Matt Walker Tiny Stove build in Spain

Even before I got interested in permaculture I was trying to discover ways to separate myself from dependency on commercial systems. Obviously cooking, warmth and hot water is a huge piece of self sufficiency. I think it was the exploration of economical wood burners that led me to permies.com so it's fitting that, 10 years after planning and preparing for the implementation of such a system, I post my journey here.

Background: We've got a 7m x 4m space divided down the long side into a bedroom and kitchen/living space. Tacked onto the outside wall of the living space is a bathroom that adds an extra 1.5m to the length of the building. Upstairs is my daughter's flat. The kitchen area of the living space runs along the dividing wall and the bathroom wall in an "L" shape. Originally I was going to build a rocket mass heater but couln't get it to work in the space and, most of all, could not convince my husband! He wanted something that at least looked like it belonged in a kitchen. I wanted something that burned wood efficiently as we had had experience with a wood guzzling cast iron stove before. But I will have my rocket stove! I am planning an outdoor kitchen with an oven and boil and simmer plates using rocket tech. Updates on that when I eventually get it done.
As I was unable to vent it to the outside either directly up or through a wall, I decided to knock a hole through the middle wall and run the chimney pipe over our bed so it would act like an overhead radiator. I knocked the holes in our house while my husband was in hospital-more on that later!

that looks good ,and a nice touch using the stove parts  getting them to blend into the build makes it look neat and unique, and another Walker stove for us to admire, well done---one or two more pics would really be treat for us.

That's my first post of many. I'm having trouble getting the images to load. looks like I can't select files from my google cloud storage. I'll have to download them all first. I couldn't get the drawing of the house to load as a picture, it's just a downloadable file.  I'm a techno idiot so it may take me a while.....

Hey Sarah,
thanks for starting the documentation!
Yes, it’s a bit of work to download all the photos (make sure to download them in jpeg) and then upload them again here.
On the plus side, they will be stored here and not disappear like on some photo host pages. So your posts here will stay for a long time and potentially inspire Permies in another 10 years.

Oh my! I'm looking forwards to your build story Sarah (what happened when the husband came home :O ) I love the tile top - that looks so practical. I'm still dreaming and researching here....

About 2 years agoI found an old cast iron stove that I presume was once housed in brick or clay. It was beautiful, full of history, obviously removed from an old house to make way for a more modern lifestyle. I bought it not knowing how I would use it, but determined to try. Originally I planned to put it back together as a functioning stove top and oven but realistically the oven is too small and people had warned me about the health risks of using the oven with that much corrosion. I was also worried about CO2 escaping from between the rings of the stovetop. And I really wanted a rocket stove! So inside use was out. Using it in an oudoor summer kitchen was appealing but functioning as an ordinary wood stove would produce a lot of smoke. In my area, any smoke in the summer is quickly reported and investigated so to avoid getting into trouble I abandoned that idea. Using the stove top on a J tube still remains as a future project though.
Through researching rockety stoves on Permies I came across Matt Walker's horizontal design. I really wanted an oven to bake bread in but there was no way to fit his core with secondary air feed behing my face plate without sacrificing the oven. But I gained a "conventional" look to please the family, stove top cooking, water heating and warmth.
I ummed and ahhd about leaving the stove in it's rusty state but I thought about it's appearance when it was last a functioning stove. I am sure the lady of the house would have spent many an hour cleaning and blacking it so I decided I would too.

Nancy Reading wrote:Oh my! I'm looking forwards to your build story Sarah (what happened when the husband came home :O ) I love the tile top - that looks so practical. I'm still dreaming and researching here....

Thank you Nancy for your enthusiasm. It took a long time, I've been researching rocketiness for 10 years. Having no building/fabrication experience was a really daunting factor but renovating our home showed me just how capable we all can be if we put our mind to it. I'm still not confident with metal working and welding which is why this stove with it's prefabricated elements worked for me. Scavaging and thinking outside the box will yield results. Keep dreaming BIG

I am sure the lady of the house would have spent many an hour cleaning and blacking it so I decided I would too.

Oh my - you have resurrected a thing of beauty! I hadn't realised how pretty the stove was. It is amazing what can be done with a bit of elbow grease and blacking ! We were given a large inset multifuel stove with back burner that had been sitting outside (in the salty Skye rain!) for years and that came up beautifully too. It's nice to be able to give a piece of history a new life.

