Pizza Oven build Mark II

[baldywills]

Hi All,

I haven't really been on this forum for a few years.. my bad! sorry.  My original build went well enough, well not bad for an accountant who usually does well in the garden rather than building something.

Anyway - I sold my house with pizza oven a couple of years ago and am now ready to start building the next one.  I don't think I will do it any bigger but I think I certainly learned some things I hope not to replicate this time around.

1. Have bought a table brick saw - last time around I was using a 9" angle grinder to cut bricks and it got a bit dicey sometimes with me nearly losing some toes.  This time I shall do it safer.

2. Am going to integrate the landing and chimney entrance into the dome so there is no separation between the two.

3. Am going to anchor the chimney better to the oven.  Last time the wind batter the chimney and the plate came away slightly from the brickwork.  I may even enclose the chimney in extended brickwork.

4. Last time the dome render did crack a little on the outside but these were not too bad, my problem with the brick work on the dome was my joints were not brilliant and could do better, hopefully the brick saw will help.

5. Last time I made the mistake of leaving my Calsil board outside before cutting and installing and it absolutely soaked up moisture. It was a very expensive mistake as I needed to get a new replacement board from Bristol.

6. need to make sure my base is dead flat and will probably make it thicker than last time which was around 10cm.

I have the opportunity to build an outdoor entertainment area next to a swimming pool so it is an exciting time for me.  Due to cost constraints I plan on building the oven first then adding on additional bits such as sink, BBQ and bar area.

So now I have shared my previous mistakes and the changes I have the chance of implementing I was wondering what given the chance other members of this forum would do differently with a second build?

Cheers.  Gary

[cobblerdave]

Gday
What size are you building. Sounds like you’ll need a larger oven with the pool and the entertainment area.
I think sometimes I built too big when I’m cooking a pizza for two in the kamado.
But the few times each year we have people over, it’s always a big hit. I’ve trained a few people up now to take over the pizza making duties so I’ve more time to enjoy the company of my guests.
Interested to watch you new build
Regards Dave

[downunderdave]

Jan 20, 2024 18:09:11 GMT baldywills said:

Hi All,

I haven't really been on this forum for a few years.. my bad! sorry.  My original build went well enough, well not bad for an accountant who usually does well in the garden rather than building something.

Anyway - I sold my house with pizza oven a couple of years ago and am now ready to start building the next one.  I don't think I will do it any bigger but I think I certainly learned some things I hope not to replicate this time around.

1. Have bought a table brick saw - last time around I was using a 9" angle grinder to cut bricks and it got a bit dicey sometimes with me nearly losing some toes.  This time I shall do it safer.

2. Am going to integrate the landing and chimney entrance into the dome so there is no separation between the two.

3. Am going to anchor the chimney better to the oven.  Last time the wind batter the chimney and the plate came away slightly from the brickwork.  I may even enclose the chimney in extended brickwork.

4. Last time the dome render did crack a little on the outside but these were not too bad, my problem with the brick work on the dome was my joints were not brilliant and could do better, hopefully the brick saw will help.

5. Last time I made the mistake of leaving my Calsil board outside before cutting and installing and it absolutely soaked up moisture. It was a very expensive mistake as I needed to get a new replacement board from Bristol.

6. need to make sure my base is dead flat and will probably make it thicker than last time which was around 10cm.

I have the opportunity to build an outdoor entertainment area next to a swimming pool so it is an exciting time for me.  Due to cost constraints I plan on building the oven first then adding on additional bits such as sink, BBQ and bar area.

So now I have shared my previous mistakes and the changes I have the chance of implementing I was wondering what given the chance other members of this forum would do differently with a second build?

Cheers.  Gary

Hi Gary,

some pointers on the points you've raised.

1. Good that you have a wet saw. Now be careful of your fingers.Dry cutting bricks with adiamond blade on an angle grinder produces a lot of dust even if the bricks have been soaked. The dust is dangerous for the operator family and neighbours to inhale.

2.Integrating the flue gallery and chimney into the dome creates a heat sink drawing heat away from the dome. This is why many builders create a gap there to stop heat travel by conduction.

4.There are two kinds of oven owners, those who say their ovens have cracks and those who lie about their ovens having cracks. It is the uneven heat creating a difference in thermal expansion that's usually the problem. If you have cracks in the outer shell they should be filled and sealed because they provide an entry for water which wets the insulation making it work very poorly as well as problems of it turning to steam crating a pressure build up. So they should be fixed.If you plan on having a roof over your oven its exterior is better left porous and breathable rather than waterproof.

5.All the cal oil board I've used that has got wet is restored to original condition with no loss of strength once dried. Not so millboard which just turn to mush.

6. You don't say how big you plan to make your oven which determines its weight, but 100 mm of steel reinforced concrete should be more than enough to support any oven. The reinforcing steel should be placed in the bottom 1/3 of the slab for maximum strength. The span between the support piers can be an important  design consideration. By cantilevering the supporting slab its thickness can be substantially reduced. The strength of a concrete slab is proportional to the square of its thickness. (a 2" slab is only 1/4 the strength of a 4" one).





