refactory castable cement

This is totally off subject but I just know someone will find this link and go WOW !!!! thats what i was looking for.

http://www.darleyrefractories.com.au/castable-use.html

the website explains heaps about castable cement and who what why when and how...

9 steps to finishing the oven

Just 9 more work days till the oven is finished and I thought i'd detail the end process here.

You really need to read the previous post first to have this one make sense. these steps will also be expanded on in coming posts with images.

day 1) cut the "drop" bricks to size, what i will be doing is cutting there edges so they fit properly on an angle and create a good seal. Create a small arch template, this is for the small 1/3rd bricks on the side. Fondue "drop" bricks into place with last of the front of oven bricks using the "L" metal to hold the bricks over the oven door. Cover the whole section in fondue to make a good seal.

day 2) Clean up the inside of the drop with angle grinder and remortar any holes. (see previous post of the dome clean-up)

day 3) Mortar/build chimney section including part that overlaps the "drop" . build the dome sides wall wooden borders that will hold the concrete/fondue mix that will hold the sides together and insulating and provide a nice even outside surface to render. Place the insulating wool and chicken wire over the dome and drop ready for the concrete/fondue mix ( I may be adding vermiculite in that mix as well.

day4/5) this will be a LONG day, fill the sides with concrete/fondue covering the wool UP TO when the dome stops being vertical and starts its arch section THEN sitch to a concrete/fondue/vermiculite and clay mix to cover the dome top. There are 2 reasons for this change in mix, the first is I want the sides to be SOLID and the weight of whatever i put on top will natutally push the dome sides OUT, the second it that heat rises so most of the heat and thus insulating should be at the top of the oven, thus the vermiculite and clay, the clay is simply because its good to use but also I have ample supply in the backyard so why not use it !!

This will seal the entire oven back to front up until the chimney begins, my chimney is a decorative OLD chipped brick so i want it to be seen.

day 6) remove the wood holding the concrete together and hope it all worked ! complete the top of the chimney with the flue going through the roof of the outdoor area ensuring the smoke escapes. hopefully my front pavers will arrive by then and i will create the front paver "level" so i can set them.

day 7) Lay the front pavers, I need to let them set so this will be an easy day, I will then build the front arch another day as I really need the pavers to be solid as a rock, but i have other small projects to do so no big deal.

day 8) build front arch, as i am doing a double brick side which will be very stable I shouldn't have a problem with the dome weight but it would be better to wait after building the vertical before doing the dome.

day 9 ) add extra vermicullite/clay mix to top of oven if I feel it needs it. by the time i get here i would have done some firerings of the oven and would have got it to a good temperature so it will depend on how hot the oven gets.

During this whole process I will also be creating the oven door and tools to use in the oven, more on that later.

The oven drop

How to do an oven drop.

everything i'll write about here relates to this starting image.

So what you see here is the dome and front bricks to close off the oven, that thin piece of metal marked by the red arrow is going to be placed from the oven to the front arch to stabilise the structure forward of the oven, from back to front it goes oven then chimney section then front arch, they do not intertwin much so placing a rod across them all it will give strenght.

The metal rods around the dome area marked by the lime green arrow, are there until I do the side walls reinforcing, they presently are not doign anything as the dome is solid by itself but they did help until the mortar had set, i'm just keeping them there to make myself feel better !

The front area marked by the blue arrow is where the front terracotta pavers and cream front arch will be built, the pavers haven't arrived yet and they are not going to be "brick height" so i will need to "build that area up" , i have a few options but haven't decided yet, i think but i will lay a small slab to the correct height.

The area marked by the orange arrow is where the chimney bricks will go, they are located outside of the oven dome ....after the "drop" and before the front arch, the plan is that the drop will force the smoke down and out of the oven and the chimney will suck the smoke up so NO msoke reaches the front cream arch and it remains clean !! big hope? we'll see.

The lightblue/aqua arrow is a bit difficult to see what i mean but it is where the drop starts, but it is actually going to be a third of a brick wide with a full brick infront of it, it will then be an arch 1/3rd of the way into the centre that reaches the full drop bricks. HARD to explain but I intend to fully detail the process with images as i go as it has taken me loads of time to work it out as there is little quality info online i can find.