My next garage sale find was the water boiler. At the time, I had no idea how to use it and I've no idea how it was employed in it's last life but it was definitely for heating water. I have no photos of it outside the stove, but it has a hidden reservoir that holds about 7L of water. The bit you can see to the right of the ceramic hob holds about 4L so a decent amount of hot water production- enough for 2 showers when fully heated. When I finalised my design and figured out how to use it as part of the stove I got a friend to weld up where it had split along the bottom seam and make it watertight.

By Nov '23 I had settled  on a walker stove. I had shown my husband various other walkers and he agreed it would look nice in our space but was still cautious about a wood stove in our small space. He suffers from terrible asthma and woodsmoke is one of his triggers.

Now I have to give a big shout out to Matt from walker stoves. He has the patience of a saint! I sent him an epistle about all my concerns, pictures of the stove front, queries about suitability, lack of fire science knowledge. You name it, I asked it -for a whole week. And he answered, even before I'd bought the plans. I didn't have the cash to bandy around so I had to be sure that what I paid for would deliver and I can tell you that, apart from the VERY detailed plans, Matt was with me every step of the way. The photos that you see some of the ones I sent to him. He was always encouraging, always gave sound advice and was always pleasant. Even after a huge  design failure (totally my fault)- see if you can spot it when we get to the 2nd to last layer- and I almost quit right there with a house full of smoke and a husband with asthma battling to cough after open heart surgery. Matt was the voice of reason enabling me to plow on.
Anyway, I bought the plans. I studied the plans, more questions for Matt. I sourced materials, more questions for Matt. Another week and I was ready to creat a mock up using waste bricks - I didn't want to build something in the house that I would have to dismantle because it was too big, or the idea in my head didn't translate, or I'd missed some major requirement that I couldn't fabricate. It helped, I had to lose a layer to reduce the overall height. It's amazing what a difference 12cm makes!
After seeing it would work, showing hubby what I intended and not getting a no but not an enthusiatic yes either I bit the bullet and bought the fire bricks for the core and the clay bricks for the shell. I carefully followed Matt's core design and I cut, numbered and dry stacked the core and sent him photos with measurements to make sure I was doing it right.

While I was pottering and figuring all this out we were still busy fixing the house a bit at a time.
Pierre had been complaning for months about feeling breathless and was having dizzy spells.He'd collapsed on the roadside 6 months prior and we think it happened in Sept/Oct when I was away as he'd feel dizzy and then find himself on the floor, we thought he'd fainted. He's always been physical, keeps fit and excercises in the heat of the day. I put it down to age and heat exhaustion and told him to be sensible.
On the 26th November he collapsed, not breathing, no pulse. I broke one of his ribs but he regained consciousness. Funny story: He had no recollection of what happened, insisted he was fine even though I told him he stopped breathing, had no pulse and he needed to be checked out. "No, no, I'm fine" he said. "You wet yourself" I said. "Get me to a hospital!" he responded.
Anyway, long story short, his aortic valve had failed and he needed valve replacement surgery. He spent the next 20 days in the local hospital as they wouldn't let him come home with his history of "fainting".
So I was able to carry on with the build relatively unmolested.
I got advice from some local cob experts on clay mortar. I did various samples like Uncle Mud suggested with various ratios of my clay soil to builders sand until I had patties that would hold up to the break, smash and crack tests. I clip my Spaniels in the summer and I had a bag full of their hair which was just the right length to add structure to my clay mortar. And I like the idea that they contributed to the build. They were ever so keen to help!
I used extruded clay beads to fill the holes in the bricks before laying the next level so the whole outside is insulated as well as the space between the back wall and all the gaps between the core and shell.
I checked the measurements for the 2ndry airfeed and made sure it would line up with the face plate when fitted, then I bought square tubing to match the size and had it cut and welded to a piece of round pipe I had lying around.

