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Summer Kitchen Renovation Part15: The Stove

From the beginning of this project, Iulia and I have had differences of opinion about a stove. You can say that the stove and these differences of opinion it represents is at the heart of this project. Because of those differences of opinion, the stove is late to the party. As a result, its placing and design were constricted by earlier choices.

The stove was NOT really a priority right now. Its chimney was. I wanted to complete the roof. The decking and water proofing layer were already in place. The chimney is a roof penetration and requires a hole! I preferred to make the hole before before putting on the shingles and then having to cut into them. And the chimney is deeply related to the stove. So … stove!

This stove is a departure from the rocket stoves I’ve been building since the beginning of my journey here at Bhudeva. The main driver for this change is that rocket stoves require attention. In our winter a rocket stove requires numerous feedings in order to keep a space comfortable for a day. 2-3 feedings are required on mild winter days, 4-5 on cold days. This implies a relationship with the stove. Iulia wanted out of this relationship.

One alternative was a batch rocket. I’ve been following batch rockets for a few years and have NOT been inclined to experiment with them. They seem to elevate the level of complexity of construction compared to a “regular rocket” … and I was not inclined to take this on.

I also encountered this article comparing rocket stoves to masonry heaters. It captured my attention but I did not explore beyond an initial reading because I did not have any plans to build a stove. As the summer kitchen renovation morphed from a conversation to a reality I started looking into it. The article led me to this “Russian Rocket” design and I’d casually spent time with it trying to understand its design. However, because of the above mentioned “differences of opinion,” I did not dig too deep … because it was not clear that I was going to design and build a stove.

When, late in the process, it became clear that I was going to build a stove, I studied it in depth. My experiences with rockets helped … but there was some new stuff I had to learn. After careful study of the stove in the article, I felt confident enough to take this effort on.

This stove, if all goes well:

  1. Is fed a large batch of wood that burns all at once.
  2. If designed and built well it should, like a rocket, burn cleanly so that little-to-no emissions remain.
  3. It uses a combination of channels through which the hot gasses can pass, and chambers in which the hot gasses can stay and stratify. The exists from the chambers are always at the bottom, so that only the cooler gasses can exit.
  4. As a result, most of the heat from the intense fire is stored in the large mass of the stove (all those bricks) and is slowly radiated into the space.
  5. It also has a “black oven.” This is like a pizza oven. The fire burns into the oven chamber, charging it with heat. Then, after the fire goes out, the oven chamber can be used for hours for cooking and baking (without a fire burning!).
  6. Unlike a rocket-mass-heater, it does NOT have an instant heating effect on the space. It provides a slow and constant radiated warmth. Depending on the thermal performance of the structure and Iulia’s climate preferences, it may be enough to feed this stove once a day.

The first thing to figure out was placement. After much deliberation and unfolding, we arrived at a location that we had not considered at all at the beginning. We were “blind” to this location because it required taking down one of the internal walls.

However, to do that, I first had to make space for all the soil that would come out of this wall so that, as with the rest of the cob, we could reuse it. So it was time for the old original door frame to finally come down:

Now, with that space available, I could take down the wall segment. In this picture half of it is down:

and here it isn’t:

… and its soil moved to where the door was, alongside all the remaining cob we are reusing:

By now I had a sense of scale of the stove-to-be. It was time to figure out its exact inner layout and footprint. Time to lay out some bricks and see what is possible:

… until I settled on to this core layout:

Now we had a foot-print and I could work on two tracks. I spent numerous evenings designing the ~30 internal layers of the stove so that we could determine roughly how many bricks (regular and fire-bricks) we would need … so Iulia could inquire about that.

Meanwhile I continued digging lower down to compensate for the height difference of the spaces the wall separated … and I made preparations for a concrete footing (sitting partially on the thin concrete floor that was unwittingly put in when I originally moved here):

… and then pouring the concrete:

Iulia found some recycled bricks … and we took delivery of 1000 pieces:

I decided to place insulation both underneath the stove and between it and the external wall behind it to reduce conductive heat loss.

