Keiths 32" build in north yorkshire uk

[kstronach]

Hi all,

So ... after months of planning and reading i have finally started construction of my oven!!

Firstly thankyou to every one who has helped so far and hopefully a few will follow this build and chip in along the way with suggestions and tips and answer questions i'll no doubt have!!

ok so the build is a 32" pompeii oven made mostly out of reclaimed materials i have managed to source through work and off friends, who i must note are probably sick to the back teeth of listening to me go on about the oven all the time!

the dome its self is going to be constructed of solid clay reds on a storage heater firebrick hearth built with a lime mortar mix and insulated with vermicrete then rockwool then more vermicrete and a stucco igloo finish.

ok i'll pop some pictures up of where i'm up to and see what you guys think!!

keith

[boerwarrior]

Re: Keiths 32" build in north yorkshire uk

good luck Keith!!

I am building a 32" Pompeii - which seems to be small relative to most others on this forum. I just got done with the dome - next is the chimney and outer arch.

My build is here: http://www.fornobravo.com/forum/f8/3...nia-19283.html

I will follow your build!

Neil

[kstronach]

Re: Keiths 32" build in north yorkshire uk

so heres where im up to so far got the block stand built on an existing flagged slab the shed was sat on as you can see that has now been rotated round to make way for the new arrival!!

then i've set lintols across the blockwork and bedded on 4 2 foot by 3 foot 2 inch thick concrete flags with one cut in half lengthways in the middle to give me a working area of 59" by 72"

around the edge of this i have bedded a brick which i'm going to infill with vermicrete, i have room for 3 3/4" will this be ok? annoyingly i ran out of mortar with 2 bricks to bed!!

the block stand is going to be faced with red brick at some point to but not yet! i'm going to try and get some more reclaimed reds to match! it will probably just get rendered for now to tidy it up!

hopefully these pictures will upload so you can see what i'm waffling on about!!

[kstronach]

Re: Keiths 32" build in north yorkshire uk

good luck Keith!!

I am building a 32" Pompeii - which seems to be small relative to most others on this forum. I just got done with the dome - next is the chimney and outer arch.

My build is here: http://www.fornobravo.com/forum/f8/3...nia-19283.html

I will follow your build!

Neil

hi neil,

thanks! had a look through your build, very tidy build! nice stand aswell do you have building experience? unfortunately budget restrictions mean i couldn't afford a full firebrick oven so i'm making do with red clay solids i got reclaimed from a friends house when he ripped a wall out! firebricks are over ?2 pounds each down the local building supplies! how much insulation did you put under your hearth?

[boerwarrior]

Re: Keiths 32" build in north yorkshire uk

Wow that's expensive for Firebrick. My ones cost about $1.47 each which is a little less than a pound. One benefit of a smallish oven is that you don't need as many bricks. So far I have used about 120 bricks for the floor and dome - but I have wasted about 10 of them by not cutting carefully enough.

I've built some wood-framed structures but no brick building experience prior to this. I am learning and getting better as I go. My structure passes the "ten foot test" - get any closer than 10 feet and you start to see the mistakes!

I put a total of 3 inches of calcium silicate insulation board under the oven. That stuff is normally quite expensive but I got a great deal from a member of this forum. I also got quite a lot of thermal blanket (from the same guy) which I plan to wrap over the dome. I have no pizza-oven cooking experience yet but it sounds like good insulation is very important.

[boerwarrior]

Re: Keiths 32" build in north yorkshire uk

Keith

the one thing that worries me a bit about your base is the 2 inch flagstone surface that you have on top of the concrete block.

Do you think that will be thick enough and strong enough to hold everything above it?

Vermicrete has good compressive strength but poor "cantilever" strength. My oven so far weighs over 1,000 pounds. And it doesn't have the chimney built yet or the surrounding structure. All-in-all you will probably have close to 2,000 pounds that needs to be supported.

