Napolitian style 106cm build inside a hobbit house

[crisp]

Starting to build the Dome of the Hobbit house in front of the the oven entry. I got hold of the bricks cheap they're seconds and different colours which will all be lime washed when finished. I'm going to build the domed room without supports, it's basically the same as a large pizza oven that you sit in, lol. Top centre is the pizza oven entry, to each side niches. Below right will be a fireplace, bottom left for firewood, and bottom middle storage. Don't think i'll be finished this year

[manumit]

The photos of your build are... well, they're incredible. Do you by any chance do brick work professionally? It would make me feel a lot better about my ongoing build which seems to be drifting more toward function than form.

[Alomran]

Chris: Congratulations Well done for the meticulous work. You put us to shame as the work is well detailed.

[david s]

Here's such a door. This one from our visit to Switzerland in 2010.

[crisp]

I've finally decided that the outer door will be made of ceramic fireproof glass. When fully closed you can see the whole fire without the radiating heat. If the door is totally closed, two air vents, which take air from the outside of the building feed the fire from either side at the bottom of the vent area (see recess holes in picture). The glass will sit within a U shaped frame and will be removable. There will be a counter weight the same weight as the door which hangs inside the Inside the envelope/box. It will be a bit like how a sash window works, and enables the window to stay in any elevated position due to its counter weigh https://en.wikipedia.org/wiki/Sash_windowt. All this will be will be removable for servicing

[thevance53@gmail.com]

I just started one under introductions and just started posting. Keep going back and posting to keep it current and it will show in the new posts area.

[crisp]

Hi,

My post is under 'forum guidelines', I'm not sure whether it should be under this? How do I create a "My Build" thread?

[crisp]

Managed to get the vent/chimney area done today. The holes on the sides are for vents supplying air from the outside of the building, this will help the draw. The sliding door will be built between the chimney/vent area and the final front arch which isn't built yet. Onwards and upwards with the vent transition to the chimney.

[crisp]

David,

Thanks for your advise. I have also build a wood fired lime kiln which burns for three days constantly reaching temperatures between 800 -1000 degrees centigrade, you might be interested in the pictures?. This kiln burns 1 cubic meter of limestone. I used a checker plated door with a baffle plate to stop radiating heat. This door buckled after couple of days burning so I know what you are talking about. Inside the kiln I used a heavy duty cast iron road drain as the grate and air intake, after three day of burning even this cast iron grate melted. Obviously a pizza oven does not need to reach these temperatures, but I will try and get my hands on cast iron for the door. As for sealing the door, the will door only be used to stop radiating heat into the room, so the door does not have to be totally sealed. Yes I will have to rethink servicing the door and making it accessible for any repair.

[david s]

Chris,

I've built a number of kilns and fired many more and while kilns operate at higher temperatures than ovens the principles are the same. Steel is compatible with concrete for civil projects like buildings and bridges, but to combine it with refractory materials and rapid heat rise creates problems. Primarily, the huge difference in thermal conductivity between steel and refractory means uneven expansion as the heat rushes to the more thermally conductive material (steel) resulting in stress on the refractory. Secondly, heat accelerates corrosion and particularly if it is thin, does not take too long before it needs replacement. The problem with kilns is even greater because of the sulphuric fumes emitted from the clay body. I've seen so many kiln fail because of the door design where mild steel has been used rather than stainless, doors dropping, hinges, bolts and screws rusted. Beware of galvanised steel as poisonous fumes are emitted from the zinc coating.I think sealing of your guillotine style door will be a challenge. Italian ovens often sealed around their doors with some bread dough, crude but extremely simple and effective.

Your design may well work beautifully (and I hope it does), however, if you have problems three years down the track, try to build it now, in such a way that it can be easily serviced.

[crisp]

Yes Chris, the more I think about it, the more I like the drop-down door. If the groove is in the outside vent area it won't get much soot or creosote and since you're thinking of a counter weighted, chain lift/lock system, you certainly aren't going to get lots of black on your hands moving the door up/down, What would be fun to do is check with your local schools and see if there are some art students that like to work with metal,,,I bet they could really make your drop down door quite the show piece for the oven (as I bet you could--based on the pictures we've seen of your work!).

I really like that you are planning to have adequate air venting from the outside so the fire will not pull air (much) in from the room. Make sure that you cover these vents with hardware cloth/screen to make sure you don't have unwanted guests or have live coals drop down under your structure . Would these vents be built with some sort of closure? So they could actually be used control/dampen the fire as needed.

I'm going to be out of Internet service (or have very limited connections) for the next three or four weeks...I'm really looking forward to what you come up with, so don't think I'm ignoring you. We were in Barcelona last year and I agree that Gaudi's work in Barcelona is amazing (as is David's ). Since I've joined this forum, I find myself more and more fascinated with any architecture that has features of an arch or dome...I don't know if I should admit that since I got my Masters degree (40 years ago!) as a fisheries biologist.

