Cinder block fire pit questions


Old 05-01-18, 04:24 PM
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Cinder block fire pit questions

I'm thinking about building a fire pit in the backyard, on the cheap, using 8"x8"x16" cinder blocks. The design would be 48"x48" square, dry stacked two high, with a 4" cap. The inside would be lined with either a steel plate or fire brick.

If I filled the blocks with concrete, how many 80# bags would I need? Or would it be easier/better to fill the blocks with gravel?

I don't want to get too much money into this project, but don't want to cut corners and end up redoing it in a couple of years either.

Any thoughts or suggestions would be appreciated!
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Old 05-02-18, 03:04 AM
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Block will disintegrate from the fire's heat. You'd need to have an air space between the block and the steel or firebrick.
Old 05-02-18, 04:16 AM
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Mark is right . . . . we have a burn pit made of loose cinder blocks (maybe 40 of them) that gets moved around from place to place every few years; and every time we re-build it, about ⅓ of them have fallen apart. Frost may have something to do with it too.

We don't mind much; ours is just to burn trash and garden debris, and the blocks provide a bit of a windbreak from the prevailing winds . . . . and the size of the pit can vary from year to year depending upon how large the amount of debris is that we have to dispose of.
Old 05-02-18, 04:40 AM
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If you do a search for "concrete to fill block" you will find several calculators that help you estimate the amount of concrete needed to fill CMU block. Keep in mind that there are different types of block so it's only a rough estimate.
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