We repaired (took down excess materials and filled gaps) where the old wall met the external wall … and then it was time to reconnect with brick-laying. Starting with a base layer:

… and first layers:

My past experiences cutting bricks with an angle grinder were successful but very unpleasant and messy … so much so that I avoided cutting bricks unless I really had to. This project was going to have more brick cutting than I ever did before. I practiced and got better at cutting with hand tools … and decided to (finally!) invest in a shop-vacuum … which made the work MUCH more accessible and MUCH less messy:

Meanwhile, we were searching for the metal parts that this stove requires … and most of them arrived just in time to allow the work to keep moving forward. The first was this metal grate that is embedded in the floor of the fire chamber. I cut it into three pieces, two of which went into the stove:

While waiting for the grate to arrive I continued to build up the outer skin:

… and then I could fit the grate pieces into the fire-chamber floor:

… and I could set the floor in mortar and build up the inner fire chamber:

Way back when we started this project we took apart a baking oven (that made this place in its original form a “summer kitchen”). The floor of that oven was made of large flat fire-bricks and though we could not get them out whole, we were able to salvage large parts. Now we had an opportunity to reuse them in capping the fire-chamber. We were able to assemble two layers to bridge the top of the fire-chamber made up mostly of recycled parts that were cut and fit together. Here they are dry-fit:

… and here they are in place with mortar:

We already had the fire-chamber door, but we were waiting for a ceramic band that goes around it in order to install it. The came late … but when it finally arrived it was possible to install the door:

… and to close up around it:

… now the top of the fire-chamber became the floor of the built-in bake oven … and, together with the outer skin going up around it, the oven chamber started to form:

… and finally … we could do a fitting of the bake-oven door:

… and then the oven needed a top … and we didn’t have any more nice large fire-brick slabs … so it was time for some bridging:

… and then with mortar:

… and the remaining spaces were filled out:

… and we got to work on the arch over the oven door … with an improvised attempt at carving shaping a brick fragment:

… and then closing that layer … and doing a mockup of the layout of the upper chamber … with a final location for the chimney (which is what I was really after this whole time!!!):

… and this felt like the beginning of the end … I could now count down 8, relatively simple, layers of bricks.

I started with another “floor plan” for the upper chamber and laid a 1st layer of bricks which established the structure:

… and then needed to prepare the cleanout door, it came as it set together with the fire door intended to be a door on the ash-pit, but we decided to repurpose it. I fastened it by drilling some holes and created some anchors using some good ol’fashion romanian “wire” work:

… and with that in place, we could continue moving up … until we could finally do a a first test-placement of the chimney:

… and then it was time to start capping the upper chamber:

… at this point we said goodbye to these spaces where warm air would be held, its warmth would transfer to the mass of the stove until it would be cool enough to drop to the bottom of the chamber where it would find the chimney exit.

… and at this point we got a little too excited and decided to do a test burn:

… it went partially well and partially less well … and I was a little concerned about the less well part … even though I had a feeling our experiment was premature and that the results were not indicative of the performance of the stove. We got very good flames:

… but also very good, but undesirable, smoke:

drafting = the way air and gasses flow through the stove is both simple and subtly complex! Eventually I realized that the biggest mistake was the absence of a high-enough chimney which directly affects the draft … which is critical in a masonry stove (compared to typical fire places or metal boxes with fires inside them). Indeed when I added another chimney segment things greatly improved … and when the entire chimney is installed … well … I’ll let you know how that goes 🙂

… and we moved on … completed the stove … this is me working in a tight spot to get the last bricks in:

and did a couple more test firings … still with mixed results … which worried me a bit … but only a bit because there was still some unfinished business which would affect the stove performance. Here you can see the completed stove already partially blackened from smoke from dirty burns (in an ideal clean burn there is no smoke at all since all the fuel burns either in the primary or secondary chamber):

With the chimney in place, we went up to see how it would connect to the upper part of the chimney. My working assumption was that we would just barely make the connection to the top section was wrong … we were too close. The chimney in the stove needed to move a bit. Fortunately, there was some room for “play” in its location and after a bit of dismantling (luckily much less then we imagined would be needed) we managed to shift the chimney and close the stove back up again:

We installed the bottom section of the chimney … and after some test iterations were able to install a frame extension to which the upper section would be attached.

