Build a Rocket Stove from Concrete Blocks

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A concrete block rocket stove is easy to make. Consider this method when you’re ready to learn build a rocket stove for outdoor cooking.

concrete block rocket stove with flame showing

The cookstove is almost as old as the campfire, and not much newer than the invention of fire itself. Needless to say, it’s been around for a long time, with very little change. Even in today’s world, many people on this earth still cook food over an open fire, just as our ancestors once did.

Recent innovations have harnessed gas and electricity to cook our food, but what about the original fuel source: wood? The wood cookstove has largely gone out of fashion in most developed nations in favor of gas or electric ranges, but is there a more renewable resource than wood? Some would argue not. So why not try to imagine a truly efficient cookstove that utilizes a renewable fuel source like wood? Enter the rocket stove design.

What is a Rocket Stove?

It was originally developed in the 1980’s by Ianto Evans and Larry Winiarski of Aprovecho Research Center, an organization that works on designs for cookstoves that are to be used in developing countries.

The rocket stove uses small diameter wood which is burned in a simple combustion chamber leading to an insulated vertical chimney, atop which the food is heated and cooked. This design burns so efficiently that it ensures almost complete combustion prior to the flames reaching the cooking surface, so there is virtually no smoke.

Why Build a Rocket Stove?

A home-built concrete block rocket stove effectively satisfies all of the practical criteria required, and at the same time saves money and fuel. Because they are so fuel efficient, very little wood is used. This means that the fuel can be sticks and twigs from prunings or dead fall, rather than large, older growth trees.

This versatility and ability to burn almost any size wood greatly increases the sustainability of fuel use and availability, while also minimizing the environmental impact. To put it simply, it’s an easy to build, easy to use, clean burning cooking device that uses minimal fuel.

Sound too good to be true?

Well, you do have to learn to light a fire and keep it tended, so there is some additional work involved as opposed to just turning a knob. That said, once you get it going, it’s pretty easy to keep the fire lit.

silver saucepan on a rocket stove

How to Build a Concrete Block Rocket Stove

The design is simple, but the real breakthrough idea is that these rocket stoves can be made from almost anything. Imagine on one hand a very small stove made from a few tin cans fitted together, simple and portable. (In this case, we’ll use concrete blocks.)

Then, on the other hand, think of a large, permanent cob stove capable of boiling water in enormous stock pots and heating your house at the same time (via a rocket mass heater). Rocket stove design lets you, the builder, construct a stove that fits your needs, space, and budget.

Here I will show you how to build a simple concrete block rocket stove with materials that are easy to find and inexpensive.

This is what you will need:

  • 3 concrete blocks
  • 1 H shaped block, OR two 8″ x 16″ pavers and one brick
  • 8″ X 16″ pavers, optional as needed (for a base)
  • A grill or old burner of some sort
concrete pavers in the ground

Step 1: If you do not have a flat cement surface to build a rocket stove on, you may need a couple of pavers to serve as a base for the concrete blocks. That is what is shown above.

building a concrete block rocket stove

Step 2: Place one concrete block horizontally and another one vertically in front of it. I’ve seen other guides that put the horizontal block rotated the other direction, with the holes going from side to side. You’ll get a deeper fire box by doing it this way. Try both ways to see what works best for you.

pavers and a red brick from above

Step 3: If you have an H block, place it on top of the horizontal concrete block. We had trouble finding an H block, but 2 pavers and a brick worked just fine.

finished concrete block rocket stove

Step 4: Place the last concrete block on top of the H block (or pavers and brick). Once you have the rocket stove lit, put a grill, grate or old burner on top of the stove as needed for a cooking surface.

fire burning in rocket stove

How to light a concrete block rocket stove

It’s important to get the fire chamber lit and going well before adding more fuel. Fill the first hole in the top with newspaper, cardboard, very small (dry) kindling, and any fire starting material you may have. Light it, and keep adding small kindling until the fire is going really well.

wood stacked inside a rocket stove

Then feed small split logs into the hole on the front of the stove. These can be about the size that is usually regarded as kindling for a regular fire. Add two or so at a time. Every so often, push them in a bit so that they continue to burn.

