Cinder Block Wall

[borenjay]

I need to build a 3-4 ft. wall around my patio. It is already partially enclosed by a cinder block wall. Does anyone know how I can continue the wall so it completely encloses the patio? Do I need mortar? No I need to fill the blocks? Do I need to dig a foundation? Do I need concrete at the foundation? I am completely clueless and I have no money to pay a contractor. Please let me know. Thanks!

[Richard A Hetzel]

OK, first let's clarify: are the walls REALLY "cinder block", or are they "concrete block"? The term "cinder block" is often used colloquially to describe what's really concrete block. In fact, I'll guess they are concrete blocks, because real cinder blocks would probably have crumbled into nothing by now, being out in the weather.

Yes, you'll need mortar. And you'll probably find that laying block isn't as easy as a good mason make it look. I don't think there is any reason to fill the block cores.

Will you need a foundation? That depends. What are the blocks that are there now built on? Perhaps a concrete slab? For a non-structural wall 3 to 4 feet high, I want to say "probably do need a foundation", but so much depends on what's there and the soils beneath what's there. The blocks have to be built on SOMETHING, either a concrete slab that exists, or a new foundation. If the surface of the patio appears to end at the inside face of the wall, and the wall appears to go past the surface and into the ground, the wall is on a foundation, and yours will have to be also.

What that foundation needs to be depends very much on what region you're in, and what the climate is like, particularly the winter. If you are in a region where frost occurs, the bottom of the footings will need to be 3.5 to 4 feet below the ground surface, which means you may be doing a little digging.

You'll want to cap your wall with a solid block, or stone, or something, perhaps just matching what's there already.