Curing, Cracks & Other Kentucky Conundrums

[Ken524]

Re: Curing, Cracks & Other Kentucky Conundrums

Today I discovered, without a doubt, what is causing my headaches.

The good news is that my (lack of) masonry skills are not at fault.

The bad news...
It's the Kaowool insulation board that the oven is sitting on that is causing the problems. When this stuff gets wet, it turns to mush. The left, front edges of the board are wet due to condensation, leaking rain water, and leftover moisture from laying bricks.

So guess what's happening? The left arch support is slowly sinking into the board. That's what caused the initial arch crack. Today I noticed that my landing floor bricks were buckling a bit (they are mortared together and to the support). That's what tipped me off that the Kaowool was the issue.

I attached a picture of the support on the Kaowool, with a piece of fresh, dry Kaowool next to it. You can see the difference in height. Ouch. The issue may not be as bad as I first thought because I suspect the whole oven has settled a bit into the board.

After I got over my panic attack and temper tantrum, I decided that the best course of action right now is to simply start firing the hell out of the oven to drive the moisture out of the board. When dry, the Kaowool board is very rigid. So, once the moisture is out, there shouldn't be any further settling or damage. At that point I'll go back and repair whatever damage there is.

JAMES: Can you guys put a notation in the Pompeii plans recommending future builders to NOT use Kaowool Insulation Board under their ovens? This stuff is inappropriate for use under an oven. I would hate for someone else to go through this.

[asudavew]

Re: Curing, Cracks & Other Kentucky Conundrums

Wow!

I would of never expected that.
At least you figured out the problem, and hopefully the solution.

I think my problem was even lower. I think my slab actually settled causing my crack. It seems it actually runs from the back, over the top(but much smaller) and around to my arch... the same spot my brick fell out.

I hope it is done, and I hope yours is done!

Fire that puppy and get it water proofed.

[Ken524]

Re: Curing, Cracks & Other Kentucky Conundrums

Fire that puppy and get it water proofed.

AMEN!! That's the plan.

[asudavew]

Re: Curing, Cracks & Other Kentucky Conundrums

AMEN!! That's the plan.

Don't forget to cook along the way Ken!

If you have one of those handy kitchen bread makers, they work great for making dough!

[dmun]

Re: Curing, Cracks & Other Kentucky Conundrums

It's the Kaowool insulation board that the oven is sitting on that is causing the problems. When this stuff gets wet, it turns to mush. The left, front edges of the board are wet due to condensation, leaking rain water, and leftover moisture from laying bricks.

I'm surprised. I would have thought it was a similar product to the H-W insblock19 that I used, and that was pretty much under impromptu covering and a leaky temporary roof for an entire winter, spring, and summer. It got wet numerous times, and it looked pretty much the same when I entombed it in insulating concrete as it did the day I lay it down. (In wet concrete)

[Acoma]

Re: Curing, Cracks & Other Kentucky Conundrums

I used Insblock 19 too. It seemed durable to water and wet mortar. I guess the Kaowool is not of equal properties. Sorry Ken.

[Ken524]

Re: Curing, Cracks & Other Kentucky Conundrums

Just keep your collective fingers crossed in hopes I can get this stuff dried out before further damage.

[Acoma]

Re: Curing, Cracks & Other Kentucky Conundrums

Ken, if you still have lots of moisture, go for it, doing strong fires and maybe go on high with an electric heater from below. I had my electric heater on full time underneath the hearth and the Insblock felt warm..The hearth even cured better too. Attach from both sides.

[jwnorris]

Re: Curing, Cracks & Other Kentucky Conundrums

<snip>
It's the Kaowool insulation board that the oven is sitting on that is causing the problems. When this stuff gets wet, it turns to mush. The left, front edges of the board are wet due to condensation, leaking rain water, and leftover moisture from laying bricks.
<snip>
JAMES: Can you guys put a notation in the Pompeii plans recommending future builders to NOT use Kaowool Insulation Board under their ovens? This stuff is inappropriate for use under an oven. I would hate for someone else to go through this.

I built a modular FB Casa110 and used SuperIsol under the floor. In hindsight this thread is interesting, and we can all learn from it.

While I did not have the same issues with residual moisture from bricks and mortar, when I set the floor I did attempt to mortar the sections to the board.

The SuperIsol wicks so much moisture from the mortar that it was impossible to set in this manner. We tried to saturate the board and were unsuccessful in preventing the wicking of moisture.

However, the board stayed rigid the whole time. Obviously, heat is not the only issue when insulating the floor.

J W

[RCLake]

Re: Curing, Cracks &amp; Other Kentucky Conundrums

Ken, Sorry for your floor problems, if I remember correctly that insulation board was expensive. I've order my insulation board so this won't help me but I would like the insight from our experts on using cellular concrete - this is what they are using for structures on some houses now. I don't know enough to say it would stand the weight or provide the correct insulation property. One salesman for the boards said it was very similiar to this.

This may be a hairbrain idea, but it is something that may be readily available and less expensive.
Aerated Concrete, Lightweight Concrete, Cellular Concrete and Foamed Concrete

[dmun]

Re: Curing, Cracks &amp; Other Kentucky Conundrums

I love it, AAC legos



We've talked before about AAC, but I don't think anyone has built an oven of the stuff yet, at least that that they've told us about

[Ken524]

Re: Curing, Cracks &amp; Other Kentucky Conundrums

if I remember correctly that insulation board was expensive.

Yep. One of life's cruel little ironies . Both the dealer and the engineer I spoke with at ThermalCeramics agreed the Kaowool would be good for the job. I forgot to ask about it's compression properties when wet. Oops!

[Acoma]

Re: Curing, Cracks &amp; Other Kentucky Conundrums

You forgot?! Why not the idiot engineer! That is his job, pry questions to confirm the product fits the need. You need to explain to them that their lackk of knowledge in confirming the uses to what they sell is costing you the stability to what you spent hours and hours building. One thing I learned while in the technology industry was that our engineers pried every door open to be sure all was fitting (needs and solutions).. I apply that to my every day life and notice how so many sales people and technical people just ASSUME the buyer knows. If that was the case, why do they have a job?

[Ken524]

Re: Curing, Cracks &amp; Other Kentucky Conundrums

Robert,

I'm not angry at the ThermalCeramics folks. They described the performance of their product based on the specs I gave them. They can't read minds. Stuff Happens, life goes on. I'm not really here to vent (I do that with my wife ); just to warn others getting ready to build to stay away from Kaowool Board (Kaowool blankets work great!).

The oven seems to be stabilizing as I fire it. Even when wet, there is only so far the board can be compressed. I suspect the worst has passed. I got the dome white again this morning before heading to work. It's really cool to see how the dome goes white faster with every burn.

A couple more hot fires and I think I will be ready to continue with insulation and enclosure.

[Frances]

Re: Curing, Cracks &amp; Other Kentucky Conundrums

We've talked before about AAC, but I don't think anyone has built an oven of the stuff yet, at least that that they've told us about

I thought Carl was using a similar product under his oven.
http://www.fornobravo.com/forum/f6/t...tion-2527.html And it says in this thread how AAC becomes brittle with the heat/cool cycles.