What to Put in the Bottom of a Metal Fire Pit

Sitting around a fire pit and sipping drinks with your friends is great, but taking care of the fire pit isn’t as enjoyable. We may ask: “What do I put on the bottom?” or “Should I replace my metal fire pit?” These are just some of the questions people ask themselves.

The most common choices for fire pit bottoms are sand, gravel, concrete plates, or stone. Sand and gravel are cheaper, but they retain water. Concrete plates and stones are popular, more expensive, heavier, and may be too heavy for many metal fire pits, causing them to break.

In today’s article, we’ll look at metal fire pits, their best bottoms, and how to take care of them to ensure they keep us warm for years to come.

An image of a Fire pit with a view of the Catskills mountains.

What Is the Best Base for a Metal Fire Pit?

The best base for a metal fire pit is either a thin slab of concrete or stone that’s not heavy enough to break the metal fire pit. This way, water won’t stay in the fire pit (it will evaporate quickly), it will be easier to clean than sand or gravel, and it looks good.

There are several options for a fire pit base, and they’re all equally as good at first glance.

The first options are sand, gravel, or a combination (gravel on top of sand).

  • Sand is cheap and easy to come by. Many people simply find it bleak and uninspiring.
  • Another option is gravel, usually spread on top of the sand, making a double layer. Sand and gravel are usually more challenging to clean than concrete plates, making them less awesome of a choice, at least in our opinion.

Other options are large stones or concrete blocks to put at the bottom of the metal fire pit. They are the most attractive options. They’re also less likely to retain water if they get wet.

Even after heavy rain, water evaporates from stone and concrete very quickly, while gravel and sand retain it for a while.

Stones and concrete blocks have a massive flaw, though – they can be too heavy for a metal fire pit. They’re an excellent base for a built-in fire pit, but a heavy concrete base can break the bottom of a metal fire pit.

It’d be great if you found a thin concrete plate, but large and heavy concrete plates can destroy your fire pit.

Does a Metal Fire Pit Need a Liner?

Metal fire pits do not need a liner if fired bricks are the outer material. Suppose the outer materials are not fired bricks. In that case, a liner will increase the firepit’s longevity, as the liner’s materials can withstand fire and keep the decorative exterior from scorching.

Generally speaking, the pit will need a fireproof liner, depending on the materials we are using to make the outer rim of the fire pit. Some materials aren’t suited for hot temperatures. While they won’t catch fire, they can crack under extreme heat.

Most bricks and stones will crack after some time, although we must note that it could be years before something creates a vital crack. Some materials, such as fire bricks, are cured to withstand fire and can burn for decades before needing replacement.

Another thing that we must remember is cleaning – fire leaves marks on brick and stone. If using a liner, we won’t need to clean much since liners are usually dark.

If you skip a fireproof liner, know that your bricks and stones will be covered with black scorch marks. It’s mostly an aesthetic issue, but it can shorten the lifespan of your fire pit, too.

Should I Put Sand in the Bottom of My Metal Fire Pit?

Putting a thin layer of sand below a marble or a concrete plate is a good idea. The sand cushions the plate, ensuring nothing breaks. Putting sand on top of the plate would make the plate worthless, though.

Aside from that, sand isn’t beneficial unless we plan to use it as the base of the pit. People love to use sand for the base as they can use it to put the fire out and because it’s cheap.

Consider this, though; wind can lift and throw sand around, leaving us with the cleanup, and we’ll also have to buy new sand. Sand is also bland from a decorative perspective and retains water when wet. This can make starting a fire harder if it’s lit after a rainy day or a rogue sprinkler.

An image of a Fire pit on a campfire site.

How Do You Keep a Metal Fire Pit from Rusting?

There are two essential things we must do to prevent rusting. Firstly, cover the fire pit with a waterproof cover when not using it. This costs nothing (except for the waterproof cover), and it will minimize moisture. Then, use a specialized heat spray on the metal.

Using a heat spray on the metal, as the University of Wisconsin-Madison suggests (source), is a great idea, even in dry areas. Heat sprays coat the metal with a layer of a heat-resistant solution. This minimizes the fire pit’s heat damage and lowers the chances of developing rust.

It would be good to point out how important it is to keep a metal fire pit from rusting. Rust is terrible for two reasons; it turns the fire pit into an eyesore and diminishes the metal’s quality. Okay, three reasons: a rusted firepit will break sooner!

This applies to all metal, not only fire pit metal lining – gutters, for example, can easily rust if not taken care of properly.

