Leicestershire Brick Oven

[alexlea]

Hi everyone

Thought I'd sign up to get some inspiration and advice for my brick oven build this year. My best man built a brick oven in his garden and I was obscenely jealous, so when we moved to a new house and had some space, I decided to take the plunge!

I've built the box base out of sleepers which I'm in the process of packing with old bricks a foot or so from the top of the box. I'm planning on pouring a 4" concrete base on top of the bricks, then around the same again of perlite, then a layer of firebricks level with the top of the base. I'm going to run some fire-resistant tape along the inside edge of the sleepers to help protect against the heat from the oven.

I've managed to pick up approximately 200 refractory bricks that a steel fabricators were giving away for free that I'm planning on using for the dome. They're made from silica/ quartz/ cristobalite mix and should cut into three to give me some nice sized blocks to build the dome. Might take me a few cutting discs, but they were free, so I've got a few quid to play with.

I'm planning on using Vitcas for most of the materials; firebricks, arch, outdoor oven cement and fireproof tape. I was going to insulate the dome with ceramic fire blanket, chickenwire, prelite mix, then a final cement render.

Any suggestions, guidance or general advice would be very much appreciated.

Thanks in advance

[enkindle]

Hi Alexlea,

Great to hear you've started a build.

If you're pouring a 4" slab and then a similar depth of perlite then I wouldn't expect enough heat to get to the sleepers to need the fire resistant tape. My current oven has a similar base setup and the underside of the slab only gets slightly warm to touch even after a long firing.

For the 200 refractory bricks you were given, are these soft or hard bricks?

Soft firebricks are light weight (significantly lighter than a standard house brick) and provide good insulation but are not mechanically strong. They are typically white or cream coloured. They could be used for a wood fired oven dome but they won't store much heat and this will probably limit use of the oven to live fire cooking only. They definitely shouldn't be used for the oven floor as they don't have the abrasion resistance needed to survive on the floor.

Hard firebricks are much heavier (probably twice the weight of a standard house brick) and they absorb and store more heat than soft insulating bricks. They are typically a yellow / orange colour. An oven built with these will need a slightly longer firing to get to temperature but it will then maintain the temperature for longer and if well insulated allow residual heat cooking making the oven much more versatile. The main problem building with these is that they can be really hard to cut. I use an angle grinder with a 9" diamond blade and always soak the bricks in water before cutting. You can dry cut them but the blade will last a fraction of the time.

Your idea to insulate the dome with ceramic blanket with chicken wire to hold in place and a perlite mix with final render sounds spot on. What are you planning for a flue?

[alexlea]

Apr 25, 2023 23:17:51 GMT enkindle said:

Hi Alexlea,

Great to hear you've started a build.

If you're pouring a 4" slab and then a similar depth of perlite then I wouldn't expect enough heat to get to the sleepers to need the fire resistant tape. My current oven has a similar base setup and the underside of the slab only gets slightly warm to touch even after a long firing.

For the 200 refractory bricks you were given, are these soft or hard bricks?

Soft firebricks are light weight (significantly lighter than a standard house brick) and provide good insulation but are not mechanically strong. They are typically white or cream coloured. They could be used for a wood fired oven dome but they won't store much heat and this will probably limit use of the oven to live fire cooking only. They definitely shouldn't be used for the oven floor as they don't have the abrasion resistance needed to survive on the floor.

Hard firebricks are much heavier (probably twice the weight of a standard house brick) and they absorb and store more heat than soft insulating bricks. They are typically a yellow / orange colour. An oven built with these will need a slightly longer firing to get to temperature but it will then maintain the temperature for longer and if well insulated allow residual heat cooking making the oven much more versatile. The main problem building with these is that they can be really hard to cut. I use an angle grinder with a 9" diamond blade and always soak the bricks in water before cutting. You can dry cut them but the blade will last a fraction of the time.

Your idea to insulate the dome with ceramic blanket with chicken wire to hold in place and a perlite mix with final render sounds spot on. What are you planning for a flue?

Hi enkindle

Thanks for the reply and comments. I was planning on building the oven directly on top of the hearth built into the top of the sleeper base, just because the sleepers were cheaper and easier to build than a brick base and reinforced concrete slab! I used the article below as a starting point but will obviously build a brick dome rather than clay:

www.deliciousmagazine.co.uk/how-to-build-a-wood-fired-pizza-oven/

I'm filling the inside with tightly stacked bricks and just thought it would be good to pour a concrete layer on top of the bricks as a base, then perlite insulation, then firebricks to create a level floor. I was going to make sure the internal edge of the oven was well inside the firebrick floor but thought a bit of extra insulation to protect the sleepers wouldn't hurt. I've obviously cut out the sleepers in front of the oven entrance and set some fire bricks in there to avoid charring the wood!

The firebricks are very dense and heavy and don't cut easily with a bolster, but I was planning on cutting halfway and then finishing off with a bolster so I have one clean edge to work with. It sounds like they were cast by the company themselves using a premix. I was going to do a test cut over the weekend and see how I get on.

Hadn't thought too much about the flue at the moment, but might look into some kind of steel stovepipe with a cowl as it will be near the neighbours fence so don't want smoke drifting over!

I'll keep you updated! All the best.

[enkindle]

Thanks for the link, a picture definitely helps.

I think a layer of concrete on top of the bricks is a good idea to provide a stable base for the insulation and firebricks. No matter how well you stack the bricks they are likely to settle a bit and without the concrete your firebrick floor could end up uneven.

Something to consider at this stage is making sure you have the correct height for the oven floor which is generally recommended to be at the elbow height of the main user. Getting this right makes a big difference to avoid stooping when using the oven.

For the flue I like to use twin wall stainless steel. It can be expensive but you can often pick up it up used or as a second.

[alexlea]

Apr 26, 2023 23:09:58 GMT enkindle said:

Thanks for the link, a picture definitely helps.

I think a layer of concrete on top of the bricks is a good idea to provide a stable base for the insulation and firebricks. No matter how well you stack the bricks they are likely to settle a bit and without the concrete your firebrick floor could end up uneven.

Something to consider at this stage is making sure you have the correct height for the oven floor which is generally recommended to be at the elbow height of the main user. Getting this right makes a big difference to avoid stooping when using the oven.

For the flue I like to use twin wall stainless steel. It can be expensive but you can often pick up it up used or as a second.

Fantastic, thanks for the advice. Off to Wickes this weekend to get the concrete! Perlite has arrived too, so with any luck I can crack on over the bank holiday.

I'll definitely keep an eye out for a flue. I want to get the base all done, then I can give some time to the final dimensions, how it will all fit together and how to add the flue.

All the best

[alexlea]

Started a build progress thread here:

ukwoodfiredovenforum.proboards.com/thread/3702/leicestershire-brick-oven-build-progress