Patio / Terras Fireplace



Introduction: Patio / Terras Fireplace

In this instructable I'll explain my adventure making a fireplace in my garden patio. The steps involve a bit of metal fabricating and some unconventional ways to make your own double-walled or double-jacketed chimney pipe. Playing with fire is a lot of fun but can be dangerous. Please note that I tested my setup at different stages throughout the building process. Whatever I came across that deemed unsafe to me I improved in my own way. I like to make things cheap or for a fraction of the costs that you would be paying normally. Still some parts I made for this build are perhaps better bought in quality store. And some jobs of this build are perhaps better left to a real professional.

Materials I used:

  • 3mm steel plating
  • Thick mesh steel plate
  • Fire resistant black spraypaint
  • Cheap chimney pipes 3x (1 meter long, interlocking, 15cm diameter)
  • Spiral pipes (I had a left over from a airconditioning system, 12,5cm diameter)
  • Chimney cap
  • Ornamental stone

Step 1: Fabricating the Fireplace Itself

Sadly I don't have a lot of pictures of the fabricating process because a friend of mine who is a professional welder did most of the work. The diameters where 70cm wide, 40cm in height and 40cm deep. This made for a pretty big fireplace but that's just the way I wanted it to be. On the only one photo that I have of the fabricating stage you can see that the 'roof' of the box is flat. After a good old test fire it became apparent that a flat roof didn't work because of the smoke development inside. The result was that the smoke came out of the large front opening and started up filling my patio instead of going through the chimney and into the open air. *COUGH-COUGH*

We tried to fix this by remaking the flat roof into a pyramid shape. This way the smoke gets channelled to the chimney a lot better. It was a bit fiddly to weld a round shaped chimney connection on top of the pyramid shape but we managed. This round connection is slightly smaller than the diameter of the chimney pipe so it fits in snuggly in there.

We also added a trimming around the front opening for looks and some edges/railing for the barbecue rosters. The lower raster is for the fire to be placed upon (so air can get underneath) and the upper one is for grilling/cooking. Hopefully the second photo gives you guys a better visual explanation.

When the welding part was done I grinded all the edges smooth and sanded the whole thing down. Then I gave it a few coats of fire resistant black paint.

Step 2: Setting Up the Fireplace

The next stage is to install the fireplace at the right spot, making the surroundings fireproof and installing the chimney. Chimney piping is super expansive especially when you want it double-walled (double-jacketed). The top part alone (the part on top of your roof) costs about 700 euros. I avoided this by making my own piping. I tested this and it's all safe and sound although it's a bit unconventional. Note that I gave my chimney and end cap a few coats of fire resistant black spraypaint.

Firstly I put the fireplace on a base at the desired height. I used a few blocks of stone left over from a planter box I made earlier. I didn't fix this in place because the ornamental stones I would be using later would hold it all together.

When I was sure about the right spot (and got full approval of the missus) I started cladding the walls with heat resistant boards.

Then I installed the chimney. I used a rope and a heavy nut to pinpoint the hole that needed to be cut in the roof. I made the hole a bit bigger than the diameter of the chimney. It's important that the wood doesn't touch the piping so I left a 2cm wide gap between the two. To brace the chimney I used the heat resistant board. I cut out a two 50x50cm squares and made a hole in the middle through which the piping fits pretty snuggly. I screwed one board directly on the ceiling of my roof exactly underneath the premade larger hole. The second (duplicate) I screwed down on top of my roof. Then I could run the chimney through it and down on top of the fireplace.

To be sure this was enough to prevent dangerous situations I tested the fireplace while drinking a few beers with me mates. It turned out the chimney got red hot just above the fireplace and overall it wasn't really safe in my opinion. To fix this I took a smaller diameter spiral pipe and fitted it within the chimney pipe to create a double-walled or double-jacketed pipe. I used small blocks of heat resistant board as spacers. After I put the pipe in place I filled the gap between the pipes with play sand from my kid's sand table. This acts as an insulator. Now I am able to touch the chimney without burning my hands immediately.

Lastly I glued on the EPDM rubber on the roof to close gap between the chimney and the roof. This was a messy job and definitely not the best way to go about but it worked for me. I used heavy duty sealant for this. I also put a small cap on top of the chimney to prevent rain getting in. In the last photo of the chimney you can see the cap. There is only 3cm of clearance between the cap and the chimney. I later put the cap on a bit higher so the clearance was about 7cm. This greatly improved the smoke being pulled through the chimney.

Step 3: Ornamental Stone

Okay now that the fireplace is fully functional the ornamental stones can be put in. The stones I used are called flagstones here in Holland. They are rather expansive to buy. For a big one you pay up to 50 euro’s per stone. Smaller ones go for 10 to 20 euro's. This adds up quite fast!

Luckily some guy in my town wanted to get rid of a very long old pathway in his garden. I had to pay 25 euro's if I did all the labour. We'll that was a golden deal in my book. I wasn't sure what and how many stones I bought but I had to drive up there 3 times with my trailer! The stones you see in this build are like 1/4th of all the stones I had. Most of them I gave to my dad to make a large waterfall in his fishpond.

I was planning on using cement to hold them in place but when I was puzzling out which stone went where I noticed the little wall I made was 'rock' solid. I decided to just keep on building up my wall. It’s difficult to explain how to do this. It’s like a giant jig-saw puzzle. I just started and tried different stones and selected the best fitting one. I made a piles per shape and size. Ugly ones where put in as fillers, a bit out of sight. Weird ones I kept apart and used them in a nice way. I had one sticking out that seems like a natural shelf where I could put a candle on. Some curved nicely around the fireplace so they went there. It’s just something you need to take your time for.

Step 4: The Result

I'm pretty happy with the result and I can tell you guys a fireplace makes the patio a much nicer place to be in! It's just super cosy with some good music on the background. I already drank quit a lot of beers with my friends while watching that hypnotising fire!

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