DIY dry toilet system for 8 Euros or $11 - Part 2 The Cabin

It's been about two and a half years since we set up our dry toilet system in the garden and it was only the other day when I was looking through the Green Lever archive that I realised we had not written a post about the cabin and the seats. These will be long posts because there is a lot to share, so without further delay here is the first, the design, construction and assembly of the cabin (pictured below).


We've long been talking about building our own Eco-house. Much of the work we've done in restoring the 300 year old Longère in which we now live, has been experimental in trying out more environmentally-friendly techniques and using ecological materials. Our Eco-house is to be completely off-the-grid including being autonomous with our own water supply. This being the case, reducing water consumption is essential and the biggest consumer of our water is the flush toilet. We also decided to have an extra liquids only toilet in the house and so, except for offering the choice to visitors, our flush toilet became totally redundant. In Setting up a dry toilet, which we wrote back in July 2012, we posted our water bills, showing how our  consumption and thus costs, dropped by two thirds once we stopped flushing. The extra added bonus, apart from feeling a lot less wasteful, is that we can now grow beautiful flowers in what was once some very poor soil!

Design criteria for the whole system

We decided that the toilet would be located in the garden because it would be easier to empty the contents into the composting bin and also, as we spend most of our time in the garden or workshops, muddy boots would not be a problem. Thus, we needed a cabin to house the toilet, a seat and a composting bin. I also wanted a design that could be made in and transported from the workshop. Wherever the intended siting, it is always better to have something which can be fabricated inside in comfort, rather than outside in the rain. It also makes for a practical design if you want to use this system for somewhere such as; your allotment, social garden, a field or even set up a business making them for others.

The seat 
For ease of composting we decided to separate liquid and solid waste at source, hence a dual seat arrangement seemed to fit the bill. Beneath each seat would be bucket. The solid waste would be covered with sawdust after each visit and emptied into the composting bin when full. The contents of the liquid bucket would be diluted with rain water to be distributed around plants in the garden.
N.B. this latter has recently been updated in order to accommodate people who live in extreme climates and the post which covers this update can be found here: Composting urine using a straw bale
The cabin
Tall enough to stand up in, the cabin had to be wide enough to accommodate the dual seat, with enough 'leg-room' for comfort. It needed to offer privacy and protection from the elements and had to be easily transportable from the workshop to its site in the garden.

The composting bin 
For this we decided to use the same successful design that I came up with some time ago for garden/vegetable waste i.e. horizontal sliding wall planks that allow for ease of access and very easy to transport for assembly on site. For its design and construction see my post: Untreated Pallet Wood Compost Bin

Fabrication of the Cabin

I decided the cabin would comprise a modified pallet base that would be placed on a stone chipping foundation. Corner posts would be fitted to which the framing for the two side walls and rear wall would be secured. The walls for these would be vertical pallet planks slid between the frame wood (very much like the compost bin). On the front elevation would be a pre-assembled panel and a door. Cross-bracing connecting the diagonally opposite corner posts at the top would stiffen the structure and the whole would be covered with a pitched roof .

On one of my regular pallet-collection runs I obtained a non-standard sized pallet 100cm x 120cm this was perfect for the cabin base, the 100cm width was enough to fit the double seat. The first step was to fill in the gaps between the existing pallet planks with planks of the same thickness so as to make an even floor.

Turning the pallet over I then attached planking around the edge of the pallet such that about 2cm of wood protruded all the way around the pallet perimeter. 

Each corner post was made by screwing together two 210cm long pallet planks so they formed an 'L'-shape which would fit against the two outward-facing sides of the pallet's corner blocks. These posts rested on the 2cm protruding wood and were screwed to the pallet blocks. Thus all of the vertical weight of the posts, additional wall framing and roof structure, was supported by the protruding wood attached to the underside of the pallet. The screws merely stopped them from moving around. 

I cut planking and fitted it around the pallet base so as to prevent any openings that a small hen or pigeon would find 'interesting' once the cabin was erected in the garden. This planking furnished the edge upon which the wall planks would rest. 

Planks were cut to length and screwed to the outside faces so as to connect horizontally the corner posts. Six planks were required for each side wall and the rear wall, They would form the retaining rails when the wall planks were slid into place.

