MakaDemian 37" Brick Oven Build with round base in BS. AS.

[MakaDemian]

Ok, i will try to do it short coz I'm in a bit of a hurry here, so i hope you could help me out to decide and choose the correct materials for this. I'm gonna be honest here and i have to admit that I'm a little overwhelmed and confused with all the materials and combinations available, so that's why im trying to do it fast and without pain.
The oven dome is gonna be 37" (94cm) with all refractory materials and i have a total of 55.2" (140cm) base made of red clay bricks.

The thickness of the slab is gonna be 4" with a mix of double 10mm (3/8") and 6mm (2/8") rebar.

In the next post i will tell you about what I'm thinking about floor and dome insulation.

[MakaDemian]

This is my floor build idea, i will upload a pic for the dome insulation later.

[Giovanni Rossi]

For your question marks...

I don't see a layer of small tiles in your drawing. This is important!

Take a look at page 2 of my build for info on weep holes and tiles. Note: post #22 has 3 photos that are not previewed.

And see one of Joe Watson's builds for more info and some nice photos: Simmental Farm 36" Pompeii and 48" Rumford Style Fireplace

The tile/weep hole scheme is simply for allowing any moisture that finds its way into the oven a pathway for escape.

The only reason you need the garden cloth / landscape fabric is because you decided to use a perlite/cement insulating layer. The cloth supports the mix while it hardens so it doesn't sag into the spaces between the tiles and block the path for the moisture finding its way to the weep holes. If you use sheets of mosaic tiles that are mounted on a web backing, just place the sheets upside down and the web will serve the same purpose as long as you don't force the mix into the gaps with too much pressure. Also, don't put a tile directly over any of the weep holes.

I'll let the more experienced builders weigh in. But, I don't think you need the added expense of using refractory mortar in your perlite insulation mix. A Portland cement based mix should work fine.

[MakaDemian]

Thanks Giovanni,

1) About mosaic tiles sheets i already made a comment in other thread saying that i prefer not to use them, its too weird for me the tiles are glued with a cardboard, sorry. Its gonna be a circular base i dont see cutting out the tles to fit perfectly the circunsference. And to be honest the only person i saw using upside down tiles (https://www.youtube.com/watch?v=wk6TxMP30nM) he didnt even could cut to shape. I 've seen a lot of slab/vermcrete/perlcrete constructions without any of these (i mean upside down mosaic tiles and weep holes), so do I have to assume that all these people has or had moisture/water retention problems on the slab?

On the other hand, Sable Springs says: " Also want to stress the recommended layers: hearth (concrete supporting slab) with 4-5 weep holes, porcelain/glass (mosaic tile square sheets) laid backing side up, garden cloth (if not using tile squares), perl/vermicrete, thin layer of sand/clay for leveling cooking floor bricks, and finally your cooking floor & dome."
I think he says or tiles or garden cloth but not both. that's why i was asking about garden cloth coz i thought it was a more reliable option for me.

I'm really confused with all this mosaic tile square sheets recomendations, coz it's the first time i heard this recomendation after seen hundreads of builded ovens, i cant even see them used in most of Forno bravo ovens.

So what would be another option to avoid moisture without using mosaic tiles ?

Can you give more info about garden cloth specs ?

[MakaDemian]

2) I dont want to loose one of my main doubts in this thread that is the floor idea that im planning to do, which i dont have an answer yet.
Basically i wanna know if resting and glueing the refractory bricks directly into the mortar thin layer that is over the perlcrete is enough for insulating the dome on the floor. I was thnking installing the ceramic fiber board only inside the dome as part of the dome floor and not under the bricks. And as you can see im not planning putting the bricks dome over the refractoty tiles coz they are gonna be loose, to be available to change them in a future without any issue.
What about dry sand/clay between CFB and refractory tiles ? Do i have to mortar the CFB to prevent sand/clay seepage through the slits of the CFB. Could i use a ceramic fiber paper (1260C°/ 3mm) between CFB and sand/clay to prevent leaks through CFB joints ?

