Wrong dimensions - Help!!

[david s]

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.

[brickie in oz]

Re: Wrong dimensions - Help!!

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?

[peterthewolf]

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

[peterthewolf]

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!

[david s]

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.

[brickie in oz]

Re: Wrong dimensions - Help!!

but what about double glazing where there is an air space between the glass?

Air SPACE, space being the operative word.
Not, loads of jumbled up shards of glass all touching and connecting and leaching heat to the next shard of glass.

You may as well fill the space with munched up bricks and say its insulating.

[peterthewolf]

Re: Wrong dimensions - Help!!

David, Brickie-
Forgive this. Learning the process here as we go. Pull up the floor: Then glass, draining gravel, whatever: To build a pedestal of draining material an inch or two up on top of the existing 2 inch slab, then a thin (membrane) layer of mortar, then above it, vermiculite with brick on that...are you saying that with the several inches of drainage this could be ok? That means of course, ending up with a floor that is one brick thickness higher than now, to accomodate the draining layer on the existing slab below, but ok then. Is this an option?

[david s]

Re: Wrong dimensions - Help!!

yes, I think that's what I'd try if it's easier than starting from scratch.

Brickie, if you add air to any material it becomes less dense and hence a better insulator. Hebel or AAC is a good example of this, it's made of concrete which is a poor insulator, but when full of air it becomes less dense (about a third the weight) and in turn becomes quite a good insulator.

[brickie in oz]

Re: Wrong dimensions - Help!!

Peter, if it was me, and Ive been avoiding saying this, but I would cut my losses and do it all again properly, as I have done with my own oven.
http://www.fornobravo.com/forum/f44/...two-15241.html

David, we agree to disagree..

[lwood]

Re: Wrong dimensions - Help!!

Peter, is there any way to excavate under the oven floor? If you can create an air space under the oven you might eliminate much of your problem. Let's try to save this thing. Where in Ca are you? What is the oven floor sitting on? Is the slab directly on the ground? What are the layers of masonry you have now, starting at the ground? Hopefully a steel reinforced slab of concrete, some vermiculite/concrete insulation, etc. Tell us, in detail, what all those layers are from the ground to the oven cooking surface, including thickness measurements. If the existing slab can support the rest of the oven, you can excavate just enough to build a structure underneath it. No guarantees about cracks and how easy it will be, but you can save most of the structure.

I'm afraid that as long as you are in direct contact with the ground, you will have a problem. And It appears you have it coming from three sides of the oven. The quick fix you are looking for is just not there. It's very difficult to really understand this issue remotely. Maybe there is an easier way, but from here it's hard to see it. Have you asked anyone else to look at the oven? Like an expert. Might try that.

I would do all the investigating you need to do to convince yourself of what to do. Drill holes, look at the vermiculite, whatever. Then if you are interested in trying the excavation I am proposing, I am happy to walk you through it, as well as many others on this site, I'm sure. You know Peter, the advice you get on this site is worth just exactly what you paid for it...nothing, unless you use it.

[roobqn]

Re: Wrong dimensions - Help!!

Yes, we built it into the hill. We dug back, leveled, left space at the corners about one foot, and where the dome bulges out to meet flat hill angles, only a few inches. We stuccoed the hill cuts onto wire mesh and left no exposed dirt first. We mortared that ground around with a slight flow out toward each front side of the whole structure to channel water. Look for a little black circle at your kneecap height on the right side of the picture. That's a short piece of black 3 inch flex drain through the half wall, so rain water can exit forward and away. Yes, this hillside holds and dispenses a tremendous amount of water in Winter. The cement bulge of ground that you can see at the base of the whole structure in front is a 1 foot wide open swale that runs all around the base of the hill to carry water away in the rains. The fireplace floor is bridged over it. From both seepage and real flow from gopher sized holes punched in the stucco retaining wall all along the hill into the swale, much water can flow out from that hill. What on earth (pun) can we do - short of demo-ing and lifting up a *new* oven to counter absorption and heat sinking??

Peter

This sounds like the base is either already suspended off the ground OR at least partially dug out and a starting point to excavate further. Not sure which though.

The rest makes it sound as some excavating was done around the oven, but only to the point of the floor. Can it be dug out all the way around and the resulting cut out be replaced with a new retaining wall on all three sides? This would seperate the oven from the hillside.

In another post however, you said you sent the mason a letter that said in effect fix the oven as per the plans or loose the rest of the money. I would see what comes of that. Let him come out on his dime and follow the plans to the T. In effect making him demo the entire thing and rebuilding, that includes the base and sides. Unfortunetly that may cause him to walk away from the rest of the money leaving you where you are now. Might be a blessing.

[JAG]

Re: Wrong dimensions - Help!!

Just for the record. FWIW.

Note the conductivity


glass-1.05
glass window is-.95
vermiculite -058
Portland cement-.029


Thermal Conductivity of some common Materials


JG

[peterthewolf]

Re: Wrong dimensions - Help!!

