To get around the problem I put a piece of strong insulation foil I had lying around the garage on top of the sleepers. Apparently it is all to do with steam and moisture being drawn out of the dough, just look at all the pizza stones you can now buy. It’s probably the easiest to build due to its rustic look and round design. Once I had the shape of the oven floor drawn, I laid my fire bricks on top of this in a herringbone pattern. A word of warning this is a very messy job, with dust everywhere. Once the oven is at the correct temperature it only takes a couple of minutes to cook a pizza so I decided on a base size of Y x Z. I built the oven floor by first laying the bricks on the base I had previously built. You also have to consider the heating time, the bigger the oven the longer it will take to warm up. I decided I needed room to cook just one pizza at a time with enough space to have a fire still burning at the same time. Everything is supplied (apart from sand and cement and 16 concrete blocks) so you can build a pizza oven that you can be proud of. The point of using firebricks is to soak up and hold the heat from the fire. You also need to think about what you are going to use the oven for, just pizza’s or for cooking a Sunday roast? I should say that when I brought my original fire bricks from Vitcas, they were perfectly straight with good right angles. Best Clothes, How do you cut Flower pots when building a Tandoor, Making Tarte Flambee or Flammkuche for a family party, Getting ready for my next Pizza Oven Build in the shape of a dragon, Using Sand for Insulation in the Tandoor - SimpleNick. Introduction 2. I only had a limited space and I needed to make the floor as large as possible, leaving 3” on the outside edge of the wall for insulation and final protection layer. I look back at my old oven and wonder how I ever managed to cook in such a small space. Hands Up – I cocked up here”, Getting ready for my next Pizza Oven Build in the shape of a dragon, Using Sand for Insulation in the Tandoor - SimpleNick. Most pizza oven build guides talk of making a wooden frame, pouring in the mix, and letting it set hard. I should say that when I brought my original fire bricks from Vitcas, they were perfectly straight with good right angles. This was a poor design for the base and I will tell you why. Insulation I mention about wanting to make the cooking floor as large as possible, well that was the best decision I made. Hands Up – I cocked up here”It would be easy for me to rewrite the above section to save face, but I will keep it here so you can learn from my mistakes. Any questions on this part of the build or if you want to share your experiences with a similar build, then use this link to contact me or select the contact tab at the of this page. Click to see them in more detail. There are lots of references on the Internet to the correct size for the oven floor and all are different. I decided to stick with the original plinth and wooden base– NO! As I say “there is nothing wrong with making a mistake when doing something new, as long as you learn from that mistake”. Medium duty firebricks are comprised of roughly 35% alumina and 50% silica, heat up quickly, easily withstand the 900F heat your oven will reach, and are designed for the rapid heat-up and cool down (thermal cycling) that your oven will experience. I have now decommissioned this oven and will soon work on oven number two, with superior insulation for the base. This now brings us to the size of the oven floor. I was convinced over time the sand would fall through the cracks in the sleepers. I put the hose on it and it was soon out. Lay the oven floor tiles loose on top of the plaster sand bed. Yes you’ve guessed it! To decide the floor size, I simply laid a series of bricks where I saw the wall would be and then drew in pencil on the fireboard. 3. I got the thickest boards I could find with a 1000C max service temperature. This is because you build on top and around the base. Outer Layer 7. They weren’t cheap, but I am glad I did as they make all the difference. Next I was concerned that the sand would pierce the insulation material and the sand would still drop through into the cracks so I then put down some pressure treated wood on top, this time going in a perpendicular direction to the direction the sleepers were laid. The idea being to pour concrete into the frame to create a simple retaining wall for the vermiculite. Now the Vermiculite mix, but first here is a tip for gardeners. I had four lying around and it just seemed the obvious choice. So you guessed it, I abandoned my original idea and decided to buy proper fire bricks. Also I now have a solid firm base with excellent insulation properties. Unfortunately I didn’t have much left so I used good quality kitchen foil (but don’t tell the wife!). Also how much do you want to cook at a time, for instance do you want room to cook several pizza’s? Well I completely underestimated how hot these ovens get, two of the sleepers got so hot they started to smoulder. When I say simple, I mean simple, just rough pieces of wood (pressure treated) screwed into the base. You might have noticed the missing rectangle in the top of the slab, this is for the "insulating concrete" that will be under the brick oven floor. But more importantly, one of the success factors to a good pizza, is the surface you cook on. 1. 4. It needs to get hot enough to give that all important crust. You also need to think about what you are going to use the oven for, just pizza’s or for cooking a Sunday roast? OK, you are now ready to make the oven itself which can be found here Core Oven. For this part I used 200L of vermiculate to create an insulation base of 6”. If you think about it, the size of the oven floor ultimately defines the size of the whole oven. Lessons Learnt Protecting the Oven I ignored all this information and went with what worked best for me. We want this insulating layer so that we don't waste time heating the whole slab when using the oven. Now came the simple bit, I just bedded it on top of a mortar mix, making sure I kept everything level of course. Once I had the shape of the oven floor drawn, I laid my fire bricks on top of this in a herringbone pattern. I also decided to put a thick layer of vermiculite as a sandwich between the wood and the insulated fireboard. This also has the added advantage of bonding the base sleepers together. Next I set several Calcium Silicate boards on top of the vermiculite to create another fireproof insulation level. The set for this oven were not so good, which meant I had a lot of gaps in my herringbone oven floor. It wasn’t a major fire but I was no longer able to use the oven. If you think about it, the size of the oven floor ultimately defines the size of the whole oven. I was always going to have to cut bricks for the walls and roof, so it made sense to cut the base as well. Also how much heat would I loose through the base. Fire bricks make excellent abrasive resistant floors, such as those found on the Hearths & Floors of Pizza Ovens , wood ovens, Kilns, furnaces and other applications. This is the brick that we recommend for both the cooking floor and dome of the Pompeii brick oven. This is where is didn’t work for me. Design So what went wrong? You don't have to use vermicrete, but please put some form of high-temperature insulation (cal-sil, foamglas, Insblok 19) under the floor. 5. A 100L bag from a fire stove store cost £19 – go figure! I had used the oven the night before and the next morning I came down to see a small smoke trail coming from under the oven. 1. If you're looking to build a high-mass floor for bread baking, you'll still want to isolate the heated mass from the structure of the base. Hands Up – I cocked up here. Oven Floor “That last statement is complete and utter rubbish! The set for this oven were not so good, which meant I had a lot of gaps in my herringbone oven floor. Base 3. More importantly I was going to do a proper job with insulation. Once all the bricks were cut, I set the floor on a bed of one part fire cement and one part sand mix. True, but the wooden top was still sound, even if it did have a hole burnt through it. Our Firebricks are 38-42 Grade and can withstand temperatures up to 1400 degrees Celsius. Having a lot more space to cook with makes things so much easier. For a pizza oven, firebrick directly on the structural slab is *the* formula for insufficient floor heat and/or excessive fuel consumption. I should point out that I was using firebricks for the base, walls and dome. The last thing I did was brush fine sand in-between the bricks to lock and hold them in place. Living with the Oven 6. I poured in the mix, levelled it, and then left it to set for a few days. Next, I put the bricks back in the frame and slowly tapped them into the sand, making sure I had a completely flat surface. Just make sure your wife hasn’t put the washing out or you will be in the Dog House. You can also cook more than one item at a time, and also have a good fire going.