The upper section is double-walled stainless steel with insulation. It starts with a base and a T-joint. We got it roughly located and held in place with clamps:

… and after some fiddling to get it vertically plumbed (so that the chimney would exit properly between two roof rafters … we got it installed … and Iulia is in this picture to give a sense of how big this thing is (we were surprised when all the parts were delivered … on a pallette! … they looked comfortably sized on the website!):

… and this is where we arrived today … and this is exactly where I wanted to be … ready to make a hole in the roof, install the rest of the chimney and integrate it properly into the finished roof surface.

The first bricks were laid on September 25th … so this adventure took a month!

note to self: the mortar (even taking into account the slightly too-thick mortar joints I made) … so much mortar. I counted almost 8 wheel barrows (~85 liter) of sand and 6 wheel barrows (~70 liters) of clay soil … which is … and I still find this hard to believe … just over a metric-cube (1100 liters) of material. When the materials are mixed together into a mortar they lose approximately 50% of their volume … but still … LOADS of mortar went into this.

and … to be continued 🙂

Construction Wood Framing

Summer Kitchen Renovation Part10: Going Out on Two limbs (aka: Roof Framing)

This segment of the story starts with an innocent-looking picture – a first test assembly of the homemade scaffolding … it felt sturdy but did not feel good for testing given the uneven ground next to the workshop:

Assuming the scaffolding was going to work … the next challenge was to get a ridge-beam (“technical” terms are a bit inevitable here … I will keep it simple and the pictures will hopefully provide clarity) set at the correct height and precisely aligned in the middle of the space. We built two posts to support the ridge beam and the original plan was to let them stand on the ground floor, load them up with the ridge beam and lift them up … here is that plan in action just before the “lift them up” part:

… the “lift them up” plan was never going to work … so .. plan B … we erected the two poles in place:

… and it was time to disassemble the scaffolding, bring up the parts and assemble it where we needed it … here it is right up against one of the poles with Iulia making a first climb up:

… and for some perspective on where this is going:

… and the next day … it was time to actually go up:

… and we didn’t come here for sight-seeing (though the seeing was VERY good) … we came here to build a roof … and after MUCH fiddling (measuring, cutting, fitting, adjusting, head-scratching …):

… we got a pair of rafters in place:

… and the next day we woke up fresh and a bit wiser… and greeted by this view … which reminded us that we were able to actualy get rafters up and installed:

… and we got two more pairs on:

… and then a forth:

we were really getting the hang of it … and getting somewhat “comfortable” on the scaffolding … and then we reached the edge of the building … I was anticipating this and NOT looking forward to it … but there it was … inevitably. The next pair was right at the edge and the pair after that is an overhang that extends beyond the building. How do we reach out?

We considered different ways to approach this … and in the morning before heading out to actually meet this challenge I came up with the “diving board” … it took a few iterations … but there it is:

… and Iulia testing it by taking it for a ride:

… and looking from the ground up at the naked part of the ridge beam waiting patiently for some face-to-face time with us:

… and there is scaffolding … ready to jump ship into the shark-infested waters:

… and you may ask yourself (we sure did!): how DID the scaffolding get there?

… and we brought out all the latching straps … and latched it nice and tight:

… and there it was:

At this point I said to Iulia … being jokingly serious, that I think we will not be posting these images until we finish this phase of work AND live to tell about it (=without sustaining injuries or hospitalizations). I did not want my parents to see this (they are following closely!) and worrying. Iulia laughed AND seriously agreed! So … spoiler … you are seeing these images because the story ends well!

