between 1 and 3 feet.

Insert a 1-inch steel pipe into each hole, long enough that it extends above the parapet almost to the desired height of your parapet.

Mix Portland cement and water until it reaches a paint-like consistency. Spread this cement paste on bottom edge and short sides of a cinder block and slide it down over two of the pipes. Do the same with other blocks until you have a complete row.

Add another row of blocks, again using cement paste as mortar, but this time offset by half a brick to increase the parapet's cohesion. The visual effect should be similar to that of a brick wall. Cut blocks in half to place at the ends of the parapet, if necessary. Continue stacking staggered rows until you reach your desired height.

Mix 3 parts gravel, 2 parts sand and 1 part cement, adding water until you reach a thick but workable concrete consistency. Pour the concrete down through the holes in the top of the parapet, filling in the gaps in the cinder blocks and the center of each steel pipe. Wait 24 hours for the concrete to harden.

Spread cement paste over the upper surface of the parapet and top it with a row of concrete slabs to finish.