The vertical position of the retaining rails were; near to the 'floor', at the top of the corner posts and an intermediate rail at a height such that a standard 120cm pallet plank would be about half way up the width of the middle plank when it (the 120cm plank) was standing on the edge of the 'hen/pigeon preventer' plank. The next three retaining rails were screwed to the inner faces of the corner posts at the same vertical heights.

In addition, diagonal braces were screwed to the inside of the corner posts to stiffen the structure further. A horizontal brace in the form of an 'X' was screwed to the top of the corner posts. This skeleton structure became very rigid with the addition of the 'X' brace.

For the front elevation I made a narrow panel the full height of the cabin from three 190cm long pallet planks. The door was made to fit the space left between this panel and the corner post.

The roof on the first design of cabin was a simple rectangular frame, larger than the footprint of the cabin, to which were nailed broad laths. A heavy-duty tarpaulin was secured to the outside of the frame.

The corner posts on one side elevation were reduced in height by about 25mm so that the roof had a pitch when it was put into place,

Subsequent cabins have had a double-pitched roof requiring the construction of two triangular panels which fit onto the top of the front and rear elevation. Two rectangular panels again with laths nailed to them are attached to the sloping faces and again a heavy duty tarpaulin fitted.

Assembly of the cabin.

Once erected in the workshop and everything checked for squareness the cabin was dismantled for moving into the garden. The frames for the sidewalls were left attached to the corner posts, the position of each plank for the rear wall frame was marked with its' location prior to unscrewing from the corner posts. Hence, there were two frames for the side walls each frame had two corner posts.

The whole cabin could then be moved outside to the prepared foundation of small stone chippings tamped down so as to feel firm underfoot. Obviously, I checked this to be not only flat but also level. 

Portable toilet anyone? Loading up at a Garden Open Day in Normandie

As long as the position for each component is clearly marked, assembly is a breeze, I know this as we have shown this homemade system at several exhibitions in the Region. On one memorable occasion, we displayed the whole system at two exhibitions in two towns in two days!

So now, if you'd like to, sit back and watch the film.

Thanks for dropping by and please feel free to share this article, comment, ask questions and if you'd like to be assured of getting the next post, then sign up to follow this blog.

All the best, Andy

© Andy Colley 2014



  1. Hi,
    The separate at the source concept is interesting. However, don't most folks going #2 also go #1 at the same time? How would that affect the system?

    1. Yes you're right there will always be some liquid in the solids side but this is absorbed by the sawdust sprinkled on after use. This also provides essential carbon to the medium and gives a greater surface area for the bacteria. If on the other hand a #2 found its way into the bucket of #1 then the aerobic bacteria wouldn't stand a chance.
      I know several people who have a single bucket system in their houses but because the bucket is emptied more frequently into the compost bin, there is insufficient time for anaerobic bacteria to build up.
      We decided on the two bucket system because we could put the collected urine to good use immediately in the garden and now we compost it in a separate bin, see: for my post on this. We will be able to use the compost from this anywhere in the garden (including the vegetable plots).
      Thanks for your question and for visiting my blog.
      Best Wishes, Andy.

  2. Hi,

    thank you for sharing your invaluable knowledge and experiences. I'm also building a compost toilet quite similar to yours. I see you use a tarpaulin layer for the roof but I don't know whether it is appropriate for my spaniard climate (very hot summers). Do you know another ecological alternative material instead of tarpaulin with better isolation properties? I pretend no to use tiles in order to not complicate the construction and to lower down the cost.

    Thanks in advance.

    Best regards,

    1. Hi Israel,
      Good question!
      I can think of a couple of alternatives that would work.

      Have you thought of using a metal roof? Galvanised sheets can be found for recuperation in most areas and although not exactly ecological, you would be using a recuperated material. It would be simpler to put such a sheet on a single-pitched roof.

      The other idea that we used on a hen house is to cover the tarpaulin with split bamboo (or whole bamboo canes if you can find enough). In between the canes we planted sedums where possible. The canes were held in place by a wire which was twisted around each cane at the top and bottom of the roof. The canes would resist the summer sun whilst the tarpaulin would still be able to provide the waterproofing. This roof lasted 10 years before the bamboo started to break down (due to the effects of rain and snow) but it still looked attractive even then. This link will take you to a close-up image of the roof:

      Hope these ideas are helpful and if you have any other questions please drop me a line.
      Good luck with your toilet and thanks for visiting the Green Lever.

      Best Wishes, Andy,

    2. Hi Andy,

      perhaps the option of using a metal roof is the most convenience solution. In fact I have some pieces that I can recuperate.

