Oven in existing brick outbuilding

[Wlodek]

Dear All,

As I have been worrying about a suitable place for the oven, my genius wife activated her lateral thinking and suggested that I simply build it into the garden store.

The store is a brick building with slate apex roof and is ideally located. It is quite wide, but internally it only has 140cm depth. I can break out through the wall to create a suitable landing and chimney just in the right place.

I attach a Google Sketch-it rough sketch, not showing the actual oven in the shed, only just to ask my question better.

I think I can fit in a slightly elliptic oven inside, the shed would provide a sheltered wood store. The oven would have brick walls filled with perlite and no roof except for the shed roof.

There would be no problem with the chimney going through the roof as it would be all outside.

What do you think?

W.

[DrakeRemoray]

Re: Oven in existing brick outbuilding

Looks like a great idea! Some things to thing about:
Chimney would need to be 2' taller than any roof within 10' of it. Of course that is US building code...yours, I am sure, would be metric
You should take a good look a Dmun's build, as his is sticking into his workshop. Great work on the google sketch it!

Drake

[Wlodek]

Re: Oven in existing brick outbuilding

Thanks Drake.

Both for encouragement and for the pointers both to Dmun's design and to the Building Regs. It is 2.3m here (7' 9"), I have just checked, and I can keep that distance, I'll just make the "shelf" stick out a bit more.

My work with Sketch-it is rather rough, OK for the very first attempt of someone who never used a CAD before, but that's it. There are some odd lines across, walls with zero thickness etc., but gives the idea. I'll work on this. I need to work out how to draw a dome now!

All the best,

W.

[Wlodek]

Re: Oven in existing brick outbuilding

Possibly bad news. In order to stick to the 2.3m the oven "landing" has to be nearly 1m deep. Either that or I would need to modify the shed roof a bit to accommodate the oven dome sticking out through the wall.

Question: Is a 1m deep landing a bad thing? Apart from needing longer handles on tools (2m!)

Also, I am very grateful to Dmun for the Sketch-up pointer. Makes the design/planning process so much easier even at the basic level.

Cheers,

W.

[maver]

Re: Oven in existing brick outbuilding

If you look closely at Dmum(David)'s work he modified his wall so that the dome protrudes, then build a brick wall partly outside his shed and the chimney through that new outside brick wall. When you say 1m landing, do you mean 1m outside the dome or first a vent space and then another 1m in front of that? Would angling the flu (up to 30 degrees) for part of the chimney run solve your problem? If you use stainless flu pipe you have some options regarding chimney angle.

[Wlodek]

Re: Oven in existing brick outbuilding

Thanks for this M.,

Sorry about being vague. 1m from dome opening to the edge of the landing, including the vent space. Sort of like in the attached cross-section jpg. Looks silly ... The garage is adjacent to the shed on the right and is quite high.

Also, silly me, can't find David's photos you mention. Just looking through his posts would take ages. Could you point me towards some, please?

I suspect that sloping flue might look odd in this setup, unless it is sloping inside some "square" brickwork. Which is an idea. I'll try to sketch this and report.

Thanks a lot,

W.

[dmun]

Re: Oven in existing brick outbuilding

Wow. I'd second maver's suggestion that a taller chimney might be a better solution that building it that far out.

Here's a pic of what I did:



From this page:
I built my dome halfway in the "shed". This involved more demolition that you are proposing, but the news is that the first brick you bust out is the hardest.

I'd be concerned by how far the chimney is from the dome. It might work fine, but you'd be in uncharted waters.

I'm glad you're finding a use for sketch-up. It's very powerful from what little i've used it. CAD programs are like languages. Everyone thinks theirs is the best, and no one can understand anyone else's.

[Wlodek]

Re: Oven in existing brick outbuilding

D'uh! I have looked at your geodesic dome (in awe), but its main feature distracted me from what I was looking for ...

Thanks. The good thing with the demolition here is that it is only a small lean-to apex shed, so even in the worst case the damage will be limited. Also, the roof construction is very light, so I won't need pillars.

I am trying to work-out and visualise (with Sketch-up) how much I have to stick the dome out to comply with Building Regs. It will be also useful because the back of the shed won't be cut-off and I can dry my wood there (and have a good warm den too).

Best wishes,

W.

[DrakeRemoray]

Re: Oven in existing brick outbuilding

You could not have such a large landing, I think it would be impossible to load and operate the oven...

[Wlodek]

Re: Oven in existing brick outbuilding

Right,

Played with Google Sketch-up and it looks feasible. Oven is half hidden in the shed but with no shed roof changes, just the wall. This now complies with Building Regs (I believe).

