Just joined and plan to build oven

[Chris/trev]

Hi all
Chris from Toowoomba Qld have been discussing building a oven for a while and now the time has come .I picked up a oven templates ,vermiculite insulation o and jigs etc off gum tree. I plan to use bricks from Warwick brick works (2nds) on a besser block stand

[oasiscdm]

Re: Just joined and plan to build oven

Welcome Chris/Trev

Its great to have you on board. You have come to the right place and I have found fornobravo an absolute brilliant resource.

When you need to get an answer someone will come too your aid.

All the best.

[cobblerdave]

Re: Just joined and plan to build oven

Hi all
Chris from Toowoomba Qld have been discussing building a oven for a while and now the time has come .I picked up a oven templates ,vermiculite insulation o and jigs etc off gum tree. I plan to use bricks from Warwick brick works (2nds) on a besser block stand

Gudday Chris
And welcome. So your going to use those Warwick monsters ... They are the stuff of legends ... Reputed to weigh more than a Dinmore firebrick. On the coast it's to close to Dinmore firebrick so to date I have never seen someone use them on this forum thus far. Post heels of pics I'm watching your build with interest
Regards dave

[Chris/trev]

Re: Just joined and plan to build oven

Thanks guy's
I hope the Warwick bricks are the best way to go .Has anyone used these and does the weight of the brick indicate better quality .My first step is the base so weather permitting I will start this weekend and clean out the site and get ready to poor slab.Concreter mate said best poor a slab about 8-10 inches thick to eliminate movement later on .So I will be mixing for a while .with the base of the oven I plan to do a suspended slab on top of besser brick frame with approx 5'' slab with 3'' of this normal concrete then top 2'' use mixture of vermiculite and portland cement .Some one questioned putting mesh in this slab as steel will heat and expand and cause concrete to crack any ideas?
Also once I get the dome finished do I use insultion blanket 1'' or better using 2'' thick blanket ?
The way I read it I then cover the blanket with chicken wire and then use same mixture of vermiculite and portland cement to insulate ?
Am I on the right track
To many questions ha
Chris

[UtahBeehiver]

Re: Just joined and plan to build oven

Welcome to the wfo world. Great bunch here. That is a massive base slab. Not going anywhere. Are you going to add any other type of insulation over the 2" of vcrete? You may want to consider more vcrete or add CaSi board on top. 2" vcrete on floor not enough. Interested to see these jumbo bricks.

[Greenman]

Re: Just joined and plan to build oven

Hey Chris

Welcome to WFO land. A job worth the doing and a tasty end result. If you can not find what you need to know here then someone will come up with advice soon enough.

I was going to use Warwick bricks before I found a source of cheap firebricks. The Warwick bricks are not firebricks but will do the job and if you can get them right will cost you about 25% of the Dinmore firebricks.

Not sure why you would need such a thick slab, if 100mm of well reinforced concrete 'moves' then 200mm will move too. If ground movement is an issue then other structural strategies are needed. There is plenty of weight to hold it down and that weight is evenly distributed so if your foundation is firm you should be right.

With the hearth slab I put a 100mm reinforced concrete slab on the besser blocks and then boxed it up another 100mm and formed the keyhole shape for the oven and entrance, poured around that and then filled the keyhole shape with vermicrete. The steel in the slab is not an issue but you don't want steel in the vermicrete under the dome and entrance.

With the ceramic fibre blanket, the more you use the less vermicrete you need. If you use 1" of blanket and 3" of vermicrete you will be safe or 2" of blanket and 1" of vermicrete will give much the same result. More is better regardless which way you do it, no such thing as too much insulation.

All the best with your build, like I said, it is a job worth the doing.

