New Build on this side of the Pond

[underpendle]

Cheers Jon

Don't want to regret it later, just ordered enough for 100mm under the hearth. Thanks for the contact. a lot cheaper both product and carriage. if only id known before I got the bricks. Heyho!!!

S

[cobblerdave]

Cheers Dave, Thanks for the feedback.

Would you consider Thermalite/Hebel to be an equivalent of CaSi? Can put a Thermalite layer in for a fraction of the price of CaSi. The bricks as delivered have some damage. Ive contacted the supplier and hope for some recompense. This may be a free delivery? Maybe some money back. Spending a lot of time/money on this and don't want to spoil the job for the sake of a few quid. However it is a consideration.

Yes first oven. Ive bought 76mm so thats what it'll be. Want the ability to bake bread so think this is for the best, Im only building 800mm ID so not big by the standers on here but hope it'll serve all our purposes.

S

G'day
Forno bravo is a us site and the Americans and thermolite is not common. It's cheap and avaliable in Britain and Aust, not as efficient but does the job. I spent my money on ceramic insulation over the dome and covered that with domestic insulation. No pearlite cement in my construction.
Use what's avaliable and affordable I say.
Regards dave

[underpendle]

Been mad busy last couple of weeks so no time to play. Managed to get site a bit tidier so moving forward. If I get finished in time tomorrow I'm hoping to lay hearth out. I plan to lay 12mm tile backer boards on a sand/cement mix with plenty of waterproofer in. then 100mm CaSi also laid on same mix.
76mm fire brick to be laid on a homebrew mix, I'm planning on laying dome directly onto the hearth, Ive given this a lot of thought and think the pro's outweigh any con's.
Just wondering if anyone has any thoughts on this, and am I the only person with a kitchen table looking like this:-)

Cheers S

[JRPizza]

Are you saying you plan on mortaring down your hearth bricks? I don't think that is necessary and is not usually done. I had a wooden center brick holding my IT that I pulled and replaced with a firebrick, so mortaring would not have been an option for me, and although unlikely, I can replace a brick that isn't under my dome if any of them crack or get worn due to abrasion from peels or heavy pots.

[underpendle]

Had thought so yes, Although your points are very valid. Had thought that this would make the bricks easier to level, but you've made me think. I'll give it a go on a dry mix. I guess a fine kiln dried sand would do the trick? Not an option for tomorrow cos I don't have an, but going to be busy till late afternoon anyway so prob run out of time before I get that far.

[JRPizza]

I guess I got lucky - my board sat very flat and I selected my bricks such that I just laid them without any dry mix etc. I "might" have been able to get them flatter, but I also might have spent way too much time for what I felt were diminishing returns on my time.

[underpendle]

Did you bed the CaSi Board?

[JRPizza]

No, didn't need to. We got the hearth pretty flat and level.

[david s]

" I'm planning on laying dome directly onto the hearth, Ive given this a lot of thought and think the pro's outweigh any con's."

if if you are insulating the floor with 100 mm of cal sil, it doesn't make much sense to sit the dome directly on the supporting slab. You will lose heat from the dome conducting straight into the supporting slab. The whole oven including the dome should be encapsulated in insulation.

or do you mean that the dome will be sitting on top of the firebricks?

[underpendle]

Thanks David. Yes will be building directly onto the firebrick

[underpendle]

Hi All.
Been spending a little time getting my site ready, therefore little progress for a couple of weeks but moving on. Tonight I started cutting the bricks for my hearth (before wearing out an old diamond disk stopped play). I intend to cut the hearth to fit within the dome with a small expansion gap between the bricks and the hearth. I have read on other threads that the norm is to fill this with cardboard during construction, which will subsequently burn off. My concern is that the gap then fills with ash etc which will in time become uncompressable. Does this matter or will the particles tend to move? in which case why not fill with sand in the first place? Has anyone tried placing a fibre rope in this gap, say 10mm to prevent this?

Hope to have the roof on in the not to distant future and then work can hopefully progress apace. Ive told the wife that we are cooking the beef in here at Xmas!!! I have however not given a guarantee as to which one.

S

[underpendle]

Had an hour free this aft so managed a start!! Ive cut insulation and hearth bricks. Gone with 100mm CaSi and am cutting the hearth to fit within the dome, got a bit concerned about expansion if dome built on top of the hearth?
I will leave an expansion gap round the edge using cardboard for now as mentioned elsewhere. does anyone have any views on using a fibre rope in this gap? or just leave to fill with ash. Alternatively could remove card after first course and fill with sand? Plan on bedding the hearth on loose on sand to get a better level before I start building proper. Going to end up working most of the wkend so can't see me getting much done but might get first course cut and ready to roll with a bit of luck.

S

[underpendle]

Spent an hour messing this eve and struggled a bit getting the hearth levelled up with dry sand. Hope to have another go tomorrow with a wet 50/50 sand clay mix. Read somewhere that smearing the CaSi with fat prior to trying this is advantageous to prevent CaSi sucking the mix try. This seems to make sense.

I'm getting tempted to go back to plan A and placing the dome on the hearth and bedding the hearth on home-brew.
Does anyone have any views on this?

[SableSprings]

Take a notch trowel (pic below) to make the pattern in your damp sand/clay mix. The grooves/spaces allow you to tap the hearth bricks level as you set the floor. Gives the base mix a place to go as you tap/press down. Laying the sand/clay mix down (1/2" or 10 to 15 mm - thick is plenty in most cases) and making it level first, will make things will go easier. Use a board or construction (long) level and simply pull across the sand/clay (like leveling a cup of flour). Then take the notch trowel and pull it lightly at about a 45 degree angle across the whole area. You want to create those grooves all over your level surface, letting the excess sand/clay go off the sides. Now as you start to lay down your bricks, you should be able to set them on the grooved surface and lightly tap them down with a rubber mallet to level. Basically, this is the same technique used to set tile on thinset mortar. ...and as you've found out, dry sand doesn't work very well for leveling a WFO cooking floor.

Yes, smearing the CaSi with fat (or butter) is an option but you can also simply use a can of spray oil (we have several products in the US to keep food from sticking in a pan during a bake). I think you could even just lay down a layer of parchment or wax paper to keep the moisture in the sand/clay mix long enough to allow you to set the cooking floor. Remember you don't need this mix to be wet...just damp enough to hold a shape.

As to placing the dome on the hearth or just outside the perimeter...lots of successful and happy builders here with either method. Both have pros and cons...my impression is that being able to replace a broken/cracked floor brick with the perimeter set is what most people comment on. However, I really haven't noted that many folks on this forum that have posted on having to replace any of their cooking floor bricks. I've had my oven in place for over seven years and have baked a total of almost 3,500 loaves of bread and a "dough on the floor total" (biscotti, rolls, pizza, bread, etc.) of almost 4,600 pounds (just under 2,100 KG). My dome is just set (not solidly mortared) on the cooking floor and I'm not concerned about having to replace any bricks yet .

What have noticed is that on pre-cast domes, if you level the hearth and then set the dome in place around the hearth (leveled cooking floor) and on the pieced insulation base board, the weight on the perimeter of the board can cause the floor to tip up in spots (losing your nice level cooking floor ). When we build, this doesn't seem to come up (no pun intended).

Hope this helps a bit.

[underpendle]

Cheers Mike. Yes it does, I had been using a notched trowel but as you say dry sand doesn't lend it's self to this. A question if I may, when you say your dome i set on the floor, I assume you mean laid on a similar sand/clay mix?. I had considered this but was erring toward laying on home-brew?

Thanks

S