Minuses I can see:

• the cooking surface is low, but then I wanted it to be visible from sitting position - the oven is in a covered sitting area - a useful sort of fireplace, where you can see tasty things not just embers.
• the passage between the oven and the raised flower-bed/planter is narrow - can be sorted out
• anything else?

In the attached you have a "finished" version, with shed wall taken out for clarity and the sides of the insulating enclosure not included inside the shed - they will be there and filled with perlite too. You will also see the "naked oven" version, for interest. I have downloaded a sensible pizza oven component model from Google Sketch-up site and edited it quite a bit.

Does this look sensible now?

Best wishes,

W.

[DrakeRemoray]

Re: Oven in existing brick outbuilding

Looks good...the only odd thing I see, and it might just be the limit of google sketch, is that the chimney is generally right over the opening. Not sure why you would build a big collar out in front of the vent/chimney...if you have the space, just make it open landing area (to rest a pizza or a beer...)

Also, how low is low? I might mock up that height and door size in real life and try leaning over and putting a pizza in to see how you would feel about it.

Drake

[dmun]

Re: Oven in existing brick outbuilding

I designed the height of my oven floor so that it was exactly at eye level when seated at the dinner table. That's 43" from the ground. There's no set rule about the height of the oven, except that you don't want to cook pizza on your knees.

That flared opening is a design feature? It might be more useful to have it open, and counter/workspace there. There's nothing wrong with doing it that way if you like the way it looks.

One little consideration - if your shed roof has a wood structure, there needs to be at least two inches of clear space between the oven and the sill plate. There's no real hazard - a full fired oven with proper insulation is only warm to the touch, but code calls for two inch clearance to combustibles.

[Archena]

Re: Oven in existing brick outbuilding

How tall are you? Seriously, if you put it at average eye level and you're fairly tall you'll be spending a lot on the chiropractor. The real world mock up is a good idea. I'm 5'4" and if I'm judging correctly from the diagram I'd find that an uncomfortable height to work at. (Never used a wood fired oven, yet, but I've done more than my fair share of baking - regular ovens are too low in my opinion.) It'd be okay for something I was going to leave in for a while, but things moving in and out fast would be a royal pain - literally.

Your back will probably like it higher. If you're mostly going to cook a few things then sit around looking at it then it won't matter so much. If you plan on doing any heavy duty cooking, however, I think your back will like you better if you bring it up to a counter height.

Conversely, you could just resurface the floor to bring it up to where those sitting at the table on the platform could see in whereas the cook would be standing on the ground level and have it at a good cooking height.

[Wlodek]

Re: Oven in existing brick outbuilding

Thanks for the feedback.

The flared, shielded opening was I guess my response to the recent weather here, which of course the Californians won't even want to know about. But then, since it is all under a gazebo of sorts I'll just remove this "feature".

Smoke chamber with chimney close to the dome opening seemed natural. I did not include the dome door in the sketch as I used a "ready-made" Google library oven bit for this sketch. It will be there, just as in the Pompeii plans, which I don't intend to change. My main intention in this thread (which, being myself, I did not state clearly) was positioning the oven using the existing shed.

Height is clearly an issue. Originally I wanted the working surface level such that I could see to the end of the oven without bending, and I am 6ft (182cm) tall. The presented "design" height was dictated by leaving the shed roof intact. I think you are right, and even though I do yoga, mixing it with cooking might be the wrong idea.

It looks like the shed is going. At least partly. Unless someone has an alternative idea. Like lifting the central part of the roof (providing more space between the insulation and the rafters too).

It is great to have some experienced, critical help ... thanks.

Best wishes,

W.
(in a very very wet Lake District smelling like Autumn already)

P.S. If anybody wants to use the Sketchup files for their own purposes I can upload them somewhere when I have corrected them a bit. They are not perfect, but they may be useful. Just let me know.

[dmun]

Re: Oven in existing brick outbuilding

Most shed roofs are nothing to brag about. In addition, yours is sloped to dump water on top of your oven, and into your bake house area. Here's my suggestion. Loose the shed roof, and extend the roof of your bake house to the end wall of your garage. For one thing, it will make the bakehouse roof much more stable to have the end rafter assembly bolted to the garage wall, and also, the entire work area and the oven will be more waterproof. You could then extend your shed walls upward to the new rafter line with the same brick you are using for your oven housing.

Just remember, the rafter structure has to be framed two inches from the outside of the masonry chimney. The gap is covered with flashing, which is a little beyond the scope of this reply. If you are using a commercial chimney unit, it will have it's own clearance requirements, but it will be self flashing.

I've drawn a couple of lines on top of your .jpg, to suggest what I'm talking about.