[Chris/trev]

Re: Just joined and plan to build oven

Thanks for the advise Greenman
I like your idea about the hearth slab just doing the keyhole as insulated that sounds like aplan .I have been thinking about the base slab and is probably over kill so will just do a thicknessing beam around the edges and 100mm for the rest .
Have found some new secondhand Warwick bricks in Toowoomba but old mate has over 600 first grade and wants $400 or I can buy the seconds from Warwick for about 66 cents each .To my counting I need about 300-350 bricks for the job so will work out which way to go .
I am impressede with the advise that I have recieved in such a short time

Chris

[Greenman]

Re: Just joined and plan to build oven

Hey Chris - Those bricks are good buying. The same bricks here in Bundy are $2 each (very expensive freight here). That makes both sources of bricks the same @ .66c. The Dinmore fire bricks are about $4 each depending where you get them.

Here is a pic of the formwork for the keyhole.

[Chris/trev]

Re: Just joined and plan to build oven

Greenman
Thanks for the info and photo's What size over is yours and is it big enough .Have been chasing up info on insulation blanket and contacted company in SA .They have come back with Brissy office .They can supply blanket and also have a motar mix to use for constuction .Not sure if need to go to that extreme but sold in 20 l buckets at $55 .They suspect 1 bucket covers 100 bricks .I feel that this product be great for a kiln etc but over kill for pizza oven what did you use on yours .
I am luck with the brick price and will try to do deal with the 600 guy
I grew up in Childers just down the road from you still have family up that way
Chris

[Greenman]

Re: Just joined and plan to build oven

Chris

My oven is 36" and is big enough for me. I can cook a couple of pizzas at a time easily and there is plenty of room for roasting etc. I got my blanket from Total Refractory Management at Springwood. One box did almost 2 layers and I put vermicrete over that.

I used home brew mortar, it is cheaper and worked fine. I used one bag of fireclay and that was $28 then there was lime, portland cement and sand. It is fairly forgiving and I suspect that once the dome is complete it matters little what is bonding it as it would hold ok provided the joints were reasonable. You landed on your feet with the bricks.

I have only been in Bundy for a couple of years. Its a good spot. A bit of fishing and crabbing and it is just like a big country town.

[david s]

Re: Just joined and plan to build oven

Hey Chris - Those bricks are good buying. The same bricks here in Bundy are $2 each (very expensive freight here). That makes both sources of bricks the same @ .66c. The Dinmore fire bricks are about $4 each depending where you get them.

Here is a pic of the formwork for the keyhole.

If doing a recess like this you should drill some drain holes in the bottom just in case water gets in and sits there. The holes will also allow moisture in the vermicrete to evaporate. I cover them with fibreglass insect screen from the top side, so to vermicrete doesn't fall through and hornets don't plug them up.

[Chris/trev]

Re: Just joined and plan to build oven

I am building a 42'' oven and just working out the foundation slab size if take into account that oven is 42'' inside , then 4.5'' brick x2 ,insulation blanket is another 2'' then vermiculite mix is 8'' all up the 2'' exterior wall plastering come up to approx 63'' outside of dome give or take 2''
If construct oven slab 1800 wide x 2000 deep will that be big enough?
and
Looking at foundation slab approx 2000wide x 2400 deep?(prefer smaller)

Then would build with 4 besser across back (1560mm) and 4.5 (1755mm)down the sides (using the back bric as my half) and top slab will have a slight overhang on all edges
Am I on the right track?
Chris

[cobblerdave]

Re: Just joined and plan to build oven

Gudday
If you are going to build your foundation slab bigger than your stand perhaps consider including another water resistant layer at the first cement block.
Regards dave

[Chris/trev]

Re: Just joined and plan to build oven

Well the job has started .I found some besser blocks on Gum Tree so the base is ready to build just need to prep and pour the slab maybe Saturday.Then yesterday travellled to Warwick and purchased my bricks for the build.
Wayne at warwick brick works was very helpful with oven ideas and I even got some fire clay as well.So it finished up being a worth while trip .

For my suspended slab was wondering if it is a concern if leave the formwork in place for ever .Just the rear section of base will be closed off completely ,I plan to have front section open for wood storage and build a strenghting wall to split base into 2
If i used ply it will stay inside till it rots or should I use fibro sheeting ?

Chris

[cobblerdave]

Re: Just joined and plan to build oven

Gudday
Sorry edited out this post ......didn't read your post well enough
Regards dave