$50 Fire Pit Using Concrete Tree Rings

Intro: $50 Fire Pit Using Concrete Tree Rings

We recently moved from the remote north woods of Wisconsin where people create great lakeside campfires by digging large fire pits into the ground and lining them with large rocks. We now live in a residential neighborhood in the Central Valley of California. Here, campfires are confined to pre-built pits or structures. People build only small controlled fires to minimize the risk of sparks blowing into neighboring combustibles when the fire is left unattended. These smaller campfires are also easy to extinguish, with less risk of embers continuing to burn.

Even with these restrictions, our family still loves to sit outside around an evening fire in the backyard. But we didn’t want to spend a small fortune on a pre-manufactured patio fire pit or a contractor built unit. We were also not sure where we might permanently want the pit 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 (circles that are used for flower beds at the base of a tree) on sale for $2 a section. We borrowed a tape measure and quickly determined that 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.

Materials:

• Weber Smokey Joe Portable charcoal grill or equivalent 14" diameter grill to be an insert in the rings ($30 new)
• 4 sections of 14" inside diameter concrete tree ring ($2 to $3 each = $8-$12 total) -6 sections of 24" inside diameter concrete tree ring ($2 to $3 each = $12-$18 total)
• 2 cubic feet of small stones, pebbles, road gravel or decorative rock ($0-$20 depending on how fancy)

Total cost: $50-$80 depending on your taste in stones.

STEP 1: Constructing the Inner Ring.

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 and 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/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" 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.

STEP 2: Adding an Outer Ring

We thought the 14" tree rings looked a little puny by themselves, so to give the fire pit more mass we surrounded the inner ring of 14" tree ring sections with an outer ring of 24" diameter sections. The sections are 2" thick, so the outer diameter of the completed fire pit will be 28".

Note that the 24" outer rings have a very convenient tab type 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.

STEP 3: Filling the Void

You will quickly notice that when the 14" rings are stacked inside the 24" rings that there is a 3" gap between the inner and outer rings. You will also notice that each 14" ring is about an inch shorter than each 24" ring. To solve both of these problems the outer ring is erected first and then filled approximately 2" 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 insure 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" void between the rings with more stone.

STEP 4: Installing the Weber

The Weber Smokey Joe grill may come with legs attached. If so, unscrew the 3 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.

STEP 5: Light It Up

Get out the graham crackers, marshmallows and Hershey bars. It’s time to enjoy your fire pit.

Comments

[ErikaA50]

I love the creativity, however, spraying grass and weed killer on the earth is not good. Those chemicals get into the aquifer, cause cancer, autism, and many other disorders. I work 6 - 7 days every week, am 56 years old, and STILL maintain my half acre by hand (hardcore landscaping such as digging up unwanted weed trees, grass, and weeds. No excuse for spraying that, when a shovel works just as well. You will also benefit from the exercise!

[dewey302]

Before you jump to conclusions in order to scold others for their indiscretions you might want to at least inquire as to the "weed killer" they used. In this case a little home brew of white vinegar, salt and castile soap. But do keep an eye on me. As my wife will attest, I have plenty of other faults you can show me how to correct.

[Jrd]

Where did you find the concrete tree rings? Especially the 14inch diameter ones

[1980slegofan]

We converted our rock beds to mulch with a natural live edge. I built this with all the stones we removed. Nice way to re-purpose edgers and river rock you may already have on hand.

[dewey302]

Great looking. Love the re-purposing of what you had on hand.

[J2B297]

I like this idea, but where the heck did you get the tree rings? All I have been able to find thus for is an 18" version and even then the options are slim (like 2 places and one doesn't even have it in stock)!

[Tcster725]

Love this cant wait to start project

[lisak187]

Won't the heat from a wood fire eventually burn through the grill?

[dewey302]

Don't know...I guess it depends on how long "eventually" is. I've been burning wood in mine for nearly 5 years. Even if it burned through next week (which it shows no sign of) these little grills only cost about $35 (the original cost $30). So no an outlandish investment. I'm guess rust will be the culprit before heat.

[Dragonfly411]

I have a 36" fire ring and I'm thinking of using these tree rings with rocks to fill between. so how many tree rings do I need to fit the 36" ring and the outside? I have some unused so not sure how many more I would need.

thanks

Jennifer

[dewey302]

I don't think that will work using the tree rings pictured in the Instructable. These rings have a fixed radius and thus can only make a circle of one size. The smaller rings make a circle with a 14" diameter and the larger rings make a circle with a 24" diameter. If you try to put them around a 36" circle (or larger) they will not create a nice circle. Rather it will be a ring with a very wavy circumference. I suppose they could be set up that way but I would question the stability of that sort of ring.

[dewey302]

I'm not totally certain I understand your question. Are you intending to build an inner circle of tree rings inside your existing 36" fire pit ring? If so, you would need 6 sections of the 24" I.D. ring sections...that's assuming you are going two high.

[Dragonfly411]

No first circle would be around the fire ring which is 36" diameter, then second circle with the rocks in between.

Thanks.

[boocat]

This is very clever. It looks great, too. Thanks for sharing.

[KellyW142]

I've looked everywhere I know to look for the tree rings and nobody is selling them. What the big box stores have done is realized people were building fire pits for $50 out of them, and now they are selling $250 fire pit kits. It makes me really angry they are taking advantage of this situation.

[tjharner]

Fire brick should be used when constructing fire pits. Ordinary landscape pavers/tree rings etc can get so hot they explode. Be safe out there!

[dewey302]

True, fire brick would be a better option assuming the brick is in direct contact with the flame and/or coals. Here, the fire is contained in the inner metal liner, the Weber grill. There is a generous air space between the inner circle of brick and the liner and the outer circle of brick is further insulated with a 2" layer of stone. There is also venting space between the upper and lower circles of brick so cool air is drawn in and exits at the top. I have many times tested the temperature of the inner circle of tree rings and have never had a time I could not place my hands or feet on the brick due to heat.

[kdavidson5]

Lowes has something similar to this in the "Edging Stones" category.

[stresuel]

I love this idea but am having trouble finding these bricks here in Canada as I've asked at Rona but not Home Depot yet. Any ideas where I can buy them,

Lorna

[WilliamM224]

Good luck finding the tree rings, I had to give up the search. Decided on building my own with materials I could find