How to Build An Outdoor Fireplace With Cinder Blocks

How to Build An Outdoor Fireplace With Cinder Blocks

An outdoor fireplace is a great place to enjoy and gossip with loved ones. Many people think that it is impossible to build an outdoor fireplace by their own effort. But it is not that tough. Do you wanna know how to build an outdoor fireplace with cinder blocks? This article will provide you with information and processes step by step about how to build an outdoor fireplace with cinder blocks.

The outdoor fireplace makes the house more expensive and classy. It creates an amazing atmosphere and eye-catching look. You can enjoy your winter gossiping in the backyard if you have an outdoor fireplace there.

You may find it costly But if you know the tricks, then it will not cost you much. Basically, an outdoor fireplace means a freestanding fireplace, manufactured of cinder blocks, stones, concrete, mortar, metal, ceramics with an enclosed burn chamber, solid or screened opening and chimney with spark arrestor. A perfect outdoor fireplace increase the house value and enhance the beauty.

Your fireplace should be built accurately. Just mixing the blocks, bricks, concrete and mortar together and building an outdoor fireplace is not a proper process. If you need perfection, then put your best effort in it. You need some tools, equipment and measurements for building an outdoor fireplace. Besides, you need to plan your desired structure for an outdoor fireplace and select a perfect pattern before starting the building process. As you are investing your money for an attractive outlook, you need to be careful.To ensure a perfect outcome and safety, focus on the pattern and process.

Check The Rules And Codes Given By The Authority

Before you decide to build an outdoor fireplace, You need permission from the building authority. Check the ordinances properly. You may talk to the authorities directly about this matter. If they have no issues with building a fireplace, then you can confidently start the process. But you need to be assured about the codes first. Not skip this.

You have to know the permissions you need and how much it will cost to Have the permissions.You should know the rules and prohibitions Of the city you live in. Ask the insurance authority if there will be changes in the deal of home insurance premium if you build an outdoor fireplace.

Uses of Cinder blocks

Uses of Cinder blocks

Outdoor structures are mainly built with cinder blocks. They are technically adjusted with the terms. They are weather friendly. 

Generally people build pizza ovens, fireplaces etc using concrete blocks. Depending on uses and purposes, you can buy cinder blocks of different shapes. They can Be found in different shapes and sizes. If you measure the needed amount and size, then pick the cinder blocks that you need.

There are taller, smaller, narrow and wide many types of shapes. You can even buy cinder blocks having holes if you need. You will find that they are sold by inches. So before you go to the shop, You need to know the required measurements Of cinder blocks that you need to build the fireplace.                               

Cinder blocks are not costly. You can buy them at reasonable prices and they are highly available everywhere. So you can use as many Of them as you need. If you can build your fireplace at a low cost, it will be highly profitable to you. Cinder blocks are the best option for this. They have great quality and low price.

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Plan the Building Process

Like other projects, building a fireplace also needs some plan. As you are eager to know How to build an outdoor fireplace, You need to know how to plan. Planning is a very important part. Before digging the area, you need to do some work. You need to plan the shape, style and then you need to pick a spot where you want to build. So the process needs to be planned before execution.

Pick A Spot

This is undoubtedly a major and important part. You have to decide where you Want to build the fireplace. It should be built at least 15-18 feet away from home. Backyards can be an amazing option. But before locating the place, you need to observe the surroundings and choose a wide place. Outdoor fireplaces are the perfect place of enjoyment and chilling. So select a place which is calm and comfortable.

Plan the Pattern of the Fireplace

Before knowing how to build an outdoor fireplace with cinder blocks, you need to plan the pattern. As you are going to build an outdoor fireplace, you must have desired patterns planned in your mind. You can build your fireplace in any style you want. The pattern should look beautiful. It will enhance the glow and beauty of your home. It will also enhance the value of the house. You can place the firebox over the fireplace. The design you decide should be creative. You can plan an artistic design for the fireplace. The fireplace is wood burning type mostly. But if you want you can connect the gas line to make a fire.

Required Equipments and Accessories

Knowing the list of needed accessories are essential as you are learning how to build an outdoor fireplace with cinder blocks. So if you Want to build your fireplace on your own, You need to buy some tools and equipment. The list of the tools are given below:

  • Cinder blocks
  • Mortar
  • Hammer
  • Assembled stones
  • Cement board
  • Chimney chase cover
  • Water
  • Concrete
  • Scoop
  • Screwdriver or pliers
  • Stubborn concrete
  • Cold chisel
  • Measuring tape
  • Drill
  • Veneer
  • Hearth blocks
  • Concrete trowel
  • Brick etc.

