42" corner build, Devon

[Baldywills]

So I finished cutting the insulation board and marked out and cut the oven floor bricks. It turns out my brand new brick pile has two different height of bricks, they differ in height by around 2mm. In the pictures where I have laid out the bricks dry you will see the difference in height which I have now rectified and replaced bricks to get a more level cooking floor.

Top tip - take photos of the oven floor and take the opportunity to expand and enlarge the photos as you will see more anomalies than with the naked eye.

I have moved the oven floor into position, completed the soldier course before the rain came (again) and it looks like I have a decent week of weather ahead of me so I hope to move forward with the build.

Gary

[Baldywills]

Soooo, my build stalled for a number of months (OMG 8!!) due to work commitments. I think I have now got my time management sorted and can get cracking on finishing the dome. Since my last post in June 2024 I did complete some works on the kitchen, namely putting up a canopy over the whole kitchen, I have also completed the reclaimed brick facing, completed the BBQ, plumbed in the sink and had a granite worktop installed. Also the patio has been laid all around the kitchen - not by me.

I binned the idea of polishing the concrete worktop. I didn't make the concrete hard enough on the pour and as I was polishing I was just getting grit coming up. I could have done another pour with specialised concrete but it would have increased the height so I opted for some granite worktop. The extra expense was unwelcome but the result is stunning. Once the dome is complete and painted white it will have a beautiful contrast with the worktop.

I did change the design and composition of the BBQ area and lined it with spare calsil board, I may have to put a hood over the bbq area to protect the wood canopy.

I shall upload a batch of photos showing the updates to now.

Looking forward to finishing the dome which I shall be starting this morning, I do have a deadline for completion for the end of May as I have been nominated by the village to host a big party.


Ready for photo overload?

Gary

[Baldywills]

some pictures from July showing the patio and the completion of the canopy - the canopy is a car port by design but covers the kitchen area nicely

[Baldywills]

These next photos show the brick facing work and the fact that my casual board got wet so I have to number and remove my oven floor - what a pain in the rear that job was!

[Baldywills]

Some pictures of the BBQ area, dry layout first then going firm on the size and construction method.

[Baldywills]

Some pictures of the "not arches" between the brick piers. I decided not not do arches as it would cut down on the size of the openings, this reduction in size was mainly due to the height of the patio slabs being higher than expected.

The span was covered using angle iron and an iron bar that has supported the half bricks, the wood support was kept in to keep the strength in the short term. The brickwork will not have any pressure from above as it will be covered by a granite slab.

Pictures of the granite worktop to follow which will explain all.

[Baldywills]

Pictures of the making of the template for the granite worktop. It was interesting watching the guys work to prepare the plastic template.

[Baldywills]

First batch of worktop pictures, sorry for the overload but I think this looks fab.

[Baldywills]

Second and final batch with Wifey and granddaughter no1 in one of the pics. Finished article from all angles.

The next phase was to cover the top of the BBQ wall with granite. Will update pics soon.

Gary

[Toiletman]

Second and final batch with Wifey and granddaughter no1 in one of the pics. Finished article from all angles.

The next phase was to cover the top of the BBQ wall with granite. Will update pics soon.

Gary

Nice kitchen, looking forward to seeing the oven finished!

Two questions:
- Did you waterproof the granite already? I understand you need to impregnate it to ensure you don't get water stains in it.
- What's the material underneath your oven floor, in between the calsil and the bricks?

[Baldywills]

Nice kitchen, looking forward to seeing the oven finished!

Two questions:
- Did you waterproof the granite already? I understand you need to impregnate it to ensure you don't get water stains in it.
- What's the material underneath your oven floor, in between the calsil and the bricks?

Yeah the granite top is sealed and been highly polished, shouldn't have to do it for a year.

I don't have anything between the bricks and the calsil. I have oven floor bricks, 3 layers of calsil sat on the reinforced concrete floor- of which it contains night time storage heater blocks (as heat sink).

[david s]

Having insulated under the floor particularly well, I noticed that you have not insulated under the oven dome bricks. Is there a particular reason for omitting insulation here because a significant amount of heat will be conducted into the supporting slab and apart from the heat loss could cause problems with your granite that sits on top of it, because granite is renowned for not liking heat. It might not be too late to insulate under them and prevent some possible problems before starting the dome proper.

[Baldywills]

Having insulated under the floor particularly well, I noticed that you have not insulated under the oven dome bricks. Is there a particular reason for omitting insulation here because a significant amount of heat will be conducted into the supporting slab and apart from the heat loss could cause problems with your granite that sits on top of it, because granite is renowned for not liking heat. It might not be too late to insulate under them and prevent some possible problems before starting the dome proper.

Hi David, I have not sat the soldier course on any insulation as most of the soldier course is not going to be in contact with direct heat from the fire and any heat will have the entire length of the brick to traverse down towards the concrete base which then also has a pretty solid heat sink.

The granite worktop has been cut shy of the dome by 50mm so will be protected from any heat as I plan on having insulation all around the dome in several layers of vermiculite, blanket and covered in a render.

I think I understand the point you are making about heat dissipation but I much prefer the soldier course to be laid directly onto the concrete slab to give a solid construction base rather than sat on an insulation board.

[david s]

Ok. Heat travels in three ways, by convection, conduction and by radiation. It doesn’t care what direction it travels by conduction and will travel faster the higher the material’s thermal conductivity is. The thermal conductivity of standard concrete is only slightly lower than dense firebrick, resulting in heat readily transferring to the very large thermal mass of the supporting slab (heat loss)

[david s]

Hi Gary,

If you are still set on laying the first row of bricks directly on the supporting slab, here are a couple of suggestions you might consider. Because thermal expansion at around 400C is around 0.5%, it translates to about 5 mm/m which can easily be enough to break the bond between the base of the dome and the cooler supporting slab on which it sits. The frequent expansion and contraction cycling of continued use exacerbates the problem. For this reason as well as the heat loss, builders have opted to insulate the total oven, both under and over it. As well as creating an expansion joint between the gallery and outer decorative arch, or between the dome and gallery. Here are a couple of things to ponder.

Firstly, laying soldiers as a first course introduces the problem of creating long vertical joints between the soldiers. Because the most vulnerable part of any hemisphere is at its base (think of an eggshell cut in half). Cracks in domes are common and invariably originate from the base. Many builds using soldiers use a steel band around the soldiers in an effort to reinforce the base. This is a difficult operation, especially across the oven mouth and introduces corrosive steel. A better solution is to use two half brick courses instead of the soldiers, so the mortar joints are staggered, eliminating the long vertical joints.

Secondly, if the first course of half bricks is insulating fire brick, rather than dense fire brick, it will insulate the base of the dome very well.

I love the detail on your build by the way. Did you abandon the concrete polishing in preference to the granite?

Dave