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  #41  
Old 02-09-2011, 12:33 AM
Peasant
 
Join Date: Oct 2010
Location: ca
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Default Re: Wrong dimensions - Help!!

Hey lwood and all-
I really appreciate the input.
Ok, here's the thing. We have been good honorable citizens with someone who for 10 years has delivered pretty consistently. By good citizens, I mean we felt comfortable dribbling the money out all through the job until it went on just too long. So we've paid out a lot for what is now sitting there. If a fix *can* be done, and he won't or can't accomplish it, we'll have someone else do it.

*But* - starting over? Budget got spent already for the project. So let's keep at the creative grindstone here. We've already sent the mason a letter establishing our boundaries and next steps (including spending it elsewhere if he doesn't fix it, all the way to functional, according to our direction). So we are free to try with or without his help at this point. Only because there's a good history will we let him try it- but from here out it is completely on our terms.

So:
Order of fixes:
--Step one, drill hole and experiment. if drilling a hole at 63% height fixes it, great.
--Step two, plug it up and put a ceramic kiln shelf about 8 inches down from dome peak, so the 15 inch high door goes 63%. Remember, door is 15 high, but flue is 18 high, an is located inside the door, not outside it. So smoke draws up at 18 even if the door is closed. But we can block that flue completely simply by taking off the vent cap above and turning it flat side down on the pipe. So do we need to match the 18 inch high flue down to 15 inches door height?? If so, perhaps just an inserted metal ring the diameter of the flue can be inserted into it, and jut down to the top of door level, or a piece of metal can be made to make a fake "sill" containing flue opening up the pipe. Then experiment.

Last step, if the floor is still not heating and holding temp - would by deduction have to be it's insulation saturation.

So- Wet insulation is insulation cold and drawing heat. But would some thin sheet metal on the existing floor, covered with a new layer of brick, substitute in dry heat mass to fix this, or would all that heat just conduct right down through it, through the metal and original floor? Waste of work and material?

If it would not fix the floor, could we chisel up the existing floor (within the internal diameter of the dome), then dig out the vermiculite below it, and put something down there below the vermiculite to keep it from sitting directly on the slab? Or-use some other kind of material to insulate that is not so it is not water attracting like vermiculite is?? Anyone know why we've seen guys on utube breaking up glass into the under-floors of their hornos in Mexico when they build them? (Man if that works, I now recall we have a 30 gallon can full of broken glass that got forgotten behind the barn when we moved our recycling storage. Is it possible that there is another material than vermiculite that might work in a wet environment? As it is, the way this slab was built, there were two inches of reinforced concrete put down onto ground level *before* the vermiculite was put on top, so the vermiculite now sits two inches *above* the ground level that is wet. That slab was poured into a wood mold, and then the vermiculite went on top of that in the mold. Although vermiculite can absorb water, is it possible that it, once dry, won't pull up that much moisture ( I mean really water) vertically like a sponge or siphone from the flat top of a 2 inch raised slab of cement on which it sits?

If that is possible, then of course the dome walls are still sitting on the original vermiculite, if it is down to ground level on cement. But heat is higher on walls, and reflects downward from a (functional) ceiling, and we don't cook right against the walls. So do we need to care about what's going on beneath the rim of the dome base, really?

On a parallel thought, I teach wilderness skills and so of course have a couple of primitive shelters on our land here. One of them is my private meditation hut and consulting place for students. I built it kind of hybrid: since it's location is toward the bottom slope of our acre the ground can be quite wet and muddy in winter. So I went modern hybrid a little. Instead of willow saplings, I used large redwood branches from our giant trees nearby as uprights for the dome (to take many more years to rot). I raised a rim of cement up about 10 inches above ground level around the diameter of the floor and upright branches to shed outside water from the roof in the rain, outward. Then onto what would now have been the dirt floor (with the rim, now appearing to be a "sunken" floor - water saturated - I put
a few inches of nice pea gravel to raise the floor above the surrounding ground level where the water travels. Through wet winters, I have a nice dry floor. I'm sure plenty is wet below, and if I were to hermetically seal the structure, the under floor would vapor up and make the place a mold pit. But with existing air flow that never happens in several years. Can a parallel to this be done below the oven if we have to go as far as dealing with the floor- just perhaps using something beside vermiculite as the insulating medium...or to set new vermiculite just on top of something...say like over an inch of gravel sitting on top of the existing base slab before replacing the brick? And even adding even one additional layer of inch thick brick over it for just a slightly raised new floor if at all?

Folks this has gone on a long time but it will be really good that we are completely informed. Whatever we do, we want to do this in the next couple of weeks and get it 'off the desk'...and onto the plate

So tally ho everyone, let's try some last rounds here please
Thanks for your consultations; we're very grateful!

Last edited by peterthewolf; 02-09-2011 at 12:56 AM.
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  #42  
Old 02-09-2011, 01:31 AM
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Default Re: Wrong dimensions - Help!!

Quote:
Originally Posted by peterthewolf View Post
? Anyone know why we've seen guys on utube breaking up glass into the under-floors of their hornos in Mexico when they build them?
Because they get confused, glass is an excellent insulator for electrical current, but not as a thermal insulator.

