Introduction: 40 Inch (Inner) Diameter Retaining Wall Fire Pit ~ $110

As stated in the title this fire pit cost me about $110 for the raw materials. The inner diameter is 40 in (102 cm) while the outer is 54 in (137 cm). I purchased materials from both Home Depot and Lowes and I recommend visiting both because they had different block colors and sizing if you want to create a variation of this pit.

Raw Materials: 6 bags of .5 cu ft of drainage gravel (Lowes)
                           42 Retaining Wall Blocks (Home Depot)
Tools Needed:
                            Rubber Mallet
                            Level
                            Shovel
                            Angle Grinder with concrete-ready blade (only needed if you get blocks that do not have two level faces)

Step 1: Place 14 Blocks in Circle

You could use a string and two pencils to mark out a more perfect circle, but I found it easiest to just lay the blocks in the best circle I could. Then, use a shovel or a stick to mark the outer and inner edges of the blocks.

I would also like to note at this point that you could use any number of blocks for different size fire pits and 12 would actually be the easiest to set up because the angles work the best. I chose 14 simply because I liked that size.

Step 2: Remove Blocks, Dig, and Lay Gravel

Dig out in between the two circles you marked to a depth of  2- 3 inches. Fill this with gravel. It will help when you need to level the blocks and it also helps with drainage.

Dig a hole in the center of the pit about 20 in deep and 15 inches in diameter. Fill this with gravel for drainage.

Note: My pit was located in an area with wood chips so the area already drained well, hence less drainage rocks were needed. If you have clay soil I would advise following the instructions from this old house on the trench/ hole depths. Or you can use your own discretion.

Step 3: Remove "Tags" With Angle Grinder

This step is only necessary if you decide to use retaining wall blocks that have little maybe 3/4 inch ledges on one of faces which I call tags for some reason.

Yes it makes life easier if you use blocks that do not have these "tags", but in order to have this color at from my local Home Depot it was my only option.

So to get rid of the tags I cut across with the angle grinder then "scraped" any remaining part that prohibited the face from being perfectly level.

Step 4: Lay Blocks on Gravel Ring

Move the blocks back onto the gravel ring and tap them down with the rubber mallet. Use the level and the rubber mallet to make sure all blocks are level. Then you simply add the next two layers of blocks with the centers in line with the gaps from the previous levels.

Step 5: Add Remaining Gravel

I dumped whatever gravel I had leftover into the pit to get a full coverage of about 2 inch depth. Again use your judgement on your particular soil type to whether you need a deeper layer or gravel or if you would like to dig the pit down a couple inches before adding gravel.

The one thing I was worried about was cracking of the blocks. I have had 3 fires in the pit so far without any cracking. I will post an update if the blocks do ever crack. Overall for a little more work I saved at least $300 because a similar sized kit would have cost me at least $400. The kits do have a steel ring which helps form a perfect circle,  but I was told by a local stone retailer that it was not necessary in order to protect the blocks from the fire.

Comments

author
TammyK44 (author)2017-07-06

Do you have any updates on the bricks? I am about to buy some and want to know how they are doing.

author
KathyK72 (author)2016-07-17

These have been the most understandable instructions I have found yet, and actually had the materials list, thank you! I was going to ask though, I do not need to use adhesive of any type between the layers?

author
valcider (author)2016-06-25

Unfortunately,I've had some health problems lately and haven't been able to do too much,but I'm planning on getting back into the swing of things very shortly.

author
valcider (author)2013-09-03

Very nicely done.I'm looking to build something similar in my own backyard.This gives me a good start.Thank you!

author
KootenayS (author)valcider2016-04-13

How's the fire pit holding up?. I like your idea and want to make one if it's working good!

author
AverageGuy (author)KootenayS2016-06-25

I have had mine for three years now and it is still holding up well. It has not been used as consistently as I had hoped but it still has had a number of uses. The one thing that has happened is the inside of the blocks have turned a reddish color from the heat. I may post a picture of the result.

author
valcider (author)KootenayS2016-04-14

unfortunately,there's a "burn-ban" in our area and i wasn't able to use it yet,but when I do,I'll let you know!

author
livy.morgan (author)2014-11-17

Have u had any blocks crack?

author
AverageGuy (author)livy.morgan2014-12-08

Nope, all the blocks have been okay so far.

author
jcastaneda5 (author)2014-09-23

Should i use type S mortar to make the joints better and a little more secure. it will also add some height to the blocks so that way i could maybe save some more money by not having to buy more block. i work at Lowe's so i can already get some stuff cheap, but i swear... i must have had a Jewish ancestor somewhere along my family tree because i am just such a penny pincher. i already asked they guy in commercial and he said he would have to look it up so i sent him the link to this ible, we'll see tomorrow.

author
AverageGuy (author)jcastaneda52014-09-29

As long as you do not build the pit too high then the weight of the blocks alone should be be fairly secure. This is especially true if you build a pit smaller than mine so that the blocks align in their natural angles. It could help tie things together though as you said. And it would probably look nicer since you could fill in the gaps. Just be prepared for a good deal more work. I myself would not recommend putting mortar in between the layers of blocks (to increase height) as it would be a ton of extra work and I personally think it would not look as nice. If you are that concerned about stability you can use construction adhesive to glue the blocks to those below them.

Hope this helped

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