The thin yellow horizontal line will be a metal "L" bar to rest the bricks on, the squiggly angled yellow lines represent the slanted brick "drop".

Next post I will detail the steps I will take to complete the oven.

Another before and after/now

Just thought i'd show you the progression

this is way back in March 2009


Here we are at December 2009, remembering that its only been a lazy sunday project its really starting to show some promise, The white rods you see is a temp structure so i can sling a tarp up on hot or rainy days.
The stack of bricks at the back are for the next stage which is the smoker oven and "4 burner bbq" area which will be where the red trolley is in this image.

The blue tarp is covering the buffet/herb area, you'll see what i mean once its finished and its looking great, i'll do a seperate post on that alone once completed.

Dome bricks cleaned

The next week I reground the filled mortar and its as hard as a brick which is GREAT.



It looks fantastic , I am doing the front "drop" section this week and that will complete the oven internally, this time I will be using heaps of mortar to make sure there are no gaps and then simply angle-grind them flat later.

The drop section is trick as its hard to get the bricks all lined up. I'll explain that next post.

Arch gaps, fixing the holes

In the last post i described i ended up with gaps in the bricks of the arch, in this post you will find out what i did about it.

Firstly I used an angle grinder to remove any loose mortar and excess mortar so I had a flat arch interior surface, I also used a chisel and hammer to dislodge alot before grinding and also to scrap the small mortar off the bricks, thats the thin "wash" that happens.

I angle ground into the gaps as well tho make sure anything loose was fully removed. most of the gaps were only a few cms deep but 1 was almost a full brick deep !! so i don't know how that occured?

So now i have a clean area to refill, please note the obvious.... I haven't done any burning of the interior yet.

So i now mixed a small amount of "fondue" and started at the back of the oven systematically filling in the gaps, i used a thin pointed tip trowl and a fatter round tipped trowl for the big holes. For the small gaps it was easy to just push some mortar into then using the pointed trowl for the larger gaps i used the rounded trowel and HEAPED it with mortar and pushed it into the gaps, and again and again and again to make sure it was filled up, THEN i pushed my finger into the gap to push the mortar in and you'll be surprised that the mortar does move in, THEN once again trowl pushed more mortar again and again.

The theory is that if you leave a gap (air pocket) that that can expand and explode/damage your oven THUS my now reasoning that its better to make sure your mortar is complete and angle grind it off later.

Having said all that I have seen MANY oven insides that the maker hasn't bother bout it and is using it successfully so this is purly my opinion.

This whole process to took me 7 hours ! (just so you know there is 33 bricks in my arch, [ 3 rows of 11] just so you can calculate it to your dimension)
THEN, yes its not finished yet, then i let the mortar filling set a little and THEN went back in and with a scraper, scrower and sponge scraped the excess mortar off then scrowed then sponged to end up with a clean smooth fully mortared internal surface. This took me another hour+

I will now let it dry for a week and then do some (very little) cosmetic work on the inside with a chisel and angle grinder.

SOOOOOO, In conclusion you can see that perhaps making sure all joints are fully mortared is much better then trying to do "mortarless" joints.

DISCLAIMER: my bricks are square thus i of course have to have gaps, if you are using tailored angled bricks then i haven't a clue wats best, but i do think if you are using ANY mortar at all then making sure it reaches the inside is vital in my opinion.

The whole day was full on and i finished in darkness so now photo on this post but it does look GREAT, I'll put a photo of the end result into the next post next week.

Arch interior

Once I let the arch dry for a week i removed the template and it stands up !! yippee
I had covered the template with paper so the mortar didn't stick to the wood, thus i have patches of mortar and paper at the joins in the arch

Here's a close up, you can see here we have 2 different situations, 1 is that the joint is filled and has excess the other is there is a gap where no mortar got all the way down.

At this moment I don't have an opinion on which situation is best, all I can tell you is what i did next.

yesterday i crawled into the dome on my back with gloves, googles, mask, spotlight and angle grinder and started to remove the excess. It was a VERY awkward and duty job. The result was the places where the mortar didn't go all the way to the botom of the brick and there was a gap.. THAT mortar was brittle? so I had to grind it back a bit INSIDE the joint to get to firm mortar. THIS is the stuff thats going to eventually drop into your pizzas ! so best to get rid of it NOW.