… and once again Iulia went up for a first look:

The next day Iulia borrowed some climbing gear (which she fortunately knew how to use) … and while we were over-hanging-out we were also securely strapped:

… and the thing started to really look like a roof:

Half of the roof was done … we pulled the scaffolding back away from the edge … took away the temporary supporting posts … and there it was:

… and we ran out of charred wood. The stack of charred wood that seemed abundant … was consumed until grass was again revealed. So we set out on a late evening charring session to renew the charred stack … so we could carry on with the other half of the roof:

… the charring, amongst other things, burns through some of the resin in the recently cut wood … here is a resin-rich section continuing to burn away from the fire:

We now faced yet another new challenge … attaching a second ridge beam to the first. The space was also getting more crowded … we needed to be able to both place and move the scaffolding with the posts re-installed in their new places … and to do that we had to place one of the posts in the scaffolding:

… and get the 2nd ridge beam up and connected:

… and we were getting good at “raftering” and another four pairs went up with more ease:

… and we arrived at the other end of the building … and we needed to bring the “diving board” over to this end … but we were not quite done with it on the 1st end.

The diving board gave us access to the top part of the overhanging rafters … not to the lower “tail” part … that was overhanging along the two sides. So we split the “diving board” into two … and … I didn’t have to spend much time there … but I did have to spend some time there … and it was actually easier than working up on the scaffolding. Every time we did this we had a set routine and Iulia was handing me things as I needed them, allowing me to stay focused and steady.

During some rainy days we built more scaffolding in the workshop … another large one (like the one in the pictures above), a smaller one (pictures coming up) … and the experimental stool (my first attempt at compound angles) that snuck into the last two pictures … so we had three scales of “high” to work with.

… and the roof started looking real!

… and we moved the “diving board” to the other side …. and got to work on the last two pairs:

… and we were now as good as we were going to get at “raftering” … so they went up easiest … and the diving board came down (and probably retired … taken apart and maybe some its pieces reused … most of it was made from reused materials):

… and we got one of the collar ties in place (the horizontal section that makes a pair of rafters look like an A):

… we had to take down the large scaffolding because it was getting in the way of installing the collar ties. So the next day we completed, brought up and assembled the smaller “home edition” scaffolding:

… and after some experimentation came up with a repeatable technique. Iulia was up on the scaffolding aligning and leveling each piece while I moved around from the side to side with the stool to lock it in place:

These elements will be visible in the space so they went through more treatment before being put up. Like the other pieces, they were charred. But then they were brushed clean (with a metal brush), sanded, cleaned with a wet rag, and oiled (linseed oil). Here you can see the difference between a raw untreated charred surface (some of the raw char has been washed off by rains) and a treated, cleaned, oiled surface:

… and then … after an intense two weeks … the last piece was put in place:

… and a simple and beautiful pattern and rhythm came into being:

… and onto the next challenge … converting this roof framing into an actual roof!

Construction Wood Framing

Summer Kitchen Renovation Part9: Going Up

After charring, brushing and light sanding it was time to oil the beams:

Then … getting them up in the roof. Fortunately, they were now lighter then they were when we received them green … making them slightly more manageable! We were able to hoist one side of the beam up to one side of the wall … and then with a strap drag the other end up … and then together getting up on opposite walls … move them into place:

… and slowly but surely … the beams were up … and the structure started to feel contained again:

Meanwhile, in the background (and the shaded workshop), the first scaffolding structure was coming together:

Then … well … it was time to start framing the side walls. For this we had to spend some time considering the position of the two windows (one in each wall). This took some time, standing on the walls, looking at views, light, directions, relationship to the surrounding … some simple mockups on paper.

We started building one segment … it was fairly large and was a bit of a struggle getting up on the wall (for just the two of us):

Initially, this caused some anxiety. We were stretching our limits … of experience, physical strength and scale … this is the largest thing I’ve ever taken on … and high up! Walking along the walls became trickier when the beams went up … now with a wall segment up … it required planning and attention!

The next segment was (in some ways) easier because it was smaller.

… and in this one we tried incorporating some recycled wood … here Iulia is charring some pieces for that experiment.

We decided to do the second wall in three smaller segments instead of a large and a small segment. This is the last segment assembled on the ground:

… and then up on the wall:

… and … two walls up!

… then framing in the two window frames:

… and finally … getting into place 4 beams that will support the roof … these stick out ~85cm beyond both ends of the structure to create generous overhangs:

We already have in place (waiting to be loaded with a beam and lifted into position) two temporary poles to support the ridge-beam … until it will be held in place by the roof framing … so … we just need to complete the first scaffolding unit … and it is time to build a roof!