[SableSprings]

Giovanni covered your tile/garden cloth question very well. He is also correct that you don't want to use refractory mortar in your perlite insulation layer (and the top cap is not necessary). If you were planning on using refractory mortar you'd find it would set way to fast to create an even layer of 5:1 and end up being a costly waste of time & money. Simply use 1 part (by voume) Portland cement (not pre-mix) to your perlite. A mix of 50/50 perlite/vermiculite with a handful of clay mixes even better for the 5 parts portion. No need for the top cap on this layer, make it level as you can. After a week or two that layer should be well set and dry enough to lay the ceramic board down and use a thin layer of sand & clay simply to make sure all your cooking floor bricks create a level surface ( brick thicknesses can/will often vary ).

Your perlcrete under layer will still contain a lot of water even after a couple of weeks air drying...leave it uncovered as long as you can. Good planning and having your work reviewed here to get your best results. Looking forward to you build progress. By the way, your stand is going to be a lot of work using red bricks. Any reason you aren't going to use concrete blocks? You can always put on a stone or brick facade later...

[MakaDemian]

Giovanni covered your tile/garden cloth question very well. He is also correct that you don't want to use refractory mortar in your perlite insulation layer (and the top cap is not necessary). If you were planning on using refractory mortar you'd find it would set way to fast to create an even layer of 5:1 and end up being a costly waste of time & money. Simply use 1 part (by voume) Portland cement (not pre-mix) to your perlite. A mix of 50/50 perlite/vermiculite with a handful of clay mixes even better for the 5 parts portion. No need for the top cap on this layer, make it level as you can. After a week or two that layer should be well set and dry enough to lay the ceramic board down and use a thin layer of sand & clay simply to make sure all your cooking floor bricks create a level surface ( brick thicknesses can/will often vary ).

Your perlcrete under layer will still contain a lot of water even after a couple of weeks air drying...leave it uncovered as long as you can. Good planning and having your work reviewed here to get your best results. Looking forward to you build progress. By the way, your stand is going to be a lot of work using red bricks. Any reason you aren't going to use concrete blocks? You can always put on a stone or brick facade later...

So to be sure garden cloth only on top of the ceramic tiles if not it has no functionality ? What happens if i dont use ceramic tiles is the end of the world or there is another solution for moisture ?
The 1/2" cap of refractory mortar (or maybe refractory concrete) is just to level the floor, i have seen this in lot of oven constructions. Of course i wouldnt level until passing two weeks the perlcrete is dry.

[SableSprings]

Sorry Makademian, we were both writing at the same time. Yes, resting the dome bricks on the perlcrete will provide adequate insulation and you do not want to glue/mortar the cooking floor bricks down. They will expand & contract during oven cycles enough to break/warp any kind of bond you attempt. Misting the sand/clay mix & using a notched trowel as a bed for the cooking floor is all you need. We haven't had any reports of this layer escaping down through the cracks. Your boards are in place and held there by the time you're laying on that mix. It fills any gaps you've got and can't go anywhere.

As to the ceramic tiles above the weep holes, we've been recommending & using this upgrade concept for several years now...it's cheap to do and very effective. It's your build but we'd all like you to avoid future problems...

P.S. I didn't look back at your initial post & picture of the completed red brick support base...so obviously my question about not using blocks was irrelevant. Do you have any wood storage plans?...appears using the space below the oven will be a bit tight to access.

[Giovanni Rossi]

Not sure why you have an aversion to the mosaic tiles. This is a relatively new addition on this Forum which is why you will not see it on older build threads.

This is the advantage of working with sites such as this where there is a collective of minds that try new techniques and products and share that knowledge. I searched the net for wood-fired oven knowledge on and off for about a year before I realized most of what I needed was on this Forum. And, being able to bounce ideas and ask questions was invaluable as I worked through my build.