The BEST joint i have is actually the one that had heaps of excess on the outside, once i ground it back it is a PERFECT joint, solid, smooth and i know it isn't going to drop anything into my pizzas.

So in hidesight maybe making sure the mortar reaches the oven is the best method? what i was trying to do when building the arch was to use as little mortar as possible but now i think that is wrong, in the case that my bricks were not perfectly straight/square so in reality it was silly of me to expect i could get away with "no mortar joints" or little mortar joints.

SOO if you are using non perfect bricks (which i think in reality ever one is ! ) then go with making sure the mortar reaches the inside of the oven, THIS will be further proved in my next post so read on.

Building the arch.... finally

Finally we start the arch bricks, there are 3 bricks deep (this is 2 laid so far) . Our object was to limit the gap in the bricks inside the oven to as little as possible by using as little mortar as possible then filling in the brick gaps from the top, we did the mortar in small batches and spread a good layer ontop of each section, each arch is 10 bricks plus the keystone(brick) in the middle .

this is the last layer, so thats the internal area of the oven, there is a small area of oven still (1/3 brick wide) but that sections roof will be part of the "drop down" area just before the chimney which i will detail in later posts.

back wall and brace

Dodgy photo i know but i wanted to clear out the background so you could really see what i have done here.

at the top is the back wall, i created and cleaned that up first as i know once i get the template in it won't be possible to clean it up, its easy to do as the "fondue" /mortar dries really quickly.

Then i got 4 bars and created a brace around the side walls, the reason is the downward pressure from the weight of the arch bricks may have force the walls to fall over, the bars are simply bolted at each corner and positioned right against the walls. it proved true as i noticed the tension on the bars tighten as i started laying the arch bricks. I plan to concrete the outside over the insulation so that will secure the walls and add strength.

you can see i have the template ready and levelled, i placed newspaper over the top to make it easier to remove the template once the mortar is dried, it will make it easier to clean up the inside as well. No doubt there will need to be some pointing needed to get a good inside finish.

So its all ready to go.

Creating the arch

Now the walls are up its time to layout the dome/arch and check the template fits !!

you can see here i have propped the arch template on bricks, it was slightly to high when we actually went to mortar the arch so i used some different sized bricks to get it level.

oven to small?

Looking at it now it might seem the internal oven space is to small compared to others i have seen but i would say its perfect for what we want to do with it, we don't want to labour for hours setting it up, cleaning it, etc etc.

you should pick the size that will produce the results you want, eg: more size MORE WOOD ! more $$$ each time you want to use it.

this one will do 4 good sized pizzas, roasts, various breads, baguettes , "beer can chicken" etc so its just fine for our family.

Angle bricks for dome

So I have now put in the angle bricks that will help the dome bricks make the arch without to much use of mortar as they are rectangle bricks not shaped bricks.

once this excess was all cleaned up it looked really good, all i do is a scourer and then a sponge, it may look in the image that the back is also angled but it isn't. you can see the ash dump hole infront.

this was just a mock up (no mortar) before i did the angles, just making sure i have the right plan in my head. you can see here left the hole for the ash dump, i have set up the entry width, and i have mapped out the front of the oven to make sure its all going to fit. what you can't see here is the BIG consideration of where the chimney will be, which is almost directly above the ash dump.


Here's my daughter in the oven with some mockup bricks at the front for the drop down bricks which help th esmoke come out of the oven and up the chimney, its called "draw" so google it.

you can get an idea of the internal height by counting the bricks in the background.

this is a good vid for the drop brick "look" http://www.youtube.com/watch?v=revPSeHiJDw&feature=related at 58secs into it, but i can't work out if they have a chimney or the smoke comes out the front???

here you see a good look at my front layout, the dome will be where the angle bricks are, then there will be a front section that has angled bricks to "drop" the smoke, then there is a brick (2 bricks upright) that will be the chimney space. what you can't see in this image is the FRONT FRONT section which will be the arch that SHOULD not get any smoke and not turn black as i am using cream bricks, ALL the smoke should exit before then.

you can see i have plenty of room at the front to achieve this.

the oven door is 34cm wide and 34cms high.

i saw today a statement that the oven door should be 2/3rds of the height of the interior, thus my interior needs to be 51cm ..ish high, i think the sides are that but the top of the dome is @ 70cm+ i think?

