Segmental fire pit light tan precast concrete

Outdoor living seems to be the catchphrase on all the home and garden tv shows these days – that, and “Staycation” – but this isn’t such a new concept – Family BBQ’s, a new pool, or a couple of loungers on the unmowed grass have been part of most people’s summer plans for a lot longer than HGTV producers would have us believe.

Fire, however, has made some strides in the last couple of years. We had a chiminea – that wonderful Mexican clay fireplace – 25 years ago on our first apartment’s deck (wood framed building, trees overhanging the deck, lots of young people and too much wine; what could go wrong?) We’ve also had wood burning fire rings and propane fire bowls. But an actual fireplace in the yard always seemed like something only the wealthy had.

That’s changing, though, with the popularity of home improvement and landscaping shows on TV. It seems everyone wants to get in on the backyard fireplace craze. 20 years ago, the only way to do this was to build it yourself or hire a mason.

 

If you were handy enough, this was simply a few days work, but if you weren’t, you had to hire a masonry contractor. These days, a mason will build you a fireplace for somewhere around $8,000.00 to $10,000.00. If you have a high-end home, that’s not an issue, but what if you’re looking to significantly upgrade your suburban backyard, and don’t want to blow your entire budget on just one part of the project?

Fortunately, there are now a number of options when it comes to fire in the backyard. Unfortunately, plenty of these options are being banned in many BC areas – in fact, throughout most of North America, burning wood in an open container is rapidly becoming illegal. Gone are the days in most cities – and in many rural areas – that the old steel drum can be used for burning leaves and branches after a good yard clean up. A spot on the gravel in the backyard, open fire pits, my old friend, the chiminea – burning any kind of wood without a grate over the top of the fire is slowly disappearing. Even provincial and state parks have, to some degree, severely limited open fires.

But, back to the “fortunately” part – there are a number of good options open to those of us who still want a fire in our backyards. Fire pits, fire rings and the like – whether they burn natural gas or propane, or you can use firewood – are a great, small, and inexpensive way to bring a little firelight into your backyard.

But if you are interested in something a little bigger – a real feature of your backyard landscape – maybe you are considering a fireplace. There are quite a few ready-made fireplaces on the market these days, ranging from the simple upright steel units – reminiscent of chimineas – to the indoor style; something that looks like it was taken out of grandma’s house. Prices on these tend to be around $300.00. There are less expensive models (about $100.00) – you get what you pay for – and more elaborate models (in the $700.00+ range) that come with pilot lights (for the gas models) and remote controls.

There are also a number of precast concrete “kits” – a series of concrete pieces that either pin or mortar together, or interlock to form a finished fireplace. Solid and substantial, these fireplaces will cost between $1,500.00 and $3,000.00 and are usually quite a bit larger than some of the Big Box retail store models – more like a real fireplace, as opposed to a firepit with a cover or doors.

Four years ago, I wanted to make an outdoor fireplace for my family’s cabin down in Birch Bay, Washington. As a precaster, I thought that by making my own, I could get exactly what I wanted, and we would then have a new product line. I spent a fair amount of time online, researching designs so that I could make some moulds and precast a fireplace in sections that we could assemble onsite.

My first thought was to make a shell that could then be clad in stone. I could line the inside with firebrick, or cast the concrete using a fire-resistant mix; using refractory cement, along with lightweight aggregates which would allow the heat to dissipate without cracking the concrete when we had a decent sized fire going.

There were also a number of precast concrete fireplaces available – some were quite nice, but large, heavy, and no word on whether they used refractory cement in their mix design.

The problem with heat and concrete is that when you heat concrete up and let it cool, small pieces of the concrete tend to spall off the surface. Spalling is when small pieces of a larger material split off the surface. Sometimes, with concrete, explosive spalling can happen – that’s when the pieces violently spit off the surface. Usually, this is a small spitting or popping, however, it can actually be in much larger sections and can be quite dangerous. Not something that typically happens with a concrete firepit or fireplace, but, much like salt damage – which is a whole other story – over time, concrete + heat + cooling = rubble.