I kept building the layers but was obviously distracted as I don't have any photos of the middle layers with the steel plate that supports the core and creates the roof of the lower oven space.
Pierre went to Barcelona on the 14th Dec and was operated on the 15th. I stayed with him for 4 days and he seemed to be recovering. He has immense pain when he had to cough, and apparently a side effect of the surgery is fluid build up which caused spasmodic coughing. He was absolutely drained and feared what would happen if he had a stress induced asthma attack. I went back home and continued building with my daughter preparing the mortar and ferrying bricks. 2 days later Pierre started to go downhill, he said he was fine but he sounded so down that my daughter and I decided she should go to visit him. She stayed until he was due to come home. The arrangement was I would drive the 200km to pick them up. He was due to be discharged on the 24th Dec. I was racing to get the stove finished before he came home so that the house would be warm and cosy for his arrival.
I had clay slipped the core and hot air pathway in place and that's where I made my error. Anybody spot it?
I had knocked 2 holes through the walls of my house-one through to the bedroom and the other to the outside and fitted the chimney piping, the joints just needed sealing. That took me a whole day, the mortar between the bricks was like rock! But I got it done and all the brick dust cleaned and the bedroom dusted and mopped so no asthma triggers. I was ready to use clay slip to seal the ceramic glass hob (bought at a thrift shop for cheap) and water boiler and attach the faceplate.
And then I tripped over the broom and broke my arm.
That was at 10pm on the 23rd of Dec and I was due to drive up to Barcelona the next day. I could barely get myself to the local hospital where they confirmed I had broken it. The next day while waiting for news of Pierre's discharge I cleaned up and just placed everything where it should be so it looked complete. They were taking the train from Barcelona and I would only have to drive the 15km to the local train station.

Pierre was exhausted after the train journey so we got him home and into bed- he was impressed with the stove, thought it looked great! I took a few days off to let my arm settle and to allow the stove dry out. Near the end of Dec when Pierre was looking better and feeling cheerful I got my daughter to seal up the exhaust pipe hole with clay mortar. I had figured out how to use my arm without yelping so I sealed in the cermaic top and the water boiler with clay slip. I fitted the 2ndry air feed and attached the face plate. I had cut a piece of sheet metal for the oven door below the core and I glued some door sealing rope onto the metal frame that was screwed into the bricks. I drilled a hole each side of the door to insert pegs to hold it shut.
On the 1st of Jan I decided to do a test run. Thank goodness I closed the bedroom off and stuffed all the gaps with towels. I opened all the windows and doors. I forgot to remove the soft furnishings so I had a lot of washing to do in the days that followed....
Because this is what happened:
[youtube]https://www.youtube.com/shorts/UOqrLsPIHtQ[/youtube]
[youtube]https://youtube.com/shorts/8rK92ZzF6vo?feature=share[/youtube]

Anyway, it just shows lots of flame back and smoke pouring out. If I kept the door open I had flames, if I shut it the fire died and I had smoke. Needless to say I was deflated and disappointed and my husband was surprisingly calm. Looking back, I don't think he had the energy to do anything but commiserate and I think he was silently hoping I would pack it all  in. I was leaving on the 12th and I'd be away for 3 months.
I vented to Matt who was his ever helpful self. It was something he said that triggered an "aha" moment. He asked if the bypass was open. I mistakenly thought the bypass was only required if you had a bench attached to the stove.
So I took out the ceramic glass and removed the brickwork between the stove and the chimney to the left. I fashioned a baffle by drilling a hole through a firebrick and inserting a bit of wire. I put a self tapping screw in the chimney pipeat the point where the baffle was in the "closed" position. I stuck the glass back on and gave it a day to dry.
On the 4th of January I relit it with all the doors and windows open and no soft furnishings this time! And it worked! A bit of smoke while the core heated up but the open bypass heated the chimney creating draft quite quickly. I ran it for 4 hours before closing the bypass to ensure all moisture was driven out.

We lit it every day until I left and they kept using it until the middle of Feb. The hob gets so hot I can bring pots to the boil and shallow fry . If I let the wood in the firebox die down I can get food to simmer. The water boiler actually reaches a rolling boil and will stay warm enough without fire overnight to wash dishes in the morning. It is so easy to light when it's used every day- I can close the bypass after 10 min from startup. It radiates lovely heat into the living room and keeps the room warm overnight. The chimney does provide heat to the bedroom, we can maintain a room temp of 17`C  farthest from the chimney-the house is poorly insulated with single skin clay bricks and cement render. It feels warmer under the "radiator"One unexpected but welcome effect is the heating of the wall behind our heads. The wall gets nice and warm which helps give us more direct heat while in bed.
I don't get the flame glow through the ceramic hob that I have seen on some walker stoves.
I opened it up before the start of this last winter-late Oct. It was sooty, I'm not getting as clean a burn as I should. This may be due to the 2ndry air feed being a bit short of the opening to the 2nd burn chamber. Or it could have been from damp wood.
We've run it all this last winter late Oct-Feb and the chimney smokes a bit when we put logs in but soon clears up. We have had a problem of smokeback when the winds howl. Every now and then when there's a strong gust you hear the wind enter the stove and disrupt the flame for a few seconds. A puff of smoke and then it rights itself. I've fitted a wind cowl but I think I may need a more effective one.
All in all, we are very happy and best of all my hubby sings it's praises and is quite happy prepping wood for next winter.