Cob Construction

Summer Kitchen Renovation Part7: Window, Roof, Window

After completing the “wall move” we moved to the hallway to convert the gaping hole in the wall into a window frame:

This was put off until we decided on what kind of window. We finally resolved that and I could build a frame to build in and around:

All this time the rain was unrelenting. It was raining almost every day (some days less some days more). This is a screenshot I took of the forecast during this period … basically “rain forever”:

One day this is what I found – Litsa making good use of the small pile of (now soaked and useless) straw for cob in what otherwise felt like a miserable scene:

We were having a difficult time protecting the walls (new and old) with tarps because the remains of the roof were in the way. We decided to try a different approach. Instead of trying to cover the structure with tarps (which acted as excellent water collectors that drained into the structure) we decided to remove the remaining roof elements (beams and board) so that we could drape tarps over the walls. Water would get in (and help to recycle the dried cob by soaking it) but the walls would be protected.

So on a “clear” day I went up and started pulling apart and tossing down the ~7cm layer of rough cob that was placed on top of the ceiling boards and then it was time to take off the roof. It was an unpleasant job, mud, rot, and increasingly (as the work progressed) unstable footing.

At one point it became so unsafe to be on top that we pushed off the remaining boards from the inside of the space … until only the beams were left:

The beams … oh the beams … some had scratching went into these … it took some figuring out how to approach them … but we found an approach (I am not inclined to get into … too much work just to explain the challenge). The chainsaw played a key role … and we started bringing them down:

… and we were left with a truly naked structure … felt like a ruin … with tarped walls:

Then it was back to the completing the hallway window:

… and it too became a place … with a framed view … it looks out to sunsets:

The finish level of the cob above this window became the reference level for the entire structure. This is in preparation for a concrete bond beam that will carry us up to the second level (my primary objective in navigating and prioritizing our work is to get a new roof on). So we started “shaving” and patching the rest of the structure to this level (using a simple water level). This was tedious work.

The last wall we did was the one that still had the old window in it. I was hoping to put off replacing this window until after the bond beam. But there were some questions marks that led us to give it priority. We were wondering if the ~25cm of cob above the window opening (~1.2m) would hold if we removed the window and if we could expand the opening to receive the new window frame. We carefully dug out the wall around the window … gradually released it … got it out … and were left with the rough header – some roundwood pieces that were layed across the opening. We pulled them down carefully … and got our answer:

NO! It came crashing down … at least saved us the work of slowly working it down! We were left with yet another gaping whole (and the bond beam moved a few days further into the future).

I anticipated we may need to take care of this window/wall and had already built the frame for it … here it is in fitting just before assembly:

… and just before a nut came loose in the relatively new thicknesser rendering it useless (it has since gone to service and returned yesterday):

I spend the better part of a day finishing all the other parts needed for the complete frame … including charring them … and today we were able to fit it into place. Here it is, after the last fitting test, just before it went finally went in, on the pile of rubble which was the cob that came crashing down (all of which will be re-used!):

… and here it is fit in place … plumbed and leveled:

We’ve already cobbed around the base and in the coming days will finish rebuilding the wall around it and complete the frame itself and the header which will bring us almost to the top of the wall (~2cm of cob will be required).

Cob Construction Earthbags

Summer Kitchen Renovation Part5: Moving a Cob Wall

After last year’s preparations (a bit of deconstruction, preparing for water and electricity, installing an electric post and reconnecting electricity), this spring we started renovating. I’ve been less regular about pictures so this is an overview of what we’ve been doing.

We stripped the small “porch” of its flimsy wooden covering and window. Given our slow and sometimes unpredictable work progress, we decided to keep the roof on as long as possible (so as not to leave the structure exposed to the elements). We decided to build the new external wall around the existing wood frame. Here is Iulia creating a base of cob on top of which the new earthen wall will be built.

With the frame out of the way we could decide upon the new window location (not what we thought it would be). This required putting in two new posts and removing an existing one:

Meanwhile I was experimenting with the new workshop tools (thickness-planer and table saw – maybe deserves a separate post) to see if I could build a reliably straight and correctly sized window frame (for used windows we got last year) … and I was to get a decent result. After three layers of earthbags … the frame found its place and we continued to build up around it.