In some cases – such as a fire bowl or firepit, where extreme heat is not up against the surface of the concrete, using polypropylene fibers (a common concrete reinforcement) can help. The plastic fibres melt in the concrete, creating small vents for the heat to dissipate, much like lightweight aggregates such as expanded shale and pumice do in a refractory cement mix design.

While scouring the net for images of concrete outdoor fireplaces, Mirage Stone came up more than once. I visited their website, and the design – simple, linear, easy to put together – made me think that I could probably make something very similar here.

I then started researching refractory cement and mix designs. Simple enough, but there was a learning curve. It was clear that after I came up with a design, I would still have to make a couple of units, let them properly cure, and then heat them up to see if they would crack. At best, I was in for some experimentation and a couple of thousand dollars – but then I’d have a new product line, plus my own fireplace.

Then I started looking at how I was going to put this whole thing together. If I used fasteners, they had to be stainless steel or they would rust.  If I used mortar, it would have to be refractory mortar. I spoke with some masons and discovered that there was a steep learning curved here as well – at least for a layman who curveconcrete, not masonry. If I was going to get it right, there would be some luck involved, but if I was going to sell this to customers, there couldn’t be any luck involved, it had to work. There were some heat resistant epoxies available, but they weren’t perfect, they were messy, and if I ever wanted to take the thing apart and move it, it would be as easy as moving the chimney on my house.

So I figured, “Why reinvent the wheel?” – and I decided to buy a Mirage Stone fireplace. I called Mirage Stone, and talked for quite a while with the owner, Jim. The more I spoke with him, the more I realized that he had really done his homework. Precast concrete fireplace kits were gaining ground in the United States, but Jim had figured out how to make one that solved a number of problems:

  • He used refractory cement – his fireplace take the heat; light a fire in the winter and they simply won’t crack or spall like regular concrete.
  • He created an airspace inside the fireplace between the fire chamber and the outside – they don’t get too hot on the outside. (mine was too close to my cedars the first year – they survived; so did my marriage)
  • He made it so the parts interlock – no mortar, fasteners or glue. Anyone can assemble it. and if you want to move it later, simply take it apart and put it together again in the new location.
  • He kept the parts manageable – the concrete pieces are not so big that you have to hire a contractor.
  • He used lightweight materials – the fireplaces weigh less, cost less to ship and can be installed by two people in 45 minutes (I did one by myself just to prove it could be done by one person)
  • He added a spark arrestor in the chimney – with virtually no sparks, another fire hazard is eliminated.
  • He added an oven rack and a series of slots to adjust the height of the rack – you can cook in this, technically allowing it to be called a BBQ (some cities allow wood fires in cooking appliances only)
  • He found propane and natural gas kits that can be added later – if you change your mind (or your city changes it for you) and you want gas – drill two holes in the concrete (or order the fireplace with the holes pre-drilled) and install the kit. CSA and UL approved with pilot light.

Mirage Stone makes one product – an outdoor fireplace – and they do it well. I was so impressed with what Jim had told me during our conversation that I flew to Arizona and visited the plant – I saw an entire production run, minus the adding of a “secret ingredient” – not really secret – it was Portland Type 10 cement – but the exact amount and time it was added is what makes Jim’s incredible mix kick off really quick; they can pour a form twice a day without accelerators or steam, and the resulting concrete is not only refractory – heat resistant – but it is incredibly strong, allowing for thinner walls that do not crack as easily as regular concrete. He won’t share this mix design, and I don’t blame him. It’s some kind of voodoo magic.

I left Arizona as a new Mirage stone dealer. I bought my first semi-trailer load of fireplaces – one was for me – and I have never regretted becoming Western Canada’s sole distributor of Mirage stone outdoor fireplaces. I now have two of them, one at the cabin, one at home, and we use them a lot.

I have sold quite a few truckloads since that day. I’ve got more if you want one – and I keep bringing them up from Arizona – but even if you don’t, good luck with your fireplace. Ours have really added to our enjoyment of our outdoor living spaces.

Shameless plug: see our Mirage Stone Outdoor Fireplace Website (www.outdoorfireplacesbc.com) for more details, including our FAQ page for sizes and weights.