Oven Walls done

First thing I did was go through all th ebricks i have and sort them, I sorted them into "dome" bricks, these are the best ones, straight edges - no chips etc. Next is "wall" bricks, once again straight edges but only needed to be on 1 side and i put the chipped corners to the outside. Lastly "whats left" they will be the chimney, back wall bricks etc.
Here I have placed the dome template on th efloor to make sure the bricks get laid at the correct width, you'll notice the white row on the outside, I opted to not cut any of the floor bricks instead i moved the side brick in and added some hebel on the ouside to support the wall. the main reason i did this is it will be easy to replace the oven floor if it gets worn any time in the future as those bricks are not supporting the wall.

I then moved the template up to ensure it was all straight vertically and rendered the outside of the oven to ensure no gaps


I then removed the template and filled the gaps in any bricks on the inside, I had some mortar left over so i added some chicken wire to the sides and back and pushed more mortar into it, once this dries I'll peel the top chicken wire CAREFULLY back and do my next layers (you can see the 2 bricks sitting ontop of the left wall).

This will give me an extra brick height and then the slanted brick to facilitate the angle of the dome, having an angle brick helps reduce the arch angle and the amount of mortar needed to join the bricks.

pizza floor

Finally we laid the pizza oven floor, below are 4 images of the progress. the first


image is the base of sand and on the right is some bricks as guides as to where i'm going to lay the floor and the projected front arches for chimney etc.


I then laid the "fondue" onto the sand, the plan was to place the bricks onto the floor and smack them with a rubber mallet to get them level/even, thus the mortar/fondue would give way to make this happen...WHAT actually happened was the fondur dried really quickly so i had to keep wetting it and it ended up being a real RACE for time. that area you see there is just 65cm sq so it wasn't a large area. if i did it again i would definatel have help and mix less mortar at any 1 time.

As it was i mixed just 30litres (mass), that is 2.5fondue - 1water - 4sand, THUS that was converted to 10litres of fondue - 4litres of water - 16litres of sand.







I put a sliver of mortar between the bricks, i have been told (by an expert) that this helps stop the ash from falling through the gaps and eventually forcing the bricks up thus making you have to re-lay the floor.

We also then "grouted" the bricks to make sure no gaps, it got messy but it was easily washed off with just water.

Final Layout preview

Heres a shot of bricks just placed where i kinda think they will go, its really good to do a dry run like this as i learnt alot just by seeing the gaps in the bricks, the slight missalignments, the odd floor brick thats rocking unlevel, how much side room i have, the actual position of the ash drop, how much room i have at the back and front etc etc.
The BIGGEST thing i learnt here was that the first FIRST thing you should do, as in the very first before you lay the bottom concrete is to choose your pizza oven floor bricks as how they measure up will/SHOULD decide the oven dimensions.

I didn't do this and i'm regretting it as i have had to do a bit of a "fix" to the design to accommodate. I'll need to cut some floor bricks to size, no big hassle but it would of been better if i didn't have to.

I decided to invest in proper base bricks (the white ones) and the proper mortar (fondue), the bricks were $4AUD each and the 20kg bag was $50.

Before you start the dome......

Nows the time to review your plan before you start, look at:
positioning on the slab
internal floor dimensions and the size of floor tiles/bricks you are using.
door positioning
door size in relation to pizza width
baking pan/tray widths to door width
chimmney position
amount of depth at front for resting items from oven
and so much more, visualise the end result, do some brick layouts to help.



You can see here I can tell where the oven is going, the depth, door width, my ash drop and the amount of space at the front of the oven door. Its REALLY good to just do this and look at it. by me doing this I can see I can come forward a bricks width maybe and have a slightly larger/deeper oven. I can utilise the front "drop" to the chimney as this extension.

More on that as I progress.

Hebel Thermo Layer

Once the concrete slab was dry I laid another course of bricks which is the last, this will contain the Hebel layer.
As you can see below I simply cut the hebel to fit with an angle grinder, you could do it with a saw but this was quicker although VERY dusty so wear your mask, glasses, gloves AND ear gear, I would also suggest wearing a hat as my hair was full of dust at the end.