So, these are the basic materials. You may need more tools according to the design you choose. You can easily buy these products and tools from hardware shops.

Decide the Dimension

Before digging the soil, you need to decide the dimension. Generally, outdoor fireplace sizes are the same like indoor fireplace. But you can choose the dimension and size you want for your own fireplace. According to the disired size, you need to excavate the area. First decide the dimension,  then mark the decided area. After that, you need to excavate the marked area.

Start With The Foundation

To build an outdoor fireplace, you need a strong foundation. You can try building the fireplace in an existing concrete-based platform,  but it will be better if you build a new concrete pad considering the purpose of building a fireplace. This foundation will hold the structure, so it needs to be built perfectly. 

 First of all, You need to excavate the soil in perfect size. So you can place a measuring tape to dig in the perfect size. You don’t need to dig much. Excavate upto 4×6 inch depth to find subsoil. You need to dig a 12 percent larger area than the dimension size. But you need to be ensured that there should be no water line or gas line pipe on the selected area.

You need to level the soil after digging. Flatten the soil using a spade. The steps on how to build an outdoor fireplace with cinder blocks are being given step by step. keep reading.          

Make Layers of Crushed Pebbles

After leveling the soil, you need to create layers of crushed gravel. Put the crushed peebles over the flattened soil. Make 2-3 inches layers with crushed peebles. These crushed gravels will create a strong base for the concrete pad. 

Crushed gravels are kept under concrete pad to secure extraction. Otherwise water may damage the concrete base. To avoid that situation, you need to make 2-3 inches of layers with crushed gravel. You can mix crushed bricks with crushed gravels to create the layers as well. After making the layers, you have to flatten the gravel layers. Level it up and start the next step.       

Pour the Concrete and Create The Concrete Pad

Put a wooden rectangular-shaped structure over the gravel layer. The shape should be 2% larger than the dimension. The wooden structure is made of wooden boards. Make the concrete mixture properly and pour it on the structure. The concrete amount should be measured before pouring. Pour the perfect amount so that the concrete base is 7-8 inches thick. To ensure a long-lasting strong supported base, this thickness is needed. 

Leave the concrete for 72 hours to set. It gets strong within one or two weeks. But the entire basement gets securely set after one month.   

Construct the Fireplace Base With Cinder Blocks

Once the concrete pad is ready to support the structure, start building the main base with cinder blocks. Cinder barrier need to be connected with mortar. Follow the steps that are given below:

1. Build the First Layer

Make a thick layer of mortar over the concrete pad and place the cinder blocks in rows. Make sure that the cinder barrier should be square and placed perfectly in that row. You need to place them properly. Don’t hurry at all. Put them one by one in order over the mortar layer.

2. Apply Mortar Over The First Layer of Cinder Blocks 

Once the first layer is completed,  you have to apply mortar over it. Make a layer of mortar over the cinder blocks. You need to level it. Otherwise the build up won’t be perfect. 

3. Make The Next Layer

Just like the first layer, follow the steps in the second layer. Put the cinder blocks offsets so that the cinder barrier of this layer are over the joints of two cinder barrier under it. Keep repeating the layers with cinder barrier until you reach the desired length. The layers can be two or three-sided depending on the pattern you choose. Observe the blocks while making the layers. 

If there is any hole or fracture, then you need to fill it with mortar. Thus you will have a smooth soft finish. In every layer, the level of the cinder barrier should be square and perfectly placed. After that let it rest to be secured. Cut the half portion of the last block to create a smooth finish.

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Attach Fireplace Blocks

Once the layers of cinder blocks are perfectly set, you need to place hearth blocks over them. Just like the previous steps, you need to create a layer of mortar over the cinder block layers. Then place the hearth blocks in a row perfectly. Keep them straight and after placing them, you need to level the blocks. The layers of fireplace blocks are mostly three-sided to keep the place warm.

