CJ, I am assuming you have concrete and not cinder blocks? correct? concrete usually holds up to heat fairly well. It takes enormous temps to crumble it. cinder blocks really are made with cinders and are a glazed purple-y color. We had our basement laid up with them in the house I grew up in. very dark down there. and I think they weren't as hardy as concrete blocks ( they are lighter in weight and thinner walled) but it could have been the age of the house. It was built in the late 1800's . It came from Sears and Roebuck off the train. it came as a kit and was built from scratch.
They are not as good as the solid ones but do work and I know folks that have built a BBQ pit out of them. Just dont build a roaring fire in them and they will last ya for a few years. Dont build your fire right against them they will last longer. Filling them with sand as you stack them helps too.
Ok. And sorry Carolyn for the short response earlier. Morning was hectic here with everything going on. I have a bunch of both types from that find I spoke of earlier. And a friend of my guy's has a pallet full left over from a side job. He's going to give them to us when Brent goes back to ND next week. Ya might have noticed the curved edgers I have for a small pit in my back yard (in the pictures I've posted). Little fires. But we can't cook on them. So. Yeah lots of projects next time he comes back. Thanks cappy. There's a bunch of mortar and old bags of concrete I need to pick up from Lowe's. My friend works there and out a bunch asside for me that had tears in them. Maybe fill the holes with what we have left over from making the outdoor kitchen.