Should I Put Rocks In My Metal Fire Pit?

Making a rock circle around the fire doesn’t achieve anything practical (we are no safer from a raging fire since the fire pit is already encircled), but it can make it more beautiful if done correctly.

It’s common to make a rock circle around the fire when lighting it up in the wild. That is the easiest way to prevent a disaster. We can also use rocks as a base for the fire pit or as a means of circling the fire.

Are rocks necessary? Not at all. Can they make a fire pit look better? Definitely!

Sand is a great base – just put rocks on top of the sand, and you have a great base for a fire.

Can I Get a Metal Fire Pit Bottom Replacement?

It is generally better and safer to buy a new metal fire pit and bottom replacement than to repair an existing pit or bottom. Old pits and fire bottoms can be welded back together, but they will require regular repair thereafter.

In most cases, this doesn’t make much sense because a metal fire pit is an investment we must renew about once a decade. A new, unused fire pit will last longer than the old firepit after welding it back together.

It’s likely that with years of use, the bottom of the fire pit will break open or become damaged. In that case, we’ll have to replace it.

So, if you believe that the fire pit is nearing the end of its life, you’ll probably decide it’s easier to buy a new one instead of welding the old one back together.

Because of the inferior longevity of metal fire pits, many people prefer concrete and stone fire pits. Admittedly, stone fire pits can’t be picked up and moved to another location, but they can last for decades before any renovations or repairs are needed.

Metal fire pits are often at a disadvantage because the bottom of it is often ‘hanging’ in the air. If we put rocks in it, we might overload it, and the metal bottom could break.

Therefore, it’s important to buy a fire pit made of sturdy metal that won’t break easily. These fire pits are naturally more expensive.

Fire Pit Cleaning and Maintenance

After washing the metal pit with water, clean it with a dry rag. A metal fire pit is prone to rusting if it stays wet. Consider treating the metal, depending on the metal type. Spray the metal with heat spray per the heat spray’s recommendations.

Once the fire’s been put out and the ashes have cooled down, throw them away and wash the fire pit with a wet washcloth or a garden hose. This is easy if we have a concrete plate for the base, as we can take it out.

We’re less lucky if the pit is sand or gravel because we have to scoop it out before cleaning and put it back in when done.

If it is a cast iron fire pit, we can use steel wool to wash it, and it won’t ruin the steel surface. Unfortunately, we can’t say the same for steel.

Problems arise when things melt and stick to the fire pit – plastic is the most common culprit. Make sure not to put plastic (such as cups) on or near the fire. If something falls in, try to pull it out with a stick before it melts.

There’s only so much we can do for a fire pit regarding maintenance. If we can move it, keep it in a covered place when it’s not in use (such as in the garage).

If that isn’t possible, cover it with a waterproof cover (as explained in the ‘How Do You Keep a Metal Fire Pit From Rusting’ section).

Additionally, use a heat spray. When it comes to heat, remember that metal can develop rust with sudden cooling (source), so don’t put out the fire with water if you can avoid it. It will diminish the strength of the metal by doing this.

Instead, let it die out naturally. At that point, the metal won’t be as hot, and then you can sprinkle a bit of water on it to ensure the fire’s out – without damaging the metal

An image of People sitting around a backyard fire pit.

Key Takeaways and Next Steps

Metal fire pits are easy to use and care for, and you’ll likely be using your pit for decades if you don’t forget to clean it and protect it from rain regularly. When it comes to the best metal fire pit bottom – sand and gravel are traditionally used.

Concrete or stone plates are better but can be heavy and break the bottom of the fire pit. Because of this, most people choose sand as the least invasive option.

Of course, remember to follow general fire safety recommendations, like these from the University of Utah healthcare system, when lighting up a fire pit.

That way, you won’t have to worry about your fire pit, your family, or anything else. Except maybe how to keep your deck from getting scratched up by the furniture. But don’t worry – we’ve got you covered there. Check out article, How To Keep Deck Furniture from Scratching Any Deck, next.

Resources

Learning from your own experience is important, but learning from others is also smart. These are the sources used in this article and our research to be more informed as homesteaders.

  • “Effect of Cooling Rate on the Corrosion Behavior of Duplex Stainless Steel After Solution Annealing Treatment.” Research Gate, www.researchgate.net.
  • “Fire Pit Safety Tips.” University of Utah Health, healthcare.utah.edu/healthfeed/postings/2018/07/firepit.danger.php. Accessed 19 Sept. 2022.


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