My 'hearth' surface is made of 6-inch thick high strength concrete (the same kind they use for kitchen counter-tops) with a whole bunch of re-bar in it set 6 inches apart.

Mine is probably overkill but I'm concerned yours may not be strong enough.

There are many others on this forum with way more experience so hopefully someone smarter than me will weigh in!

Neil

[kstronach]

Re: Keiths 32" build in north yorkshire uk

Hi,

I'm almost certain it will be fine, it's the pre stressed lintols set across the block work that are taking all the weight really and there spaced no further than 8 inch apart so even if a flag was to fail I don't think it could go anywhere anyway! I've seen a few ovens built this way over here with less lintols than I have put in with no problems I'm aware of! I'm going to put the vermicrete in tonight the leave it to cure till weekend then hopefully start on the dome! It's a bank holiday here this weekend so hopefully the weather will be good and I can crack on!

Keith

[boerwarrior]

Re: Keiths 32" build in north yorkshire uk

That sounds good Keith - sounds like you're on it!

It's often hard to see things from photos - I just wanted to make sure before you got too far.

Good luck!

Neil

[kstronach]

Re: Keiths 32" build in north yorkshire uk

thanks neil for pointing it out mistakes are easily made and hard to rectify later! i'm doubting myself now!!

a couple more pictures. i was going to pour the vermicrete under the hearth tonight but had an idea i wanted to run by people first!

i have got some kingspan (poly urathane) insulation from work and wondered if i could put that in first then a layer of 1 1/2 inch vermicrete on top to bring me up to brick level? i know its got good compressive strength and very good thermal insulation, not too sure about temps though or what sort of temps it would even be getting to down there under the bricks and vermicrete? what does anyone think?





also i have 2 100 litre bags of vermiculite will this be enought to do under my hearth? area is 50" by 62" and just under 4" depth. is 6 to 1 mix ok for this slab?

regards

keith

[boerwarrior]

Re: Keiths 32" build in north yorkshire uk

I didn't use Vermicrete so I am not a good person to comment.... But I Googled "Xtratherm" and found something that says the maximum continuous working temperature is 100 degrees Centigrade - i.e. 212 Fahrenheit.

I think you will be way hotter than that under only 1 1/2 inches of vermicrete.

I think you would be better off using all vermicrete - the thicker the better.

[kstronach]

Re: Keiths 32" build in north yorkshire uk

Yea I think it's going to be all vermi I suppose if your in doubt about something it's probably not the right option!

[david s]

Re: Keiths 32" build in north yorkshire uk

Keith,
If you are using a fair amount of vermicrete you might be interested in the results of this test I did about drying the stuff.
Dave

[boerwarrior]

Re: Keiths 32" build in north yorkshire uk

I looked at Dave's drying data when i was considering using vermicrete - definitely worth a look. If I remember correctly somewhere on this forum someone has posted some data on the heat transfer through Vermicrete? If you can find that it would give you an idea of how hot it would get under 1 1/2 inches and whether it is OK to use housing insulation under that.

[kstronach]

Re: Keiths 32" build in north yorkshire uk

thanks both,

dave, thanks for that study interesting reading, so would you recommend leaving the slab covered for a week prior to starting the dome construction? and also do i need to mix it by hand or could a cement mixer be used for larger amounts?

neil, i think i've decided to drop the xtratherm now i'm not convinced its upto the job and not worth risking but i'll have a search for that thread it will be interesting to know how much heat will seep through as i have the concrete flags below which ideally don't want to much heat on them!

[kstronach]

Re: Keiths 32" build in north yorkshire uk

vermicrete put in this weekend i mixed using a cement mixer at a ratio of 5 - 1.

today i have made a form for the oven opening arch. i have gone for 16" wide by 10" high in an arch. will this be ok for my 32" oven size? height is ok i think not sure on width could i go wider? don't want to make it too big then lose heat!! what are your dimensions neil?