They see insulator and its all confirmed for them and its game over....
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  #43  
Old 02-09-2011, 04:18 AM
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Default Re: Wrong dimensions - Help!!

It is the air trapped between the pieces of broken glass that creates the insulation. In Turkey they also insulate under their oven floors with broken glass and presumably have been doing so for eons.
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  #44  
Old 02-09-2011, 09:01 AM
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Default Re: Wrong dimensions - Help!!

Lets run this by one more time.

Gravel is not insulation.
Sand is not insulation.
Broken glass is not insulation.

Maybe if I say it one more time it will break through to the front page of google.

As to the bigger issue, here's what I think. You've built a little artificial cave in the hillside. Caves are by definition cold and damp. I've spent some time thinking about how you could isolate the inside of this structure from the cold and damp, and I've not come up with anything.
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  #45  
Old 02-09-2011, 11:41 AM
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Location: Washington State USA
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Default Re: Wrong dimensions - Help!!

I've followed this thread for sometime and have written responses three times and deleted before sending, three times. Bummer to tell someone that they are just throwing good after bad and that regardless of what they do at this point they still have the proverbial "sow's ear".

But you seem determined to forge on, so in hopes of adding something constructive that I don't recall anyone suggesting: You might consider digging a curtain drain around the outside. I'm suggesting a righteous curtain drain, in fact two. One a few feet further out from the other. This should stop the lateral flow of water to the WFO from the hillside.

Now on the downside: you will be doing alot of work to install the drains. You will also make a mess of the landscaping around the WFO. All in hopes of making somewhat usable what in all honest evaluation is a pretty, yet poorly designed WFO. It won't cure the poor proportions nor wrongly positioned door, but it will probably allow the base to dry out. For the amount of effort (to say nothing of money) you could IMHO more easily tear down what is there and build something that works and that will do what it is expected to do.

As for amount of time, money and energy already spent and that you will be walking away from...ever know anyone who got divorced? This is small potatoes.

Bests,

Wiley
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  #46  
Old 02-09-2011, 12:32 PM
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Default Re: Wrong dimensions - Help!!

In every grain of vermiculite, and perlite for that matter, there are tiny little holes, so a vermicrete slab tends to act like a sponge. The crushed glass, although not being an insulator itself, would have an advantage in that the pieces of glass would not act like a sponge because they are non porous and water could drain easily through this layer between the air spaces around the glass.Perhaps this is the reason it has been used as an insulator for hundreds of years.
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  #47  
Old 02-09-2011, 10:24 PM
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Default Re: Wrong dimensions - Help!!

Quote:
Originally Posted by david s View Post
Perhaps this is the reason it has been used as an insulator for hundreds of years.
This is where one of our Engineers steps in with a graph to show is how poor a glass thermal insulator is.

I always though glass to be a very poor thermal insulator, thats why there is always cold draughts around windows in cold winters?
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  #48  
Old 02-09-2011, 11:25 PM
Peasant
 
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Default Re: Wrong dimensions - Help!!

Hey all-

Gosh, I don't mean to come off as dense or stubborn. That's not the intention. This is humbling to be sure, as we felt we had a successful history and trusted someone to follow plans...and spent the alloted budget many times over in the process.

These entries have helped in gathering information to get informed. If I had been experienced before, I would have undertaken the project myself, which would have included consulting others or outright hiring them to work alongside. Instead, I deferred to what I felt and heard was a guy's expertise. Many of you are in opposition to each other with do fix or don't fix just demo it...or try the hole above - don't try that it won't work, etc. I see value in each of your entries, because as I understand it you have all built at least your own, and possibly others as well, and also have backgrounds that would inform you. Of course it would be what it is to ask everyone to help and weigh in from your varied experience. This is (reason 1) why we have taken the position of doing step by step tries until we get it fixed - actually that the maker do so to make what has been (and *if* successful, will completely be) paid for. Second reason, we'd like to do something if it is possible and not spend it yet again. Now, that vermiculite *is* on a two inch pedestal. I'd like to exit the speculative, and drill down, see if it's wet or not. That's just a couple of bricks to replace for drilling, or four to six bricks if we get happy on it.

Thanks all for your inputs in all forms, even getting slapped around (pig's ear? eek). Gotta tear the mask off if you want to touch the soul. Anyone with insight, you are welcome here!

Finally, fixing attempts will be over the next several weeks. I'll write in when we find anything out. We can't be the only people in the world this has happened to. So if our experience - and your inputs - can help anyone else down the road, that would be great.

Peter
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  #49  
Old 02-09-2011, 11:30 PM
Peasant
 
Join Date: Oct 2010
Location: ca
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Default Re: Wrong dimensions - Help!!

Wiley-
Too bad drains are so perfectly logical. Too tight; can't get back there anymore with wire reinforced stucco and welded 1/4 inch sheet metal collage back there. Going around it from outside that would be a mess for sure. But perhaps a couple of labor days could make that mess. Ok, another option there. Thanks!

Last edited by peterthewolf; 02-09-2011 at 11:33 PM.
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  #50  
Old 02-10-2011, 12:00 AM
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Default Re: Wrong dimensions - Help!!

You are dead right brickie, but what about double glazing where there is an air space between the glass? This is how the crushed glass works as an insulating layer because of the air spaces.
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