Last photo of the completed stove- without me in my sling and stuff obscuring the finished article!

We were given a large inset multifuel stove with back burner that had been sitting outside (in the salty Skye rain!) for years and that came up beautifully too. It's nice to be able to give a piece of history a new life.

I would love to see your stove Nancy!

Thanks for the pie and all your encouragement Benjamin!

Wow Sarah! One hell of a job, even under normal circumstances.
And you did all that by yourself with a broken arm while your husband is in hospital? What a story.
I'm glad you shared it with us. You're an inspiration!
Next time I don't feel bold enough to try something I'll think of you building a Walker Stove with a broken arm.

I'll look into what's going on with that YouTube video tomorrow. I'm sure there's some permie that knows what's going on.

Benjamin Dinkel wrote:Wow Sarah! One hell of a job, even under normal circumstances.
And you did all that by yourself with a broken arm while your husband is in hospital? What a story.
I'm glad you shared it with us. You're an inspiration!
Next time I don't feel bold enough to try something I'll think of you building a Walker Stove with a broken arm.

I'll look into what's going on with that YouTube video tomorrow. I'm sure there's some permie that knows what's going on.

Only the last part was difficult and it kept me occupied during a time when there was nothing to do except worry. I enjoyed the journey-if not the circumstances. The videos just show what happened when the stove didn't have enough draft. Installing the baffle fixed the issue. Thank you very much for your kind words. Your work is inspiring too. I feel able to build my outside oven after seeing yours in operation. I just worked from plans, your design is an original!

That's a great build, I like that you incorporated a water tank as well.  That's one thing I didn't do on ours, although we do plan a heated bench alongside it.  Intrigued that you put the chimney base at the side, which makes it stick out into the room a whole lot less.  For use the space isn't a problem but in a small room that's a very worthwhile alteration.  

Austin Shackles wrote:That's a great build, I like that you incorporated a water tank as well.  That's one thing I didn't do on ours, although we do plan a heated bench alongside it.  Intrigued that you put the chimney base at the side, which makes it stick out into the room a whole lot less.  For use the space isn't a problem but in a small room that's a very worthwhile alteration.  

Thank you for your comment, I haven't been on permies for a long time so I only saw your build diary last week. I'm sorry I wasn't around to join the conversation.
I ran the modification past Matt and he said it would be fine. I think Matt's design is multi purpose as some folks put these in the middle of the room to heat all around it and possibly run a bench or log stack along the back. I only have 3.8m wall to wall width. With cupboards and an island work station I couldn't afford that wasted space at the back. That's the nice thing about the plan, as long as you get the core right, you can play with extra features to suit your space and lifestlye. I plan on putting a log stack frame in front of the chimney base which will hopefully dry off any dampness from my wood. I would really like to add a copper coil to the chimney thermo siphoning into a tank over the sink so I can have running hot water. I've just got to figure that bit out....

Sarah Joubert wrote:Thanks Benjamin for flagging the issue. Here goes, hopefully I do it right....

Wow! You are quite impressive! Love what you've created here. Quite an accomplished build.

Thank you Beth for your kind comment.  
This build came out much, much better than I anticipated.
I don't class myself as artistic, I'm more of a pragmatist but even I will admit that it's pretty!
I am pleased on the practical side too though, it does most of what I wanted it to do. A super hot oven would have been the cherry on top.

Benjamin Dinkel wrote:Hey Sarah,
thanks for starting the documentation!
Yes, it’s a bit of work to download all the photos (make sure to download them in jpeg) and then upload them again here.
On the plus side, they will be stored here and not disappear like on some photo host pages. So your posts here will stay for a long time and potentially inspire Permies in another 10 years.

Your encouragement started this thread and the thread got me pollinator status so the first fruits are yours! Thank you