I always caution new builders to take the time to do the research and not rush the build. These ovens can be expensive to finish in both materials and time. It would be a shame to have a finished product that doesn't meet your expectations. There are certainly many ways to construct the various parts. Many times it comes down to how you want to use the oven, how much money you can spend and what skills you possess. However, there are critical aspects of each build where you'll want to heed the advice of the members who've been through it. There are guys helping others on the Forum who do this for a living. There are others who have built multiple ovens and if If you take the time to read their posts, you will realize that they have updated their subsequent builds with info from this Forum.

One last comment on tiles and water infiltration. Obviously if your oven and stand will be undercover and out of the elements, your risk of water infiltration is less.

[david s]

Here's a drawing that may help explain about the function of the tiles under the insulating board.
The tiles lift the board up so they won't have wet feet. Apart from the water resistant calcium silicate board and Foamglas, all other insulators will act like a spongeand can suck up a lot of water. Secondly it is the spaces between the tiles which act as drain channels that allow moisture to find its way south to the weep holes. The only purpose of the weed mat, (or turning the tiles upside down, using the net the tiles are glued onto to stop the vermicrete falling through), is if you were casting vermicrete over the tiles, because the channels would get blocked up. You don't need it if using a solid board. Also in that case the tiles can be spaced much further apart, making it easier not to cover the weep holes with a tile.

Regarding dome over the floor tiles vs dome beside the floor tiles, as you've pointed out, replacement of a floor tile under the dome would be nigh on impossible if the dome is on top of it. This is actually not a concern because if any floor tile requires replacing it will always be those in the centre. The downside is that cutting the perimeter of the floor tiles requires precise cuts which takes way longer and probably results in more wastage. they can be cut quickly and roughly if the dome sits on the top because their edges will be covered with insulation.

The dry sand/clay mix, allows movement ather than setting like mortar and only serves as a leveller because the thickness of the floor tiles usually varies a little (up to about 1 mm). The tiles should be laid loose to allow for the fairly high temperature difference and therefore difference in thermal expansion for individual tiles.

You will find it hard to apply the outer layers because of the corner and poorer access to the sides and back, as well as an annoying little triangle behind the oven in the corner that is very difficult to find a use for, but I really like the look of your build so far.

[MakaDemian]

Yes, resting the dome bricks on the perlcrete will provide adequate insulation and you do not want to glue/mortar the cooking floor bricks down. They will expand & contract during oven cycles enough to break/warp any kind of bond you attempt. Misting the sand/clay mix & using a notched trowel as a bed for the cooking floor is all you need. We haven't had any reports of this layer escaping down through the cracks. Your boards are in place and held there by the time you're laying on that mix. It fills any gaps you've got and can't go anywhere.

Yeah, if you say so I'm gonna leave the tiles loose over the sand/clay and the bricks dome will be beside the floor tiles and not over them
.

As to the ceramic tiles above the weep holes, we've been recommending & using this upgrade concept for several years now...it's cheap to do and very effective. It's your build but we'd all like you to avoid future problems...

Ok, you are all people insisting too much with this that you are starting to convince me but the problem is that i dont have the spec sheets of the ceramic tiles that i need, You know I leave 8700 miles away from USA and the material that is common for you to get its not for me. I can get some cheap small tiles that i dont know if they are the right ones, thats why i need the specs (density, psi, material at the back of them, thickness etc) I think we call them in spanish "Venecitas" but im not sure if is the same material..

Is this the right ones ?



OR THIS ONE?

P.S. I didn't look back at your initial post & picture of the completed red brick support base...so obviously my question about not using blocks was irrelevant. Do you have any wood storage plans?...appears using the space below the oven will be a bit tight to access.

The wall of red bricks are 23cm thick so the slab will be supported on the largest face of the brick and i put a double 3/8" mesh rebar and 2/8" mesh rebar too.
The slab will be at least 4" (10cm ) maybe 4.33" (11cm)

the space height below the slab is 23.6" (60cm) im gonna use it for woodshed but stored with bags, I will not put loose wood there..I'm gonna install a steel door too down there to keep closed that area.