A rocket stove made of concrete blocks with kindling in upper cell.

It really is as simple as that! What I love so much about this method of building a rocket stove is that it’s extremely simple to build with materials that are readily available. It can also be broken down and moved on a moments notice if need be.

Rocket stove technology also allows you to have some independence from the electrical grid in the event of a power outage. Need to boil some water or heat up a can of soup? No problem!

A concrete block rocket stove is definitely something we should all consider building on our path to self sufficiency and emergency preparedness.

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Cheers!

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Meet the Author

Colleen Codekas

Colleen (and her hubby behind the scenes, Joel) run the blog Grow Forage Cook Ferment, a website that teaches about all types of homesteading endeavors, particularly related to food, herbalism, permaculture, health and self sufficiency. She loves growing and foraging for herbs and other plants, making herbal salves, cooking food from scratch, and making mead (honey wine).

30 comments… add one
  • Dean Cattell Feb 11, 2016, 6:57 pm

    Do you need to put a grate between the H Block and the top cinder block to stop the fuel from dropping into the bottom cinder block?
    Thanks

    • Colleen Codekas Feb 12, 2016, 1:44 pm

      Hi Dean. No, the grate is just used as a cooking surface. It’s ok for the fuel to go into the bottom cinder block. If you want you can turn the bottom cinder block on it’s side so that the fuel doesn’t go into it, but it’s usually not a problem. Either way, you definitely don’t want anything between the H block and the top block, as that is the space where you start and fuel the fire. Hope that makes sense!

  • Shaz Feb 11, 2016, 11:41 pm

    Hi there, thanks for this easy tutorial. I must say, with some of the pictures it’s not clear if it’s a top view or a side view?

    • Marie Raven Feb 17, 2018, 10:00 pm

      I’m having the same problem, myself. Maybe if we got the material and set it up as described it would be obvious.

  • James Davis Feb 14, 2016, 3:41 am

    I use to cook manytimes in the woods as a kid out camping. I was raised on a farm! What you show is very interesting to me!

  • Gary Mar 12, 2016, 5:25 am

    Doesn’t the heat of the fire destroy the cinder blocks?

    • Durwood M. Dugger May 8, 2019, 10:33 am

      Yes. Especially, if they are new and or damp when you use it. I have had numerous concrete block fire pits and in everyone after repeated use the blocks cracked and crumbled to chunks. Nice idea – very wrong material for implimentation.

      • Kris Bordessa May 11, 2019, 12:24 pm

        There’s a difference between cinder blocks and concrete blocks. Use concrete blocks.

  • Jason Roland Jun 30, 2016, 7:15 am

    I love this idea for outdoors or camping. Cinder blocks will never run out of uses.

  • Stacie Aug 4, 2016, 3:22 am

    We made a rocket stove out of a couple steel rims. We use it during camping and there truly is very little smoke. It burns hot and puts out a ton of heat even 4′ away.

    • Nora Oct 14, 2018, 11:41 am

      How did you do this?

  • Colleen Sep 13, 2016, 1:18 am

    Now THAT is entirely helpful. I’m going off grid soon, and I had heard of any number of ways to build this – including some very expensive options (which kind of minimalizes the idea of going off grid, doesn’t it?). This is simple enough for a clod like me to follow, and waaaay better than any hazardous material that was suggested. Thanks!

  • Maggie Oct 28, 2016, 8:21 am

    There must be something I’m missing. Is there a reason not to do the following? Leave off the bottom block that is horizontal and put the “H” block or equivalent right on the ground/paver and then feed the fuel through the bottom hole of the vertical cinder block. Is there a need for the space below the fuel feed area?