We are reprocessing cob by crushing it and remoistening it. We started using the soil from last year’s deconstruction using the cob-pools we also prepared last year. When we finished that soil we started taking down the internal wall … again resuing the materials … so “moving a cob wall”:

and discovered some rotten beams … this one in particular … it had the an electric pole sticking out above it that, I’m guessing, acted as a reliable water collecter that drained above the post.

It is a clear testimony to how tolerant cob is to water (absrobs it, gets stronger with some of it while releasing the rest into the atmosphere) and how intolerant wood is (especially the basic pine we have available to us here).

We reached a point where work on the sacks was becoming uncomfortable … we were crouching and banging our heads on the beams and ceiling. So we decided to take off the roof despite god laughing at us with a 10-day forecast with plenty of rain in it. Iulia’s sister and her partner came out to visit and helped us get the tiles off:

We responded to god’s challenge with plastic tarps which are doing a reasonable job (while also efficiently pooling water). We continued to take the framing apart .. from small to large members:

Then we took off the gutters and peripheral wood sufaces. We still have a ceiling to take down over the internal room (a layer of wood boards covered with a few centimeters of cob) … and then the large beams that go across the entire structure … but that will wait for the weather to clear a bit. Meanwhile we are back to “moving the wall” and loading the cob-pools in preparation for resuming construction:

Cob Construction Floors

Earthen Floors with Sukita Reay

Sukita wrote “the book” on earth floors and it was sweet to watch her at work in this short video demonstrating the making of an earth floor:

Cob Construction

Summer Kitchen Renovation Part1: Destruction

For the past few months Iulia has been clearing out the summer kitchen in preparation for renovation. We haven’t started because I’ve been reluctant to get into this project. During this period of my reluctance we did get more clear about the general plans for the renovation. We also got a set of 4 used windows that helped us make some design choices.

Then on the weekend of the July 20th Alin came to visit with us again. I was still reluctant to start, so on the first day we cut some firewood together. His presence and ability to help with physical work did bring us to a point of “critical energy”. I walked around the cellar and found clarity about where to start. The next day we started.

The small space in the summer kitchen had a baking stove built into the rear wall. We started by taking it apart. This image was taken after the exterior (sticking out the back of the structure) part of the dome was disassembled. This the inner half of the oven dome with the metal door opened and looking into the space.

This is after Alin went inside and collapsed the chimney and other inner parts:

The base of the oven was filled with dirt, stones, broken bricks … and plenty of broken glass:

We discovered three kinds of bricks: regular fired clay bricks, unfired (we are guessing home-made) cob-bricks and large flat slabs of fire-bricks (shamota) that created the baking base. We tried to organize materials for later to re-use. We had to set aside the materials that were mixed with glass (we tried sieving but small glass parts got through). We kept the whole & semi-whole clay bricks close to the opening with the intention of reusing them to rebuild it:

Behind the pile of cob-bricks in the above picture there is a similar pile of whole clay-fired-bricks and not far away accumulated a pile of broken bricks:

That was completed on our first day of work and on the next day we moved on to breaking down some cob-wall and converting the small window into a doorway between the small space and the main space of the summer kitchen.

Alin climbed up on the roof and started taking the wall apart from the top

… and (to my surprise) the rest came down fairly quickly (even though we did not have the right tools for the task!):

By the end of this day we had an opening all the way to the ground:

During the demolition we were getting nice chunks of cob. On the first day I put a few of them in a bucket of water to see if the cob could be re-activated … and it worked beautifully. So we created a cob-bath and loaded it up with what we considered to be re-usable cob materials. I was a bit naive about the size of the bath … it filled up very quickly. We soaked it all in water and let it sit and it has become beautiful, ready to use cob:

There is already a second larger pile that we are gradually dampening to bring it closer to work-readiness:

The next day was planned to be a work day with the excavator … but life happened … so we are on hold for a while … we hope to start moving again next week.

Construction Construction Links Earthship Builders

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Cob Construction Construction Links DIY Websites


Construction Construction Links Earthship Builders

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