      Have you used EPDM material?

      This URL links to a photo with the ongoing construction. Inside the concrete foundation I plan to put a container to store the poduced waste. Once the container is completely full I will put the waste to the compost bin.

      Regarding the bamboo canes, they aren't in my zone, but there are other sort of canes that could be used, will less durability. Or perhaps palm leaves...

      On the ohter hand, your chickens look quite pretty...


    3. Hi Israel,
      I've had a look at your construction and the sloped roof is ideal for the metal sheets. I like the design, the removable container idea is really neat. We use our dry toilet all the time and it takes about 5 to 6 days to fill the 10 litre bucket. What capacity will your container be?
      I have used EPDM as a pond liner in the garden but some friends of ours who are ecologically renovating an old house have rebuilt an outbuilding and used EPDM as the waterproof base on the buildings' green roof.
      The birds in the photo are our fantail pigeons, if you would like to see the rest of the flock that we have, including old breed chickens and quail, then take a look at Sue's Youtube site -
      Will your toilet be a squat type or will you be installing a seat? I realise I haven't written the post for how I made ours although I posted the film 2 years ago.
      Keep us posted on your progress.
      Cheers, Andy.

  3. Hi Andy,

    my idea is to build a container (wood or metal) with the dimensions of the concrete base. By now, as a temporal solution, I will cut (along its length) a recuperated water container or even I could take an old bathub and put it inside. That will give me about 50 litre capacity. The important thing is to get a container that ease the process of taking it out and empty it into the compost bin. Another solution could be to have 2 containers available to exchange them in a faster way.

    I will build one seat similar to yours.

    Regarding the roof construction, and to compesate the lack of isolation properties of the metal sheets, I will use cork. I have some cork sheets available after having finished my mini-home recently.

    I've seen that Leroy Merlin in France has EPDM sheets but there aren't available here in Spain. I will search for another provider.

    Your pigeons are very lucky to receive such wonderful treatment from your side...


    1. Israel,
      It is a good idea to have a reasonable size of container, just beware of the weight of it when full - will you have to lift the container to empty it into the compost bin?

      Is the EPDM sheet to be for a water tank liner or pond liner? If it is, we bought ours from a big garden centre in the UK and I am sure there would be similar enterprises near to you.

      As a start, try these guys: Acuarios y Estanques Acuatica


  4. Thanks Andy for the link! I didn't find this provider. The m2 price is not expensive.

    Good point regarding the container size. Currently, the compost bin is at the surface level so it's not needed to lift it up.
    I also have to build a little pond to recycle the greywater coming from the house and I will use the EPDM sheet to do it.
    However, a friend of mine uses EPDM for building roofs and apparently it works perfectly, so maybe in a near future I could used it to make small constructions (i.e. to cover firewood).


  5. Hey Andy,
    We are in the middle of building our toilet shed and i was wondering if you had the plans/ pictures of how you made your loo box, i am quite interested in your two bucket system. Also wanted to ask about the compost system that you use.
    thanks Nicole

  6. Hi Nocole,
    Yep, the post on the seat is here:

    The one thing I should point out is that the seat is obviously quite wide so unless you have accounted for this in your shed design/ construction, the double seater may not be able to be put into place - that is one reason I designed the shed to have loose plank walls.

    For composting the solid waste, the post is here:

    As I explain in the first part of the post for the seat, the urine can be diluted and used directly in the garden, or even used as a 'starter' for a sluggish kitchen/garden waste compost heap, but I have made a urine composter and posted it here:

    Needless to say each of these stages has a linked film.

    We've been using the compsted waste in the flower beds and it really is the most wonderful medium. Some time ago I did a post and film where I show the end result:

    Hope this helps. If you need any more information please get in touch. Good luck with your project, I know that for us the flushing toilet is very much a thing of the past. Happy composting and thanks for visiting 'The Green Lever'.

    Cheers, Andy.

  7. thanks so much Andy for the links, all your info has been great. no worries on the size of our toilet shed it is probably 3 times as wide as yours. at present we have been digging a hole for the loo waste so we will be getting right onto the compost box as soon as we can.

    1. I'm so pleased you've found the information useful. Sounds like you've got yourselves the 'wide-screen' model of shed. You won't be dissapointed with the results from the compost bin, either.
      Many thanks for getting back to me.
      Best Wishes for the New Year, Andy.