From Mailbox to Pompeii in Colorado

[DrakeRemoray]

Hello All,

First, I have had a love/hate relationship with these webpages/forums over the last couple of days.

After baking some really good bread from Nancy Silverton's La Brea Bakery cookbook (all natural self made starters), I got really interested in the idea of a bread oven. I have been reading about and planning an Alan Scott style oven off and on for 3 years (I purchased the plans and everything). I finally concinved my wife that this was a good idea after paying a landscape architect to draw the attached picture for me. I live in a convenant controlled community and I submitted plans to my HOA last week and I am waiting on approval now. (I am sure they are saying, here comes the guy with the big playhouse and the pond, what does he want now?).

So here I am reading and drawing and planning like crazy and I find this site. Arrrggghhh, my mailbox oven plan will not really meet my desires, I say!! I have to start my internal oven design over? I swear I could draw and build the Alan Scott oven from memory I have studied it so much. This new dome oven idea made my head hurt…(that was the hate part)

After a couple of days of reading and fretting, I have determined that the dome is the best design for me. I am more of a cook than a baker, and I like to entertain more that I want to bake massive loads of bread.

So now comes the love…I love the idea of an oven that heats up faster and gets a nice hot 2 minute pizza heat! I love the idea of a larger door to make the oven easier to work and even more entertaining. I love all of the activity on this forum!

I am reworking my plans and I do have some questions.

1) I am trying to determine what the outer diameter of the dome will be. My understanding is that the walls will be 4 inches think, but how thick is the blanket and how think should the perlite concrete mix be? I am also planning on building square housing/exterior walls around the insulated dome and I plan to put loose vermiculite/perlite in void.

2) Has anyone built the "Island" hearth? It looks pretty complicated, but does seem to have it's advantages. Is there consensus on the benefits of this style? If most people are using the standard insluting slab below a reinforced concrete slab, is there any problem with the slab heating all the way to the edge and thereby heating up my (planned) rectangular enclosrue walls?

3) I have read that some (all? Most?) ovens crack. Will a lot of smoke get into my enclosure? How many people experience cracking? What is the best way to mitigate this risk?

I am sure I will have many more questions, but thanks in advance!

DrakeRemoray

[arevalo53anos]

Drake:

Answering question 1)

Pictures could give you a better answer that lots of words.
The oven in the pics is 40' internal diameter, 41/2' sided bricks wall, 1/2' cladding, fiberglass and 2 1/2' vermiculite/cement isolation.
Pics in annex.

Luis

[arevalo53anos]

Drake:

Answering question 2.

I do not think that could be complicated. Worth the work. And there are not energy wasted.
Pics in annex

[arevalo53anos]

Drake:

Answering question 3

There will be always cracking.
No matter between certain limits.
There are a lot of solutions in this forum to mitigate this problem.
Was not a big deal for me.
See pics in annex

And welcome to this forum and good luck with your new passion (it will be)

Luis

[james]

Drake,

I think Luis comments are right on the mark. Here's a couple more things to add:

1. For the enclosure dimensions, you roughly have the following:

42" floor
8" walls (4" each side)
2" insulfrax (1" each)
8" vermiculite loose (4" each)

That means 60", plus the thickness of your upper walls.

2. The Island hearth is nice, but not necessary. I've done it, and it does take more time and planning. You can either install vermiculite layer under the concrete layer, or the vermiculite layer on top. The more of these we install, the more I am coming to believe that the vermiculite layer should go on top. The oven floor is more responsive, and still holds enough heat for baking and bread.

3. The vent area on both of my letterbox ovens had cracks that let out hot air and smoke -- which I sealed. If it makes you concerned, you can always buy a Casa insert. They don't crack.

I would also add that you don't have to tell anyone about the change -- at least not anyone who won't cook in the oven. From the outside, it will be exactly the same, so the CC&R group shouldn't know or care about the difference.

There is a good cliche that I am looking for, that basically says better earlier than later. You will enjoy your Italian brick oven much more than you would a bread oven. It'll be great.
James

[DrakeRemoray]

Thanks guys.

James you are right about it being better to find this out early!!

James are you saying that the hearth bricks should rest directly on the vermiculite concrete insulating layer? Does that give enough mass? How about laying them on the insulating layer but turning the heath bricks on their 4 1/2 inch side? That may give it a little more mass?? Opinions?

Another question. A builder friend of mine suggest we skip the slab and the concrete blocks and just build forms and pour the whole stand including a structural slab of concrete across the top of the stand. Then we would pour the insulating slab on top of that. Any thoughts on that?

[james]

Buongiorno Drake,

I think you can set the floor bricks on their flat side, directly on the insulating layer. You can put the bricks on their ends, but at that point your floor would be thicker than a commercial oven baking pizza in Italy right now. Still, if you are leaning toward bread and baking, it would definitely work.

I think you will save time and $ if you just dry stack you blocks. They cost $1.09 at Home Depot and you can dry stack them. The stand really just flies up.

Keep the questions coming.
James

[jengineer]

Drake in Littleton Colorado, has a question regarding the foundation. I am excerpting part of our conversation below....

----------------------
I spent 10 years, high schools and college, in Lakewood and Denver

Due to your ground conditions you may want to consider using a more substantial foundation. I rememebr both our driveways had upheaval problems each winter/spring...

I sent him the link from Ontario Jim about his foundation (essentially a 10 inch thick table that is sunk to grade).
------------------------------------
His response -
I do have those expansive clay soils. I am considering pouring walls to a depth of 1ft below grade and skipping the slab altogether. This instead of a big slab which will always crack in Colorado and stacked cinderblock walls, and then pouring a top slab. I would pour the top slab (deck) at the same time as the walls, this would cut the build time by at least 1 weekend.

Any thoughts on that?
---------------------------------
Yes it has snowed in June in Denver. If I understand Andrew correctly the foundation will be a footing similar to that of a house bukilt up to the height needed for the waist high deck. No slab on the ground.

patrick

[CanuckJim]

Pouring walls below grade is a good solution, but I'd go deeper. Consider sono tubes inside the walls as well. Sounds like we have similar soil considerations.

Jim

[DrakeRemoray]

I dug a big hole this weekend. I ended up renting a mini-excavator to both make sure I got it done this weekend and to save my back. We have really heavy clay soil.

The excavator also allowed me to go deeper. I am now planning on putting sonotubes in the four corners.

I am now planning on having the wall be 4 feet tall with 1 foot below grade and then sonotube foundations another 2 feet below that. Probably overkill, but with these expansive soils...

I then plan to backfill the center part of the stand and put some pave stone in there instead of any kind of flatwork. I think it will go nicely with the overall oven.

I WAS planning on pouring the top slab of the stand at the same time that I pour the walls and making it one monolithic stucture, but another engineer friend suggested that the top slab would have more lateral movement due to themal expansion and it might push and pull the walls. I guess this explains the slip plane made of aluminum flashing shown in the plans...Now I think I will pour the walls first and then pour the top slab.

Again, comments and suggestions are welcome!