Tried building a DIY fire pit with retaining wall blocks, thing cracked after 3 fires

I spent about $150 on those interlocking concrete blocks from Lowe's in June, stacked them up in a simple circle in my backyard in Austin. After maybe 3 small fires for s'mores, I noticed a big crack running through one of the blocks. Turns out regular blocks aren't rated for high heat, they trap moisture and explode when heated up. Anyone else run into this with cheap blocks, or is there a specific brand that holds up better?

2 comments

2 Comments

king.aaron9d ago

Honestly, I learned that lesson the hard way too. What worked for me was picking up some fire-rated blocks from a landscape supply place instead of the big box store. They cost a bit more but haven't cracked once after a whole summer of fires.

victorbutler9d ago

Found out the hard way too, man. @king.aaron is spot on about landscape supply places having the right stuff. Did you just use regular mortar or did you dry stack those fire rated blocks? I ended up grabbing some from a local yard, but I'm wondering if the type of mortar matters just as much as the block itself.