We have been posting informative articles on different types of fire pits, and we have also dished out a lot of opinions, recommendations, and suggestions on fire pits and their accessories. One of the questions that we have been getting is on how to build a fire pit on concrete.
Of course, we are not surprised. Building fire pits on concrete is an entirely different ball game. That is why we took the time to do some research to get our facts right before posting this article.
In other words, this article gives you all the necessary information on how to mix concrete to make it fireproof, and we also gave the necessary steps to building fire pits on concrete. In fact, that is the main focus of the article.
Some people believe that they can build their fire pit on any concrete floor. They told us that they already have a concrete floor that they intend to build their fire pit on.
As a matter of fact, you cannot build your fire pit on any concrete because it may not be fireproof. We will explain why you can’t build your fire pit on a non-fireproof concrete floor. Just take your time to read this article to the end. You’ll be glad you did.
How to Build a Fire Pit on Concrete?
1. How to Build a Wood Fire Pit on Concrete
For this topic, we will assume that you already have a fireproof concrete floor on which you want to build a fire pit. So, let’s start with a wood-fueled fire pit.
You should start by finding out from local authorities if you can build a wood fire pit in your yard. They may give you some restrictions. It will be too disastrous to have built it before you find out that a fire pit is not allowed.
Remember, ignorance is not an excuse. So, you can only move to the next step if you find out that a fire pit is allowed in your location.
Draw both the inner and the out circles, rectangles, or squares of the proposed fire pit, depending on your chosen shape. Remember that the walls of the fire pit will stand in between.
Based on the sketch, measure the dimension of the fire pit and calculate the number of bricks that you will need.
Now, you can arrange the bricks side by side for the first layer. After that, you can arrange the second layer on the first one. If you decide to go all the way to the third layer, you can arrange the third layer.
You can install a steel wall inside the pit.
Give the fire pit some time to get dry, and that’s all. What is left is for you to fill it with dry wood. Don’t forget that wet wood does not produce great fire.
All you need is dry wood. You can even take it a step further to chop the firewood into a similar size. This will make the fire burn smoothly.
2. How to Build a Gas Fire Pit on Concrete?
Decide on how to link your proposed fire pit to your main gas supply. Chart the route for the pipe. Measure the length.
Buy a pipe or some pipes, a burner, and a connector.
Connect your main gas supply to the pipe and run it to the spot where you plan to erect the fire pit. At the spot, you will connect the other end of the pipe to the burner in the fire pit.
Before you test-run the burner, it is important that you check for leakages. Wait for some minutes to see if you will hear any hissing sound. If not, you can pour some soapy water on both joints. Pour it on the joint between the pipe and the main supply where you tapped it.
Also, pour some soapy water on the joint between the pipe and the burner. Once you notice any bubbles, it is a sign of leakage. Seek professional help. If not, you can move on to the next step.
Open the valve slightly to allow gas flow and light the burner. This is just to test the burner. If you are satisfied with the flame, you can move to the next step.
Now, you can begin to build the fire pit. Leave a space for the gas line in the walls of the fire pit.
Sketch the walls of the fire pit on the concrete floor.
Based on the sketch, measure the dimension of the fire pit and calculate the number of bricks that you will need. Go and order the bricks.
Now, you can arrange the bricks side by side for the first layer. After that, you can arrange the second layer on the first one. Take the same steps for the third layer, if needed.
Leave the fire pit to dry up.
you can now fill it with some sand and lava rocks. That’s all.
For safety reasons, we will advise you to get a screen or spark guard for your fire pit. This prevents sparks and glowing embers from flying around. Also, your fire pit must be at least 10 feet away from any structure.
If your choice is a gas fire pit, you must check for leakage before lighting it every time. Always cover your fire pit when it is not in use to prevent the ultraviolet rays of the sun, the rain, and debris from penetrating it. Most importantly, never leave your children alone with the fire.
3. How to Mix Concrete to Make It Fireproof?
To mix concrete and make it fireproof, you need the following:
- Refractory cement
- Hydrated lime
You have to mix them in the ratio of 3:2:2:0.5. Gravel will take 3 parts, refractory cement will take 2 parts, sand will take 2 parts, and the remaining 0.5 part will be for the hydrated lime. Mix them together and keep adding water as you mix.
Continue to add water until when you are able to scoop out a ball of concrete as big as a snowball that doesn’t break down or fall apart. Then, your fireproof concrete is ready.
spread it where you intend to build the fire pit. Make it as flat as possible.
You now have to cure it by spraying some water on it.
Cover it with a plastic sheet for about 48 to 72 hours.
When it is dry on the surface, you can remove the plastic cover, but that does not mean it is dry internally. So, we will advise you to leave it for at least three weeks before you put it to use.
You can start building your fire pit after a few days, but make sure that you don’t light the fire until after three weeks of concreting the floor.
Why a Fire Pit Cannot Be Built On Ordinary Concrete?
We warned earlier that you should not build your fire pit on any concrete. This is because not every concrete floor can withstand intense heat for a long time. When you build your fire pit on a concrete floor that is not fireproof, it will begin to crack gradually. In fact, part of it can explode.
When the concrete on which your fire pit cracks or caves in, it will affect the whole of your fire pit. You may have to break it down and re-build it. Also, heated cement can explode, sending some pieces flying into the air. These pieces can go as far as 5 feet from the point of explosion.
Remember, the explosion will happen when fire is burning in the fire pit. That means that you and some of your friends or family members will be around by then. The flying piece of concrete could hit anyone.
That is the real danger. So, if you already have a concrete floor and you’re not sure if it is fireproof or not, call an expert to assess it. In the alternative, you can mix another one elsewhere.
If you have been reading this piece from the beginning, you would have learned how to build a fire pit on concrete. We outlined the steps involved in building a wood fire pit on concrete and the steps involved in building a gas fire pit. Also, we explained how to mix concrete to make it fireproof.
Most importantly, we have explained why you should not build a fire pit on any concrete floor that is not fireproof. We’re glad you took the time to read this, and we’re also sure that you’re glad you read it. Please don’t keep the knowledge and information to yourself. Share it.