 

[baldywills]

So have cleared the area and now filled in what was the gravel surrounding an old concrete pad with more concrete. The concrete has been poured below the current patio level so there is enough space to pave the area once the build is complete.

I have a friend who has a drone and he has supplied some ariel shots of the location - attached.

Sand, aggregate and blocks are turning up in a week so I can crack on with the base. I used hollow blocks which worked well for me and I plan on using them again. I need to get a shit load of rebar for when I form the concrete base for the oven floor.

I feel so much more at ease tackling this build - possibly because I have done it before but also because I do have more tools which I am sure I will use.

Last time I made my own Indispensable Tool, but is there anywhere that sells them?

[baldywills]

Feb 1, 2024 9:31:31 GMT downunderdave said:

Jan 20, 2024 18:09:11 GMT baldywills said:

Hi All,

I haven't really been on this forum for a few years.. my bad! sorry.  My original build went well enough, well not bad for an accountant who usually does well in the garden rather than building something.

Anyway - I sold my house with pizza oven a couple of years ago and am now ready to start building the next one.  I don't think I will do it any bigger but I think I certainly learned some things I hope not to replicate this time around.

1. Have bought a table brick saw - last time around I was using a 9" angle grinder to cut bricks and it got a bit dicey sometimes with me nearly losing some toes.  This time I shall do it safer.

2. Am going to integrate the landing and chimney entrance into the dome so there is no separation between the two.

3. Am going to anchor the chimney better to the oven.  Last time the wind batter the chimney and the plate came away slightly from the brickwork.  I may even enclose the chimney in extended brickwork.

4. Last time the dome render did crack a little on the outside but these were not too bad, my problem with the brick work on the dome was my joints were not brilliant and could do better, hopefully the brick saw will help.

5. Last time I made the mistake of leaving my Calsil board outside before cutting and installing and it absolutely soaked up moisture. It was a very expensive mistake as I needed to get a new replacement board from Bristol.

6. need to make sure my base is dead flat and will probably make it thicker than last time which was around 10cm.

I have the opportunity to build an outdoor entertainment area next to a swimming pool so it is an exciting time for me.  Due to cost constraints I plan on building the oven first then adding on additional bits such as sink, BBQ and bar area.

So now I have shared my previous mistakes and the changes I have the chance of implementing I was wondering what given the chance other members of this forum would do differently with a second build?

Cheers.  Gary

Hi Gary,

some pointers on the points you've raised.

1. Good that you have a wet saw. Now be careful of your fingers.Dry cutting bricks with adiamond blade on an angle grinder produces a lot of dust even if the bricks have been soaked. The dust is dangerous for the operator family and neighbours to inhale.

2.Integrating the flue gallery and chimney into the dome creates a heat sink drawing heat away from the dome. This is why many builders create a gap there to stop heat travel by conduction.

4.There are two kinds of oven owners, those who say their ovens have cracks and those who lie about their ovens having cracks. It is the uneven heat creating a difference in thermal expansion that's usually the problem. If you have cracks in the outer shell they should be filled and sealed because they provide an entry for water which wets the insulation making it work very poorly as well as problems of it turning to steam crating a pressure build up. So they should be fixed.If you plan on having a roof over your oven its exterior is better left porous and breathable rather than waterproof.

5.All the cal oil board I've used that has got wet is restored to original condition with no loss of strength once dried. Not so millboard which just turn to mush.

6. You don't say how big you plan to make your oven which determines its weight, but 100 mm of steel reinforced concrete should be more than enough to support any oven. The reinforcing steel should be placed in the bottom 1/3 of the slab for maximum strength. The span between the support piers can be an important  design consideration. By cantilevering the supporting slab its thickness can be substantially reduced. The strength of a concrete slab is proportional to the square of its thickness. (a 2" slab is only 1/4 the strength of a 4" one).


Cheers for the comment Dave,

 slab is deffo thick enough to support the oven and planned build, lol, my previous build did suffer from cracks on the dome which I sealed as they appeared (thankfully not many) but the biggest place for cracks was on the dome where it met the chimney. I could never seal it properly and I am sure the insulation was wet and kept blowing the seal when I fired up the oven - steam expanding I expect.

 So glad I have a wet brick saw as I did suffer with dust the last time.  not nice stuff! I also have a decent cement mixer this time around.

 Can't wait to start.

  Gary


 

[baldywills]

Have had my blocks delivered and dry laid them out in a couple of positions. Have decided to go with a corner location for the Pizza oven with a worktop area to the right and a BBQ to the right of that. The concrete slab has been laid and I can start work soon.

[baldywills]

Have decided on the layout and laid it all out dry.  Tomorrow I take it all apart and start to build it back up again.

The kitchen from left to right will be a work top, corner build 42" Pompeii oven, another work top and then a BBQ.  The worktops are going to be polished concrete which I have never done before but practised with a wet sander and many grinding pads.

The pizza oven is going to be a rendered igloo finish and is going to have more insulation than my previous oven. The whole kitchen is going to be faced with reclaimed local bricks and I will put a roof structure over the top of it all measuring 6 x 5 meters.

Well that's the plan anyway.