Hey- now we're talking! Roobqun, lwood thanks. I'll clarify those specs here, and just took some photos. Brickie hang in there with me. Because we did spend a ton, and I prefer not to go through the hassle of getting the money back or spending it again, I would like to see if we could discover our way out if it is possible. So thanks for your patience in this process. If it ends up a failure, at least we can say we tried.

Brickie would you mind once more if I send you photos to post? It's not working from here. I just took photos of the slab on which the oven sits (back corners stick out so you can see it), of the drainage for surface and subsurface water, and of the narrow channel that is between the dome and the hillside that we dug out and stucco'd for view of the retaining wall and space.

Details: Yes, the slab is reinforced, with rebar. The ground it sits on is sandy clay: a soft moisture conducting sandstone which can be wet in winter. It's not the easiest thing to dig, but a pick takes out chunks per stroke. It is almost rock hard in summer. The oven is not "into" the hillside - no side contact. That stucco around it with the sheet metal decoration is essentially a retaining wall on 3 sides. We dug an area larger than what the whole oven would occupy. Then we left a "slot" around the oven like a horseshoe for any water on the surface to travel around downgrade to the drainage that is below the whole structure.

The slab is two inches thick from ground up, sitting on that clay. The vermiculite is 4 inches thick, sitting on top of the slab. That all was done in a 2x6 mold. I think it was half an inch of mortar, just for brick setting, on top of that, onto which the brick floor was set. The bricks are set flat, so the brick floor is one brick thickness, about 2.5 inches, pushed together without mortar between them on the mortar bed. So there (are) at least two inches between water on or in the ground, and the vermiculite.

Is vermiculite *that* absorbent, that it would suck water vertically upward from the flat surface of the two inch slab beneath it and wick itself upward to saturation? It was 5 parts vermiculite and one part portland. It may have been 4:1.

It appears to me that the brick dome also began (on top of) that slab, and built upward from there. In the pictures you'll see that the rock dome goes lower and touches the narrow water draining channel below, but that rock is pretty non porous, and even if slightly so only small contact points from rock to rock are there. But it's the setting grout - a lot of it between the rocks - that is porous, and that goes down. I don't believe any of it sits just on earth. If so, only the mortar between external rocks touches at the bottom, and that would be only where (if) it is not on the slab.

As you can see from the paint roller handle set into the channel for size reference, there is not room to get in there to excavate further out into the hill for drains. For that, we'd have to go outside, around it, as it is all stucco/wire...and a fun sheet metal sculpture that is *all* welded together. So we're holding on that idea so far but not out of the question to hire a couple of labor folks to dig a body-wide channel around that and down a little.

Yes, roobqn we did send a letter, saying please fix it to the point that it works, and burns efficiently like ovens in the plans do (average feedback I am getting is 3 to 8 wrist sized sticks brings it up, and only a few sticks maintains it hot - all with the door open). Certainly this guy is capable of doing these things - according to our directions since it has now been necessary to go back and do this research and consulting. If he is unwilling or unable to accomplish the result after our time limit is reached, then we will use remaining funds to get someone else. Judging by our last face to face conversation, we do not know if he will be willing, or will walk. Que sera sera. We have given a couple of weeks, which is good for brainstorming.

Last, I could see somehow *drilling* beneath the slab horizontally through the brick face of the low fireplace to get under the slab, but it would be an impossible *dig* to get back under there. The only way to get under that slab the way it is set back into the hillside is straight back from the patio, and at that it would be about 7 feet back through an opening that could only be say, 1 x 1.5 feet through the back of the fireplace which sits beneath the oven's cooling shelf.

lwood, we are in Sebastopol, a hour North of the Golden Gate Bridge, near Santa Rosa. Are any of you guys local?

[brickie in oz]

Re: Wrong dimensions - Help!!

Brickie would you mind once more if I send you photos to post?

Sure, go ahead.

[Wiley]

Re: Wrong dimensions - Help!!

JAG, Thanks for posting the link.

If one were taking examples more akin to what we are dealing with in our finished WFOs the "cement" listing is perhaps the wrong one to take. I would think the the "concrete, stone" at 1.7 one might be more accurate to what we have in our WFOs. The listing for cement is a bit ambiguous (IMHO) in it doesn't state the condition of the cement, as in: "cement , powdered, dry, loose" or "cement, compressed to solid mass" or listing a moisture content of cement if they meant after it has been mixed with water and cured to a solid mass (and that would bring into all sorts of variables such as how much water when mixed and the moisture content of cured cement). One would think and expect that the latter (mixed solid mass or compressed to a solid mass) would have a thermal conductivity closer to the listing for concrete.

The listing for "concrete, stone" at 1.7 is closer to the listing for "cement, mortar" at 1.73.

bests,
Wiley