An outdoor fireplace can be a fantastic addition to any outdoor space. Not only does it provide heat and light, but it can be a great gathering place for your outdoor activities. While there are certainly some fireplaces that come pre-assembled, there’s nothing stopping you from building one on your own. In this article, we’ll walk through the steps and show you how to build an outdoor fireplace. The assembly is a labor-intensive process, but it is certainly an achievable goal.
Building an Outdoor Fireplace
Gather Your Supplies and Prepare
Every good project starts with gathering your tools. If you’re going to build a fireplace for your outdoor space, you’ll want to make sure that you have the following on hand:
- Rubber mallet (dead blow)
- Level (4 foot and torpedo)
- Fireplace kit OR bricks
This guide assumes that you’re going to use one of many fireplace kits, but you can do it all on your own by ensuring that you have the correct amount of brick, stone, and fire-resistant brick on-hand to complete the task. Note that your needs are going to vary greatly depending on the size of your fireplace, so we’re going to work from the assumption that you’re using a fairly common kit for the job.
Since this will be a fireplace with a chimney, you’ll also need to check to make sure that you won’t run afoul with your HOA or any local code enforcement agency. Doing so should only take a phone call, but it’s a great way to ensure that you’re not going to get fined.
Get Your Foundation Ready
Before you start building your fireplace, you’ll need a place for it to sit. You can’t just build your fireplace on dirty; a good fireplace of any style needs a firm foundation on which it can stand. If you already have a concrete patio, you should be in good shape for this step. If you do not, you might want to think about custom-building a foundation for your new backyard fireplace.
So, what kind of foundation are you going to need? Most swear by a four to an eight-inch thick concrete pad, reinforced to ensure that it can bear the weight of your fireplace. This is going to be a very heavy structure once it is done, so don’t fool yourself into thinking you can pour a couple of inches of regular concrete and be done with the whole process.
It’s very important to remember that you are going to be building this fireplace in steps. Every step needs to be followed exactly and in order, or you’re going to end up with the kind of structural problems that generally cause an outdoor fireplace to fail. Take your time with each step – one of the great things about building this kind of structure is that you don’t have to put it all together at once. As a note, though, this is definitely a project to undertake in mild weather as it is going to be fairly physically taxing.
Placing your foundation blocks is both the easiest part of putting together an outdoor fireplace and perhaps the most important. This is going to be the bottom of your new fireplace, so any problems that you have with aligning your blocks here are going to have a domino effect on what the rest of your fireplace is going to look like.
The most important thing you can do here is to keep the foundation level. Lay a couple of blocks, adhere them together, and then check to make sure that they are level. Continue this process until you have the entire foundation laid flat. It’s hard to overstate just how important it is to keep checking to ensure that this part of your fireplace is level, as even a tiny change away from being completely flat will end up having disastrous consequences for the rest of your build.
This is the step when your fireplace is actually going to become a fireplace. For the most part, you’re going to keep doing what you’ve done before – you’re going to build up, carefully adhering the stones to one another until you have reached your ideal height. Where things change, though, is in the creation of the box itself.
You’re going to use your square here, both to build up the fireplace and to ensure that your start placing your fire bricks in the right places. These heat-resistant bricks are a must for extending the life of your fireplace and for basic safety, so don’t try to build without them.
Note that you’re also going to be building a lintel at the front here, which is easier said than done. Your kit will have a piece for you to use that will give you some support, but you’re also going to use temporary support blocks under the lintel area to keep it steady until the pressure from the finished fireplace is able to keep it in place.
You are going to take a break – at least an hour, but possibly more – here to allow your adhesive to set, but then you’re going to move on to building your smoke chamber. The good news is that there is nothing here that’s quite as difficult as building the lintel in the firebox. The bad news, though, is that you’re going to start building up so it might be time to grab your ladder.
Your smoke chamber is going to be situated a little differently than the firebox. While you are definitely going to need to make sure that the stones in the backstay flush with what you’ve built already, the rest of the stones are going to be moved in about two inches from the exterior of the other stones. You’ll build up your firebox a little bit like a pyramid, bringing each layer in a couple of inches so that it reduces the amount of space on which you’ll be building your next layer.
Chimney and Cap
Now you’re at the big part – the chimney. While you might have been able to finish your smoke chamber without getting off the ground, this is the part that’s going to put you up in the air. Despite the height, though, building the chimney is really just a matter of confidently building up your fireplace tightly and on the level.
The most important thing you’re going to do here is to keep your blocks level. Every layer of the chimney needs to be checked with your leveling tool to make sure that the chimney doesn’t suddenly start to the slope. Slow and steady is the name of the game here, even though it might feel like you can rush.
Once you’re done with the chimney, you can add your cap. Placing your cap is very simple in theory but it’s actually hard in practice. It’s always recommended that you take this step on the day after your fireplace is finished, both to allow adhesives to dry and to give yourself time to rest. Carefully carry this piece up to your ladder and attach it so that it is centered on the top of the chimney.
This part is entirely optional, but it is what you’re going to do to make your fireplace look nice. If you’re building from a kit, you’re going to have a number of light finishing stones that you’ll use to round out the top of the chimney and to build the mantle on your lintel. Almost everything you’re doing here is for a show, but it does still make sense to take your time with each step.
Don’t forget to remove those support stones from under your lintel before you move on. Your fireplace should be able to hold itself up if you did everything correctly, so these stones are just going to be in your way. Once you are finished, you can finally enjoy a fireplace that you built with your own hands.
Frequently Asked Questions
How much does it cost to build an outdoor fireplace?
The cost of building an outdoor fireplace is going to vary greatly depending on a number of different factors. Not only is the size of the fireplace going to play a role, but so too is your choice between sourcing all of the materials on your own or using a fireplace building kit. Building an outdoor fireplace on your own averages a cost of around three thousand dollars, though those who are especially thrifty and who build smaller fireplaces can get away with spending well under two thousand dollars. It is, however, entirely possible to spend well in excess of twenty-thousand dollars if you choose to use more expensive materials for your project.
Can I build my own outdoor fireplace?
You can absolutely build your own outdoor fireplace. There are not only many plans available for doing so, but there are actually kits made just for that purpose. Though you will need tools and a lot of patience to get the job done, the truth is that building your own outdoor fireplace is a great way to get an excellent outdoor accessory for your home without having to spend quite as much money. With that said, this is a major construction project and it is not one that should be entered into without some forethought.
Do you need fire brick for an outdoor fireplace?
You’ll definitely need fire brick for your outdoor fireplace. This kind of brick plays a very necessary role in helping to insulate the outer bricks of your fireplace from the heat of the firebox. The fire brick also does a great job of helping the interior of your firebox look great, so it’s a helpful addition for anyone who cares about the aesthetics of his or her outdoor fireplace. Whether it’s safety or aesthetics that have you concerned, you’ll definitely want to make sure that you have these bricks on hand for your project.