[downunderdave]

Hi Gary,

If you plan on polishing your concrete countertop you will need an appropriate machine. I have a small 100mm diameter machine with removable polishing discs that has a water feed in the centre. This is ideal for small jobs, although really messy, but for large ares as you propose you will need a larger machine. The small one is unable to keep the surface perfectly flat as it digs in more. The dust is quite dangerous so generally a water fed machine is the solution, but on doing a large job and finding my small polisher inadequate I went out and hired a larger machine. It was a Hilti polisher and instead of having a wet feed it had a heavy duty vacuum attachment that sucked all the dust up. I was skeptical but it turned out to be an amazing machine perfectly suited for the job, although expensive to hire.

Concerning you issue about cracks around where the outer igloo meets the flue pipe, this is a common problem and I've seen many ovens with water entry at that point. Because at this part of the dome it is horizontal and water hitting the side of the pipe runs down to acumulate around the base of the pipe it creates an ideal entry point for rain to enter the insulation space. The problem is exacerbated by the much more conductive stainless pipe expanding against the render surrounding it. Heat transfer to the cement render also creates its own thermal expansion issues where its hotter than the render thats a bit further away.I have a solution that works extremely wel. If some corrugated cardboard is wrapped around the pipe then thin plastic wrapped around the cardboard, The cement render can be worked up to it. Then when dried and cured the cardboard can be removed easily, leaving a gap of around 5mm or so which can then be filled with high temperature silicone,At this point on the oven the silicone is adequate although you do need to be careful not to allow flame up the flue pipe or you'll overcook the silicone.

Hope this helps,
Dave

[baldywills]

Cheers Dave,

great advice.  I shall do it and see how I get on.

Eventually I shall get a roof over the kitchen thus eliminated the problem but until then at least there will be a good seal.

Love the worktop btw.  Am hoping mine will run out that way.  I do have the wet grinder/polisher which I have already practised with - mixed results so far.  I embedded some marbles and bits of aggregate in some concrete and polished it up fairly well.  

I think it will be mind numbingly tedious to do the whole of the worktop space but my main worry is what I am going to seal it with.  I have some stuff I bought a couple of years ago in the shed but I will have to go and read the directions again. 

Just need some decent weather so I can get back outside.


All the best
Gary

[downunderdave]

When you build the formwork you will need to also place some temporary timber props in addition to the block piers. Make sure to cover the layed up concrete with plastic once it has set. Keep it covered for at least a week to enhance its strength. These pics may help.

[baldywills]

A bit of copy and paste from the Forno Bravo Site

Hi All,

Thought I would commit my build into a thread with pics. This is my second build so hoping to do it quicker and better than my last one which went ok. Certainly making some major changes to the way I am setting up the oven, mainly because I have more space and resources this time around.

The setting is a pool area which had a bit of unused land at one end full of gravel (next to a pool, why would you?) so I have laid a concrete base over the whole area with a view to it being paved but with the obvious addition of an outdoor oven, BBQ and bar. All of this to be covered, due to the nature of the British Weather, by a roof.

The pizza oven will be a 42" Pompeii corner build with polished concrete worktop to the left and to the right with a sink fitted to the right hand worktop. To the right of that will be a BBQ. The blockwork will be covered with reclaimed local Torquay red brick to give it an 'aged' look.

The slab is 10cm thick and as I have a surplus of calsil board I will ensure I use enough under the oven floor bricks. Thankfully I have a huge petrol powered water-cooled brick saw for when I get going on the brick work. Last time out I used a 9" angle grinder to cut all of the bricks and I am grateful not to have had any accidents with it! I figured with the large brick saw (which cost £450 plus I had to drive an 8 hour round trip to collect) it was worth it for safety reasons, and also I am 100% sure I can sell it at the end of my build for the same as what I paid for it. Quids in!!

I plan on polishing the concrete worktops but have also seeded them with different coloured glass particles. This is new to me but I did some trials with the process a few years ago and having bought all of the kit it is about time I used it in anger.

I have just finished the concrete pour so now I can take stock, tidy the area and prep the next stage which will mainly be brick based and post some pictures on this and the UK site.

So far I am very happy with the progress and how it's looking. I am particularly happy with how my formwork ended up as my previous build was a bit crap and very Heath Robinson.

Cheers. Gary

[downunderdave]

Hi Gary,

See my (ad free) response to your project progress on the Forno Bravo forum.

Cheers,
Dave

[baldywills]

[baldywills]

Cleared the crap out of the way so I can see what space I have to put a bar in.

[baldywills]

Hi Dave, cheers for the info in this post and the last, 

Can I ask how long you left the concrete before sanding and polishing it?  I think it looks like a very boring task and I think I would rather leave it for a bit and maybe do it in-between brick work or if the weather is a bit wet.

I looked up a Hilti grinder and they look quite robust but look more like grinders,  Would you be able to describe what process you went through for polishing the worktop?

Cheers

Gary

Apr 2, 2024 19:52:10 GMT downunderdave said:

When you build the formwork you will need to also place some temporary timber props in addition to the block piers. Make sure to cover the layed up concrete with plastic once it has set. Keep it covered for at least a week to enhance its strength. These pics may help.