I glued the hebel together for extra strenght, its a special mix for hebel. the hebel is the same hieght as a brick so that left me with a small gap to the top brick because of the brick mortar height, this I filled with a thin layer of sand to make it perfectly level. below you can just see the ash dump hole, it looks small compared to ones I have seen but it wouldn't take much effort to make it bigger in the future as it is positioned at the oven door. At this stage i'm thinking Ash is Ash and small !

Next week we can start the dome.

Top Slab Laid

Before the top slab is laid I have cut a hole through the corragated iron for my ash dump.


I then place a off cut of rain downpipe into the hole so when i pour the concrete the hole remains.

I place the reo and reo-props before laying the concrete.

All done, I let it set for a couple of hours and wiggled the downpipe a few times, Th enext week it was very easy to pull out. Another idea is to line it with plastic wrap, the wrap will be easy to peel off the cement.

top slab gravel

Run with me on this post...

I have poured in a mix of gravel and soil to fill the grooves of the corro to make a flat surface, the reason is I am putting in (cutting out) an "ash drop" so i need to layout the oven bricks to see where to cut through the corro BEFORE laying the concrete, what i will be doing is creating a hole/slot at the oven entry so I need to know now where that entry point will be.


For this I have done a mock layout of bricks and my dome template.

i won't explain these images now as it will be explained once i have done it.

I'll be leaving the gravel there as the concrete will absorb into it anyway thus creating concrete !

top slab support

Now I have put the corrogated iron on top, this was off cuts from a building site thus the angle you see, i just overlapped them and filled the gaps with leftover mortar, i also mortared atround the sides, this way when I pour in the concrete next week it won't seep down any gaps at the edges.

This is solid as a rock, with the L-shape design and the extra reo i put in its not going anywhere !


Here's my daughter standing on top, one of those moments never to be repeated as it will soon be a pizza oven.

10th level

Now that i have done the 9th level and put in the reo i have finished the 10th level which will basically be the surround for the top concrete slab, what i didn't photograph here,sorry, was that i put mortar along the inside bricksso that when i place the corrogated iron down the mortar will fill all the gaps making the back area vermin proof.

the next posts will further explain this.

This level is also the one that i use the lintels on to create the bridge of bricks for the underneath wood storage area and the "ash drop".

I found that the bricks didn't like th elintel, i think becuase IF i was to do another level of bricks it would be all ok BUT as i am using this 1 level of bricks as the "level" to lay the top slab at this stage i can't do the next layer of bricks until the slab is laid.

What i learnt from this is that I started at the back of the structure and ahd it all level but thenonce i got to the lintels it through it all out !!!!, if i was to do it again i would START at the lintel and lay bricks on that and then level the layer from that height.

Preparing for the top concrete slab

So i have now gone up 9 levels of bricks and although i have put in inside supports for the corrigated iron to pour the top concrete slab onto I feel i still need some more support in certain areas.

You can see here all i have done is angle grind some dints in the bricks and run reo rods across it. they are JUST behind the brick where the lintels will go, the cross section of my 2 underneath openings, the big hole at the back and the small gap on the right.

Here is a close up of the groves i created to slot the reo in, i also secured them with a bit of "liquid nails" just so they don't move, the weight once the slab is poured will also secure them.

Oven Door....or NOT?

Well I just realised I must be stupid ! I've come all this way thinking that the only reason i need an oven door is to keep pests out when its not being used. Seriously.... thats what i was told by an oven builder.

His explaination was that you need oxygen for the fire to FIRE thus a door would go out if you suffocated it, sounded logical at the time.

But I never considered a door could be used once you no longer need a flame and the radiant heat from the bricks can cook soo many more things as they slowly cool down.

Theres millions of things you can do after the hot pizza and bread, as the oven cools you can then do roasts, chickens, pies, cakes, glaze a xmas ham and even a low heat Pavlova !!!

SOOO, basically now I'm going to have to redesign the front of my oven because my current design doesn't allow for this to happen as the door was positioned after the vent thus being useless in retaining heat effectively.