Hi Mike,

I'm going to go for fabricating the door myself. I think i'll make a steel rectangular box/envelope, which I will build in-between the chimney/vent and the rooms facade and positioned above the arch. A "U" shaped metal channel from the box/envelope down to the hearth floor will be built between the Vent /chimney area and the rooms brick facade providing a slot for the door to slide in. The door can then be hoisted up into this box/envelope and not be seen. I'll have to work out some sort of simple hoist system which won't need any maintenance (once built in I won't be able to get it out again). I think I'll also cut out for a glass window in the door, so if closed you'll still see the fire.
I found these closable vents which I can build in either side at the bottom of the vent area.http://josefdavidssons.se/produkt/ac...-2-en/?lang=en
All this will take a while to fabricate, but it means that I can continue with my vent chimney construction due to the door being mounted between this and the rooms facade. Thanks to your advise about soot, it made me rethink putting the vent between the rooms facade and chimney/vent. Really grateful for your input Thanks.

Chris

[SableSprings]

Yes Chris, the more I think about it, the more I like the drop-down door. If the groove is in the outside vent area it won't get much soot or creosote and since you're thinking of a counter weighted, chain lift/lock system, you certainly aren't going to get lots of black on your hands moving the door up/down, What would be fun to do is check with your local schools and see if there are some art students that like to work with metal,,,I bet they could really make your drop down door quite the show piece for the oven (as I bet you could--based on the pictures we've seen of your work!).

I really like that you are planning to have adequate air venting from the outside so the fire will not pull air (much) in from the room. Make sure that you cover these vents with hardware cloth/screen to make sure you don't have unwanted guests or have live coals drop down under your structure . Would these vents be built with some sort of closure? So they could actually be used control/dampen the fire as needed.

I'm going to be out of Internet service (or have very limited connections) for the next three or four weeks...I'm really looking forward to what you come up with, so don't think I'm ignoring you. We were in Barcelona last year and I agree that Gaudi's work in Barcelona is amazing (as is David's ). Since I've joined this forum, I find myself more and more fascinated with any architecture that has features of an arch or dome...I don't know if I should admit that since I got my Masters degree (40 years ago!) as a fisheries biologist.

[crisp]

Hi David,

Thanks for your interest, I have alway been interested in arches and domes. I have visited Gaudi's architecture in Barcelona, it's inspiring, just like your shelter/canopy, thats so cool.

Masonry is only stable when all the units are in compression; any tensile forces result in instability. That is why modern concrete buildings have reinforced steel within; concrete has little tensile strength without it. Before cement/concrete was invented (1824) all masonry buildings had to be built in compression. I'm babbling on a bit here sorry.

I have built in a steel bracing around where the dome springs from. Also because the outer facade continues plumb and the interior brickwork arches inwards, the gap between increases with height, this is called "the haunch". By loading the haunch with masonry, the invisible line of thrust is bent downwards and through the wall. Most vaulted cathedrals have loaded haunches to bend the line of thrust down a pillar The haunch is basically a ballast. I'm not very good at explaining this but this does http://www.earth-auroville.com/stability_notions_en.php

The whole Hobbit house is built with lime mortar, I slake quicklime with the aggregate, a "hot mix". There is also a quicklime concrete between the interior brickwork and the granite facade. The stainless steel bracing is within this concrete. Both walls are also tied together with stainless steel ties. Nearly the whole project, including the oven is built without cement; there is only a cement/concrete foundation both under the Hobbit house and under the oven.

Chris

[david s]

Thanks for the compliments Chris.
Because heat is involved, which tends to compromise joints, bracing or buttressing is more of an issue for a kiln or oven. However it also applies to a lesser extent for buildings. Have you considered the need for either for your hobbit structure because straight walls support the domed roof.

[crisp]

I've used rock wool on a couple of ovens and it is placed directly against the inner dome. I can't remember the rating of the stuff but pretty sure it was not much less than ceramic blanket, so I'm sure it's ok to lay it directly over the brick.Remember that the outside temperature of your inner bricks will be considerably lower than the inner face. I found however the stuff was a bitch to cut compared to ceramic fibre blanket, was far less dense so hard to vermicrete up to and it is also way more water absorbent than ceramic fibre blanket, so I now don't use it although it's a little cheaper.

I hope you have a decent flue diameter planned for the oven because front fluid ovens are notorious for smoke out the front at start up. Being in a small hobbit house full of smoke could be unpleasant. When in Pompeii I noticed quite a few small central flued ovens in private homes (unlike the larger front flued ones in the bakeries). I presumed this was because people didn't want their houses full of smoke, while the bakers oven probably never cooled down.

If you're interested in catenary arches you may be interested in this. It is an elaborate although I think elegant shelter for my kiln.
#32

Hi David,

Thanks for your advise, and nice to know Rockwool can be used and is efficient. I've already got lots of Rockwool so I'd be daft not to use it, and ceramic blanket is really expensive here in Norway.
I was thinking of building in two air vents, on the bottom of each side of the vent/chimney area with ducts taking the air supply from the outside of the building. This will help the draw of the chimney and not steal air from inside the room. I thought of an 8 inch (20cm) flue which I might just build with bricks and no liner. Years ago masons parged the chimneys with clay mortar mix as they built, reaching in and rendering the sides.

Love the shelter, what a fantastic Idea. A friend of mine built a large cabin cruiser boat out of concrete similar to this. Your structure is totally stable as it is a catenary. Gaudi built many thin walled arched structures which can only be achieved using a catenary arch. Most people seem to have the idea that all arches and domes are self supporting. Not all of them are without additional buttressing and loads. This is why I used a harness.

Chris