Daylight's UK 36" x 19" Pompeii build

[daylight]

Inspired by the Forno Bravo site, I have decided to help to spread the wood-burning oven craze to the UK. I am building a 36" diameter oven with a 19" high dome. The first course of bricks will be single upright 9" bricks. The original intention was to have an 18" elliptical dome but with only a 9" rise above the soldier course, this resulted in a worryingly shallow curve over a large part of the dome (see photo). Current thinking is that the dome will be part of a sphere that will provide a less shallow curve.

The oven will be sited close to the back door of our cottage to allow easy access during the Winter and those many cold and wet days that we have in this country! I am using a convenient space left by a redundant oil tank thus reducing the work needed for the stand. See photo. Extra supporting blocks were put in today and tomorrow we start on the frame for the hearth.

Martin.

[dbhansen]

Re: Daylight's UK 36" x 19" Pompeii build

Looks like a beautiful location, Martin! Good luck with the build.

[dmun]

Re: Daylight's UK 36" x 19" Pompeii build

The oven will be sited close to the back door of our cottage to allow easy access

I'm sure your building codes are different than ours, but remember that your chimney needs to be two feet higher than anything within ten feet, for close to house builds.

[Neil2]

Re: Daylight's UK 36" x 19" Pompeii build

I think your dome height is too high. A typical pompeii has elliptical shape with the dome height 85% to 90% of the radius, or in your case 16 inches high. To facilitate this I would use a 4 1/2 inch soldier course.
The ellipse does not "sit on top" of the soldier course - it sits on the hearth. You start curving "catching up" to the elliptical shape from the top of the soldier course.

[shuboyje]

Re: Daylight's UK 36" x 19" Pompeii build

Personally I would bevel the top of the soldier course and use a catenary segment for the dome if you want to go this approach instead of a hemispherical shape, it's what I am doing on my 30" oven, and so far so good.

[daylight]

Re: Daylight's UK 36" x 19" Pompeii build

Many thanks all for your advice.

Demun - A very good point about the chimney height. Our building regs are the same as yours - 2ft higher than buildings within 10ft. Fortunately, the cottage extension at that point is only a low single storey and it will be easy to exceed the required clearance.

Neil2 and Shuboyje - I will take another look at the ellipse drawn from the floor level rather than the top of the soldier course but I am not too concerned if my design is a little unconventional. My main use of the oven will be for bread, hence the desire to have a 9" soldier course that will give me more space at the edges of the oven.

Martin.

[jammyweb]

Re: Daylight's UK 36" x 19" Pompeii build

Martin

Where did you look up UK building regs for this? I only found planning permission details and concluded for the size, I did not need planning permission.

James

[daylight]

Re: Daylight's UK 36" x 19" Pompeii build

James,

I Googled 'chimney UK building regulations' and found a number of references, all of which seemed to give the same information. This link Flue outlet height, UK stove building regs J is one of them - condition 'D' applies to my oven because it is within 2300mm of the house. I also remember our plumber telling me about the regulations when he was installing a new boiler for us a few years ago.

You are quite correct about the planning permission - that is not required but building regs are another matter .......

Martin.

[daylight]

Re: Daylight's UK 36" x 19" Pompeii build

Here are a few posts to catch up with progress.
I was able to use two existing block walls for the oven stand, adding a new block wall on the third side alongside an existing thin stone wall. On 17th August we completed the shuttering and waited for good weather to pour the hearth.
The two pictures show the shuttering under construction and completed. The new block wall is on the right. The shuttering was made entirely using scrap wood from a friendly local builder.

[daylight]

Re: Daylight's UK 36" x 19" Pompeii build

It has been an awful Summer in SouthWest England and it was a while before we were able to pour the hearth. The first photograph shows the rebar in place and the first pour about to happen. We put more rebar in than recommended mainly due to the large unsupported gap over the wood store underneath and the overhang over the flower bed on the right.

[daylight]

Re: Daylight's UK 36" x 19" Pompeii build

After marking out the floor, we laid it on a mixture of fire clay (from cutting firebricks) and sand together with some bought fire cement.

[daylight]

Re: Daylight's UK 36" x 18" Pompeii build

A change of design! As can be seen from the title, I have decided on a dome height of 18" rather than the originally intended 19". This now conforms with the 'high vault 36" diameter' suggestion in the Pompeii Oven Plans. Given concerns in the forums (and from my DIY building guru, Les), I have also decided to use a half-brick soldier course rather than full-brick ones. The dome will have an elliptical cross-section.

Many thanks to Gromit for his idea of a form using a rotating vane. My form consists of a section of thick ply cut with rounded ends to fit a 36" diameter circle and a width that will allow it to be removed through the oven entrance once the dome is complete. The ply has 6 castors (furniture glides in the US?) attached underneath and a thin metal post going through the centre point. The post goes into a small wooded block mounted on a thin ply circle (36" diameter and in 3 sections for removal) that sits on the oven floor. The two elliptical vanes were cut to achieve the dome height of 18" and were bolted to the marine ply 'skateboard'. The vanes will drop very slightly when unbolted and this should enable them to be removed once the dome is complete. The idea of having two vanes was to allow two bricks to be set at the same time, especially on the higher courses where they may need support. The jury is out on whether two vanes are a good idea as it certainly makes the form much more difficult to make. I will let you know once I have used it in anger. The form rotates really easily and looks as though it will work really well but the proof of the pudding is in the eating!