What i now need to do is create a "opening tunnel" that allows me to position a door before and after the vent position.

Back to the drawing board ! but better to find this out now the later.

like i said i must be stupid, i've researched sooooo much but missed this.

Level 8

Well up at level 8 now (the distortion is the camera lens !)

Now i have some height i can imagine where the oven openign will be as opposed to my drawings and I have decided to go up another level of bricks.

My design is different to others I have seen, it now willbe 9 levels of bricks then a layer which will hold the top slab of concrete, then another brick level which will have "Hebel" block inside for insulation and then covered with a small amount of sand to make the whole thing level.

getting there !!



You can see in the forground the first layer of bricks for the buffet bar/herb garden and the hole in the middle for water to flow away, i will be lining this with thick plastic inside to stop moisture seeping through the bricks.

YES, i dislike the GREEN poles, working on getting that repainted but haven't decide on a colour.

brick mortar mix

My brick mortar mix AS I am doing it all in a wheel barrow is just:

I use a 10 litre water bucket,

into the barrow i put 3 x buckets of sand (30kg ish)

half a bucket of cement mix (5 kg ish) and a 1/4 of Lime (2.5kg ish)

I mix it all together and then add 5-6 litres of water

REMEBER, you can always add water you can't take it out !!!

What you want is somethign that sticks to your trowl but doesn't slide off your bricks, i mixed a REALLY wet mix once and it just was a wate as sooooo much disappeared into the brick holes, YES you want that but not toooooo much.

Bricklaying, doing corners

Here you see i am now up to layer 6 but i have done the next 3 layer "corners", you can see the "stair case" bricks at the back.

What i have done is spend time on getting the corners level and as you can see i am no longer using the string as the wall space at the back (mentioned earilier) is to tight.

What this allows me to do is spend time getting them all straight and level and then simply fill in the gaps next week.

You can see my design has an L shape hole for wood storage and an "ash drop" this is a good design but creates probs with keeping it all level, its also now very clear my placement of the "odd" bricks and the facade will be those nice whiteish bricks (once cleaned of mortar scraps).

Leveling from as many different angles as possible is always a good thing.

Another angle, teh forground of this shot is the small buffet bar/herb garden at bench height area, as it was rainging i laid the first layer and got it all level and then covered it so rain didn't get into the mortar as it dried.

I've started it now so that as i progress with the oven i can use left over mortar to do some layers in that section, this way i never end up with leftover mortar or half finsihed layers as i go each sunday.

Forget about the dodgy pavers falling over, that will all be fixed up onces the main structures are completed, the reason is THEN I will have solid sides to work against so the pavers don't move in the future

And then there was rain !!

And then the rain came down ! , luckily i have a roof over the project but it was good to see the rain come as I now see that the front of the future oven is not going to be covered by the roof as i have extended forward of the old structure.

The oven doesn't get wet but anyone standing in front of it will be !!

I'll have to ponder the solution but i thought it was worth pointing out this for your consideration in your project.

You can see the back area is a real mess, I think you just have to have a VISION and know it will all be cleaned up asap.

Stringline level

Sorry i have been slack but now i am doing this every sunday time seems to FLY.



Here you see i'm 3 layers up and have got a post on the corner, well all 4 corners but not in this image.

I tied the post with some string (remeber this jobs on the CHEAP) and then that allowed me to run the pink string for the next layer and then move that up the post for each layer, thus get the string level and to the next levels height and its all level.

To be honest this didn't work for me but i DO beleive it is a good system, my prob was at the back I had no room to really maintain the poles and they slipped so i ended up not trusting them.

but i would advise trying this out as it could work for you.

You can also see in this image how I am using the "odd" bricks on the inside where they won't be seen. at th efar back you can see some brown and red bricks, there is the neighbours brick garage wall behind the oven so nobody will ever see the back of the oven.

FREE insulating

Once i have created the dome/tunnel i will need insulation. my research shows that thermal wool insulation VERY expensive.

The other day I found a home water heater on the side of the road and took it home, once i opened it up i found some GREAT foil covered "wool" insulation and large enough to do most of the pizza tunnel

I then stripped it of the foil/wool and it ended up being around 1.8metres high by 1.5 metres wide.