  • Doug Hargett Oct 28, 2016, 5:34 pm

    What is the purpose of the 2nd chamber (furthest from the fuel feed area) of the horizontal block? Wouldn’t the H block keep anything from entering the 2nd half of the horizontal block? Also, what keeps the pavers from falling over, or the brick?

  • StaxSunChess Feb 18, 2017, 7:38 am

    The 8″ x 16″ concrete pieces shown in this article are not pavers. They are actually called “caps” and are typically used as a finish layer at the top of a cinder block wall.

    The necessity for the correct terminology would come into play during the ordering process.

  • Ben May 10, 2017, 6:50 am

    So if you use pavers and a brick for that 2nd layer, how do you keep them from falling off? And how do you go about cleaning out the stove, just take it back apart and brush it away?

  • Bob Bigelow Jul 6, 2017, 5:51 am

    If you can’t find the “H” block, and don’t trust the caps and brick arrangement, try chipping out one end of a regular block. It’s a tricky process…to chip out the end without breaking off the side, but can be done. Wear eye protection!! And keep your mouth shut..concrete tastes terrible. Patience is the key.

    • Alan Mar 9, 2018, 3:51 pm

      Not difficult to cut with a 4″ grinder and a masonry disk.

  • Norm Hotchkiss Jul 6, 2017, 6:01 am

    I like that you can build several of these side by side. It’s a little awkward with keeping the fires going, but you could cook for many people this way.

  • Kitty Jul 6, 2017, 10:03 am

    I can’t seem to wrap my mind around this and I think it’s because you only show your photos straight on rather than from the side angle as well. I can’t figure out what your using or how to place the cinder blocks or whatever they are . please consider adding a photo of all of the elements laid out and one of the whole set up from the side in order to give a better perspective. the “building blocks photo might have each type numbered and the side version might include numbers on each block referencing the first. I can’t imagine how you’re placing these to make a stove. or where you’re putting in the fuel. maybe it’s just me but I need more help. LOL

    • Saneinaninsaneworld Apr 28, 2019, 4:43 pm

      There are several YouTube videos that provide a good understanding on the components, their functions and continuous video off ones being built with many mediums and styles. Good luck

  • Kate Dvorak Oct 13, 2017, 7:14 am

    I could not get the cinder block to work. Had to use pavers and brick, but it just didn’t draw and couldn’t keep fire in box going never mind adding. bought some kindling even. I have to BBQ grill so was hoping to use this. I wonder what’s wrong?

    • Kris Bordessa Nov 14, 2017, 8:17 am

      Sometimes these things take practice!

  • Jockosi Dec 15, 2018, 11:19 am

    Just one proper drawing of this would make it so clear! please can you do that?

    • Kris Bordessa Dec 19, 2018, 7:52 am

      I’ll put that on my list of things to consider!

  • Cheryl Turnley Mar 22, 2019, 5:16 pm

    Thank you for your excellent directions. I’ve always been dumbfounded after reading directions for using cans and it seemed like alot of cutting and fitting just to try something that made no sense to me.
    After reading these directions I grabbed a some cinder blocks, a couple of short pavers, and a brick. I had one flipped the wrong way at first but without just a few minutes I had me a rocket stove and I am one happy camper!

  • Rob Apr 19, 2019, 11:58 am

    The air is drawn up the end of bottom block to feed fire.

  • Peter Feb 15, 2020, 6:29 pm

    I built this. It worked well, but after single long burn, with multiple fuel feedings, the cinder blocks fractured at the point of highest heat.

    I’d have to say that until this problem is fixed, I would not rely upon this design as a survival stove option.

    • Kris Bordessa Feb 18, 2020, 6:17 pm

      Did you use *concrete blocks or *cinder blocks?

  • Greg May 24, 2020, 8:54 am

    My fellow Cub- and Boy Scouts and I were building these in the late 60’s – early 70’s. They were based on a Cherokee method with rocks and riverbank clay. Occassional we’d camp near an old farmstead ruin, and use leftover bricks….

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