42" Pompeii Oven in Jamaica

[wthwaites]

Wet insulation is one of the main issues with poor oven performance, it causes the insulation to become a heat sink. If I remember right you have IFBs then some type of CaSi of unknown specs on top. It would of been a lot easier to have installed weep holes in the concrete hearth before the oven started, I would try using the oven several times and see what the performance is. If you feel substantial heat transmitting down to the concrete slap you have wet IFBs and or CaSi then you many have to rethink the weep holes in the slab.

Thanks a lot for this advice. I already know that the board and IFBs are soaking wet from our rainy season. I just assumed that the cure fires would slowly dry them out. If that's not the case, then I guess its back to the drawing board...

Don't forget to install a vent in the apex of the dome in the stucco to steam and egress out.

I don't understand what you mean. I'm doing a squirrel tail chimney so the flue will be sitting on top of the dome. You're referring to a separate vent? How would I do this?

[UtahBeehiver]

Wet insulation is one of the main issues with poor oven performance, it causes the insulation to become a heat sink. If I remember right you have IFBs then some type of CaSi of unknown specs on top. It would of been a lot easier to have installed weep holes in the concrete hearth before the oven started, I would try using the oven several times and see what the performance is. If you feel substantial heat transmitting down to the concrete slap you have wet IFBs and or CaSi then you many have to rethink the weep holes in the slab. Don't forget to install a vent in the apex of the dome in the stucco to steam and egress out.

[wthwaites]

Currently adding 1.25" of additional thermal mass to bring to a total of 5" including the firebricks.

I'm now thinking about how the final layer of my dome should be done after laying my 4" of insulation FB. Is stucco the best option? What is the best recipe mix for this?
Also, I read that drilling holes into the slab where my FB will be should help in the future cure fires with moisture loss and prevent cracking. Is this true and needs to be done or is it unnecessary?

[MarkJerling]

**Update**
Finally got to closing up the dome! I put the final keystone piece in today!
The last few courses aren't the prettiest, but its functional and I'm happy with it.
The bricks I've been using are 3.75" deep, so I'm thinking that the next step will be to do either an additional 0.75" - 1.25" mortar render for additional thermal mass. After that I'll install the chimney on top of the dome; I've decided to try the Squirrel tail design...

That looks good! I look forward to seeing your squirrel tail.

[wthwaites]

**Update**
Finally got to closing up the dome! I put the final keystone piece in today!
The last few courses aren't the prettiest, but its functional and I'm happy with it.
The bricks I've been using are 3.75" deep, so I'm thinking that the next step will be to do either an additional 0.75" - 1.25" mortar render for additional thermal mass. After that I'll install the chimney on top of the dome; I've decided to try the Squirrel tail design...

[wthwaites]

Thanks Petter !

[Petter]

Looks good!

[wthwaites]

Finally, some good weather this week - SUN!
My first attempt at laying the entry arch was a fail - I tried to remove the door template and the arch broke and fell over
However, I tried again, and managed to lay both the vent and entry arches without issue. and went up a few courses (starting course 7 above the entry arch). Building onto the entry arch provides additional strength so I don't think there will be any issues going forward...let hope so!

[MarkJerling]

That's looking very tidy!

[wthwaites]

Tropical Storms are still holding up progress!

However, got the 3rd course and entry arch in. I should be able to get the vent arch up when the weather allows this week, and hopefully the 4th course for the dome too...
I seem to be running low on the bricks i have been using for the dome, and may have to switch to a different "heavier duty" type that i had sourced here on upward. (More details in post #2 for those interested.)

[MarkJerling]

I think that looks good. Onward and upward!

[wthwaites]

**Update**
Onward with the build!
We have been having heavy storms where I am, so I haven't made as much progress as I hoped. However, between the rains, I have been cutting bricks to size and managed to lay the first and second courses.

The IT tool is definitely a life saver; you all weren't exaggerating when saying it is the most important tool to have for this build. I have also been using the dome calculator found in the "Tools, Tips and techniques" thread; it has been very helpful. With the Miter Saw for my cuts, I have been doing the side tilt and side angles based on the calculations from the spreadsheet and it seems to be going well - Not 100% accurate but close enough for my mortar joints to be pretty small. What do you think from my pics??

Yes, I know that I haven't really started the entry door, but will be doing that before I go any higher. That will most likely be my next update.

[wthwaites]

wthwaites - wow - great progress!
I don't think you will have a problem with the slight reveal from your rowlocks.
The important thing here will be designing a true and strong IT to ensure your build going up maintains its shape, course by course.
You can decide whether to make it adjustable (as many builders here do - and for good reason) or fixed (I did - seemed to be ok).

This tool will determine your angles per course and all your cuts - as such, the 1.5" you see now will just be part of your build going up (the first few courses are a gentle slope in anyway.

Great stuff mate!
Keep it going!
Barry

Thanks Barry!

I made my IT tool adjustable, but haven't changed anything since I set it. You're right - the first few courses so far have been very slight and gentle in terms of slope. So far so good...

[Baza]

wthwaites - wow - great progress!
I don't think you will have a problem with the slight reveal from your rowlocks.
The important thing here will be designing a true and strong IT to ensure your build going up maintains its shape, course by course.
You can decide whether to make it adjustable (as many builders here do - and for good reason) or fixed (I did - seemed to be ok).

This tool will determine your angles per course and all your cuts - as such, the 1.5" you see now will just be part of your build going up (the first few courses are a gentle slope in anyway.

Great stuff mate!
Keep it going!
Barry

[mongota]

First course looks fine as is. Time to go higher!