This article was originally posted in Instructables and is reposted with permission from Dewey Lindstrom.
We recently moved from the remote North Woods of Wisconsin where large lakeside fire pits were simply dug into the ground and lined with large rocks, creating great campfires. We now live in a residential neighborhood in the Central Valley of California. Campfires here are confined to well-defined containment systems and small controlled fires. These can be easily extinguished with no sparks or embers and can continue to burn or blow into neighboring combustibles when left unattended.
Even with these restrictions, our family still loves to sit around an evening fire. But we didn’t want to spend a small fortune on a pre-manufactured fire pit or a contractor-built unit. We were also not sure where we might want the pit permanently located. So, we needed something we could take down and move to a different spot without a lot of trouble or expense.
Fortunately, while cruising the aisles of Home Depot recently, we saw concrete tree rings on sale for $2 a section. We borrowed a tape measure and quickly determined the rings might make a dandy low-cost fire pit that would incorporate a small Weber grill (which we already owned) as an inner firepot, allowing a very controlled burn and positive air shut-off to extinguish the fire when we were ready to call it a night.
Weber Smokey Joe Portable charcoal grill or equivalent 14-inch diameter grill. ($30 new)
4 sections of 14-inch inside diameter concrete tree ring ($2 to $3 each = $8 to $12 total)
6 sections of 24-inch inside diameter concrete tree ring ($2 to $3 each = $12 to $18 total)
2 cubic feet of small stones, pebbles, road gravel or decorative rock ($0 to $20 depending on how fancy)
Total cost: $50 to $80 depending on your taste in stones.
Find a nice level area of your yard or create a level circle approximately 3 feet in diameter. It's not absolutely necessary, but we sprayed our pit area with weed/grass killer to make a bare spot. You will notice the ring of browned grass surrounding the pit in the final photos.This is due to the weed killer and not the result of heat from the fire.
We also placed a layer of weed barrier cloth under the pit to prevent grass or weed from growing up into the pit.The tree rings will be more stable on bare earth than on grass, particularly if you have Bermuda grass like we do. Also, you should have no problem if you want to place your pit on top of a concrete or brick patio.
The trick to turning tree rings into a decent looking fire pit is to make the ring two sections tall by turning the fluted top sections upside down so they interlock with the fluted bottom sections. The first photo shows what the 14-inch tree ring sections look like when you buy them from the store and the second photo shows them stacked. They don’t fit perfectly, but the small air gaps look sort of decorative in my estimation and are barely noticeable once the unit is being used.
We thought the 14-inch tree rings looked a little puny by themselves so to give the fire pit more mass, we surrounded the inner ring of 14-inch tree ring sections with an outer ring of 24-inch diameter sections. The sections are 2 inches thick, so the outer diameter of the completed fire pit will be 28 inches.
Note that the 24-inch outer rings have a very convenient tab locking design. One end of each section has a tab and the other end has a slot. This helps a great deal to stabilize the rings when they are stacked two high.
You will quickly notice that when the 14-inch rings are stacked inside the 24-inch rings that there is a 3-inch gap between the inner and outer rings. You will also notice that each 14-inch ring is about an inch shorter than each 24-inch ring.
To solve both of these problems, the outer ring is erected first and then filled approximately 2 inches deep with small stones. The inner ring is then set on top of those stones. You’ll have to do a bit of trial and error to ensure the tops of the inner and outer rings will be level when they are completed. Once the inner and outer rings are in place, fill the 3-inch void between the rings with more stone.
The Weber Smokey Joe grill may come with legs attached. If so, unscrew the three connecting screws and set aside the legs. In an amazingly beneficial coincidence, the Weber grill is perfectly sized to slip right into the inner circle of the pit and just enough lip remains above the surface of the pit for the cover to fit tightly in place.
Once the Weber is in place and you start a fire, it would be difficult and perhaps hazardous to adjust the lower air vent of the grill. So, set the vent opening however you want before you put the grill in place. I set ours about half-open and it works great for creating nice, small fires.
And when the cover is put on and the top vent closed, the fire will go out in very short order. If you want or need more or less bottom air for your fire, you can easily remove the grill to adjust it between fires when the unit is cool.
Get out the graham crackers, marshmallows and Hershey bars. It’s time to enjoy your fire pit.
You can view more photos of this project on my original Instructables post.
Photos by Dewey Lindstrom