Attach Fireplace Blocks

Layering of hearth blocks is a similar process like the layering of concrete blocks. Create hearth walls with cinder barrier maintaining the square shape. First apply a coat Of mortar, then let it dry for 24-48 hours. Now put the first layer of cinder barrier,  then apply furnace bricks mortar over it and then again assemble the blocks offsets so that each blocks of the upper layer is put in between joints to connect two blocks under it. Keep repeating the process until you reach your desired height for hearth walls. Hearth brick mortars are used to create a heat proof fireplace.

Create the FireBox

The Middle part of the fireplace is called the firebox. It is the very place where the fire will be made. So you need to decide the material of the firebox. Fireboxes are generally made with hearth bricks. You need to put a layer of stubborn strong mortar in the inner part of the firebox. The firebox must be extreme heat proof. As the bricks are not costly and highly available,  it is a good choice.

As you are learning how to build an outdoor fireplace with cinder blocks, you need to know all the options. You can also create a firebox which is metallic. You can buy or order a firebox which is made of stainless steel. But it will cost you a lot. Moreover, you need to build the entrance part of the furnace according to the shape and size of the metallic firebox.

Put a Chimney Chase Cover On the Top Of The Hearth Walls

Once you reach the desired length of the hearth walls, then apply a thick layer of mortar over it. Let it dry then put the chimney cap on it. The chimney cap will support the fireplace walls. The chimney cap is the protection part of thefurnace which saves the furnace from rain water, dewdrops and keeps the flame protected when there are extreme wind blows.   

Create a Beautiful Outside Appearance

Adding a beautiful surface is the last finishing touch. It will express your creative thoughts. You can keep it simple by doing a plain plaster or installing natural stones. You can also create the veneer with manufactured bricks or stones. The design will enhance the beauty of it. You can also put a wooden frame covering the outside of the fireplace. The exterior design is absolutely up to your choice. Just try making it beautiful and classy with your creative thoughts. 


Places Where You Should Not Build Your Fireplace

When you choose the place where you want to build your own fireplace, You need to avoid building it in some specific places. The places you Should avoid are given below:

1. Avoid Trees  

Never build your fireplace in front or beside a tree. If there are any trees in the surroundings of the furnace, then don’t build the furnace there. It can be dangerous.

2. Water Lines and Gas Lines

Be sure about the surface where you are building your fireplace. Before digging,  ask the authority and check properly if there are any water lines or gas line pipes under the place. If there are any lines, then don’t even excavate the place. Excavation may cause complications.

3. Avoid Power Lines

As you are going to build a fireplace, avoid the areas where there are power lines. Fire flames need to be kept away from power lines. Otherwise, accidents may occur.

4. Keep it Away From Buildings and Fences

You need to build the fireplace at least 15-20 feet away from any building surrounding it to avoid any kind of accidents. You need to keep in mind that the fences should be far away from the furnace. Be careful about that. Otherwise, the beautiful furnace can be the cause of distress if you are not careful about the prohibited facts.

Make Fire With Gas

You can make fire in the fireplace according to the way you choose. You can Make a fire by burning wood or you can connect a gas line with it to Make a fire. But if you want to make a fire with gas, you need the help of professionals to connect the furnace with gas lines. But burning the woods to make a fire is always a better choice.      

Benefits Of Building An Outdoor fireplace

An outdoor fireplace creates an intimate cozy vibe. As you have already learned how to build an outward furnace with cinder blocks, you should know the uses and benefits as well.

Building an outdoor furnace will definitely increase the demand of your house and along with that it will increase the beauty of your house. Outward fireplaces are the best excuse to throw parties. You can place a tent in front of the furnace and spend a romantic night there with your partner. 

Building An Outdoor fireplace

Outdoor fireplace is also the best place to hangout and chill with friends and bbq parties. The place will not only be the reason for chilling but also keep you warm in the cold weather. You can enjoy warm cozy moments having a cup of coffee in that zone. Doesn’t it sound thrilling? It is the best way to keep yourself warm and enjoy winter in the Best way.                                   


Outdoor fireplace is always a thrilling and cozy warm place to enjoy. In this article we have shown you the steps in details about how to build an outdoor furnace with cinder blocks. Hope you will find it useful. Outdoor fireplace motivates our thinking towards a positive vibe. It gives us a comfortable feeling and great enjoyment. Enjoy your cozy furnace area with friends, family and loved ones. Don’t forget to let us know your opinion through your valuable comments. Enjoy your day!

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