Exterior Dimensions

[adm]

All,

I am trying to work out some sizing for slab and base to accommodate a brick built Pompeii oven. Could use some help....

Firstly, for the internal diameter, I am thinking of 900mm. Is this a good size? We have 5 people in our family and often have up to 12 or so total people around to eat. I have no problem catering for this many on two weber kettles today.

Next - what would be the outer diameter of a typical finished oven this size so that I can size my base, my blockwork and my slab?

I think the overall diameter works out like this....

900mm oven internal + 200mm for brick dome + 100mm for ceramic blanket + 150mm for vermicrete + 100mm for final render to give a total diameter of 1450mm or thereabouts.

Does that sound about right?

I'm not yet decided between igloo style external render, or building a brick enclosure - but if I allow 150mm for vermi and 100mm for final render, then that gives me 250mm (125mm per side) which would be large enough to build a brick enclosure around and fill with loose vermiculite, right?

If this is the case, then if I build a concrete base 4 blocks long by 4 blocks wide (440 x 215mm hollow blocks), then I end up a tad under 1800mm x 1800mm. Allowing for an external cladding of bricks over this takes me to around 2m x 2m.

So for the slab itself, if I allow another 100mm on each side, I get to 2.2m square. Does that sound correct for the overall slab size?

Still trying to draw this all up in SketchUp - which I have never used before....

Finally, how much space should I allow for the entry arches and oven landing? I quite fancy the idea of setting oven facing one corner of the overall base, with the corner of the base cut off diagonally.

Many thanks for any pointers.....

[faz]

Your calcs seem right to me for the dome.

Take a look at my build. I have the entry facing a corner, but I built a cantilevered extension to the slab to allow room for the entry/chimney. It is easy to do, just make sure there's plenty of rebar in there to support the weight.

My base was 3.5 blocks by 3.5 and my oven is 30 inch ID. There's only a small gap between the oven and the surrounding walls so it is quite a snug fit.

ukwoodfiredovenforum.proboards.com/index.cgi?board=pompeiiovens&action=display&thread=291&page=1

[adm]

Thanks Faz,

Yep - something just like the corner entry on your build will be what I go for (I think).

Lovely build - very informative and inspirational!

Cheers,

Alasdair

[tonyb]

Hi Alasdair, just one comment, if you go for an enclosure, you don't need the vermicrete to cover the ceramic blanket, loose vermiculite will be more efficient due to the increased volume of air gaps, its also quicker and easier

Other than that your calcs look reasonable. Don't forget about the entrance landing and flue, also when you start building make sure the oven is near the front edge of the slab as its difficult manoeuvring heavy pans at this working height.

[adm]

Thanks Tony,

I know I don't need the vermicrete if I do an enclosure - which is quite attractive to me as I think an enclosure would be more weatherproof long term as I don't want to be redoing render every spring! The downside is it makes the whole thing a lot bigger.

I have another question though...I know about the "magic formula" of 63% ration for door height to dome hight, but are there any other key ratios - for example door width to dome width, or length of landing?

[adm]

Still working on sizing.....I drew up the dimensions for a 1000mm internal diameter (igloo) oven in SketchUp:



I am not sure of how the entry should join the dome though (even only in 2 dimensions right now!). Does the above look about right? (This would give me an entry 460mm wide which would just allow me to slide through to do the internal pointing...

[tonyb]

Alasdair, your drawing is pretty similar to what I built, though I had probably less than 25mm of final render. In addition to the hemisphere you will need a short landing area to include the flue stack.

The keying in of the entrance to the door is an issue that all 1st time builders have, look at my building blog or some of the other examples on the forum for a better understanding.

I'm not aware of any other ratios regarding the dome build, its more down to practicalities of loading and unloading and what't the biggest item you want to cook. I think my door width is about 500 and I've cooked whole suckling pig on a couple of occasions. There is a recommendation regarding the flue size, but can't remember what that is.

One thing for you to be wary of, there is no single 'perfect' design, it doesn't exist. Thankfully the broad pompeii design is well proven over 100's of years and the variations you can see on this forum all seem to lead to happy wfo owners.

[adm]

Thanks Tony, that puts my mind at rest a bit!

The drawing doesn't include the external arch or flue parts yet - I'm still messing with those in SketchUp (which I am finding strangely addictive!). Also working on the base design....

Cheers,

Alasdair

[cannyfradock]

Alasdair

Your sketch-up design is also similar to my last build. Tony's comments are always spot on.....and lately have been a wealth of info to our newer members.

I pushed the entrance on my last build to 18" (as your diagram)...but I stayed with a 90cm internal diameter. Where I differed from your sketch is that for the internal arch, I used half bricks (cut with hammer and bolster) and positioned them back into my outlined circle to create a 18" opening. I turned the cut side of the brick into a point where the inside of the internal arch (upright) met the internal ring of the first ring (if that makes sense).

Another important point which Tony made is the arch/dome transition. You can't always keep a perfect circle on a Pompeii to make this transition , so sometimes you need to go a little "pear shaped"......or a slight oval circle to make dome and arch meet.

The back of the internal arch brickwork is cut to accomadate the 4th...or 5th? circle of the dome so as the dome circle is complete incorperating the internal arch . (when i order fire-bricks for a Pompeii build, I always order a few 1" fire-bricks which sometimes helps with the dome/internal arch transition.

Hope I haven't confused you with all that, but as Tony says....look at other builds to give yourself a better idea. Here's my last build..... ukwoodfiredovenforum.proboards.com/index.cgi?board=pompeiiovens&action=display&thread=1031

Terry

[faz]

With regards to entry width, have a think about how big your peel will be and how deep the entry will be, then whether that will give you enough angle to get to the sides of the oven with your peel. Make the door wide enough so your peel can reach most of the oven.

[cannyfradock]

Faz

A passing comment on your post......My first oven build was a complete guesstimate. I got nearly everything wrong. I thought that a 10" pizza was as big as I want so I made the width 1/ 1/2" bigger either side so I made the opening 13"......wrong!!. Through trial and error I now make each opening a minimum of 16" and push it to 18" on anything at least 90cm in diameter.

Terry