[MakaDemian]

Not sure why you have an aversion to the mosaic tiles. This is a relatively new addition on this Forum which is why you will not see it on older build threads.

I dont know the material and i dont know if the same material i can get in my country is the right one, What are the pro test that you all people made over density psi, thickness on them?. How do i know that the ceramic tiles im gonna use are gonna support all the damn weight on it ? Is there any risk that the tiles break coz of the overall weight?
What are the specs of the tiles that i need to buy? coz i can get diffeent kind of tiles, i mean material , thickness, density, etc, etc, etc. Take in mind that the materials that are common for you in your country are not the same for me.

This is the advantage of working with sites such as this where there is a collective of minds that try new techniques and products and share that knowledge. I searched the net for wood-fired oven knowledge on and off for about a year before I realized most of what I needed was on this Forum. And, being able to bounce ideas and ask questions was invaluable as I worked through my build.

I dont have a doubt about that, in fact that's why i'm here.

I always caution new builders to take the time to do the research and not rush the build. These ovens can be expensive to finish in both materials and time. It would be a shame to have a finished product that doesn't meet your expectations. There are certainly many ways to construct the various parts. Many times it comes down to how you want to use the oven, how much money you can spend and what skills you possess. However, there are critical aspects of each build where you'll want to heed the advice of the members who've been through it. There are guys helping others on the Forum who do this for a living. There are others who have built multiple ovens and if If you take the time to read their posts, you will realize that they have updated their subsequent builds with info from this Forum.

Ok i understand that, but can you understand me ? I mean i have seen a lot of oven construction out in the open, never seen that idea, yeah i know its something "new" but doesnt mean its not still weird.
Did you know that if the issue here is moisture/water that flows between slab and perlcrete there are other materials you can use to raise the floor and drain water? I've talked with two arquitects and told me that once the perlcrete is completly dry it doesnt absorb water coz it mixed with cement... i dont know.

One last comment on tiles and water infiltration. Obviously if your oven and stand will be undercover and out of the elements, your risk of water infiltration is less.

Yeah, i was planning to cover all the oven and base with some heavy duty cover sheet, maybe double cover too.

[MakaDemian]

Other issue here is the weep holes, once the slab is dry how do i know where to drill all the way down without drilling the rebars ?

[MakaDemian]

I was talking with one of the technicians of this product: It's called PerliTemp and it comes in boards same as calsil or CFB.
They compare it with Calsil and has a lot of advantages against it. Mainly in matter of water absortion is way better. The main problem is that you need at least 4" thickness for 500ª C heat and the density is only 220kg/m3 aprox.
There are not blankets, only boards.

I couldnt get the english version sorry:
SPECS: http://www.perfiltra.com/files/files...esentacion.pdf
PerliTemp VS CALSIL: http://www.perfiltra.com/files/files..._de_calcio.pdf

It says: " Perlitemp®, with the addition of high resistance fibers, considerably improved its physical properties being located at values of 95psi – 110psi, narrowing the difference with Calcium Silicate."
"
"Perlitemp® has a typical value of 96psi, greater than 60psi according to ASTM C-165,Calcium Silicate has no value relative greater resistance to compression."


THERMAL PERFORMANCE vs CALSIL

[Giovanni Rossi]

I'm not sure what more we can say. Providing a path for moisture expulsion is a reasonable addition; but your oven will function without it. Again, the importance depends on the environment in which your oven will reside.

If you take the time to research the Forum you will find builders who live in tropical locations and have offered their take on moisture infiltration.

If you take the time to research the Forum you will find many examples of the type of ceramic tile being used. Properly fired tiles should easily support the distributed weight of the oven. If David S is still following this thread maybe he can offer better direction and put your mind at ease.

If you take the time to research the Forum you will find a lot of information about moisture penetrating pericrete.

If you take the time to research the Forum you will find examples of techniques to build weep holes into your plan before you pour the concrete slab. Or, you could just measure and record some locations in your rebar grid so you know where to drill.

I'm going to move to the sidelines and enjoy following your build. Buena suerte con tu trabajo!