My Composting Toilet




About: I really just needed a place to pimp some of my projects. The only problem is I never seem to get enough pics of what I'm doing while I'm doing it!

My tiny bathroom has less than 16 sq ft of room! Originally, my plan was to buy a commercial toilet. But as we saw how small the room was going to be we started looking at other options. Commercial composting toilets are pretty large to say the least! They usually sit higher and you almost need a stool to step up on whilst "doing the doo"! In fact I have seen a few tiny houses that did just that. Another thing we didnt like was the look of the crappers! They barely look like a toilet in a house and more like something from a space shuttle! The cost of them can be shocking also. I think the unit we were considering was around $900! On top of that you have to eat the shipping charges.

After weighing the pros and cons we decided to just build one (like everything else)! The idea was that if we built our own and it didn't turn out right then we didn't loose much. Plus, building one meant that it would match the rest of the bathroom.

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Step 1: Tools and Materials

As with all builds these tools are just what I used. I'm sure some of the power tools could be substituted for a star-drive, swamp-swival, power shark, or simply a multi-tool! But, thats up to you.
- Table saw = for cutting wood on a table!
- Miter gauge
- Router or Dremel tool = for dremel-ling
- Drill = for drilling
- KregJig = for ........jigging!
- Pipe clamps = for clamping pipes! ( not really)
-Various hand tools

2- Edge glued panels 3/4"x16"x6' (I could have made the panels myself but didn't want to take the time)
1- 1/4" dowel rod
1- toilet seat kit (I probably could have built this but my sanding skills would have left splinters in my butt!)
2- 2" hinges
4- rubber feet (of some kind or another)
1- 5 gallon bucket
2 - little brass catches

Step 2: Cutting the Panels Down

To cut all the panel material to length I first had to finger out the most efficient way to get the pieces out of the panels. Drawing stuff usually empties all the crap out of my head so, I took some time to diagram the panel layout! I cut two 19" pieces, and four 16" pieces. To do this I used the table saw and cut the pieces against the rip fence.

Once all the lengths were cut I had to rip the pieces on 22.5 degree angles. I set the blade angle to 22.5 then set the rip fence to trim the first angle. For these angles its hard to measure against the blade because, my saw's built-in ruler isn't very accurate. So, I move the blade tooth to the table and measure from the fence to the inner cutting tooth. The first cut is 15 3/8". I ran all the pieces through this cut to get the first angle on one side.

Next, I set the fence from 9 3/4" to the inside of the blade. I ran 2 of the 16" panels through this cut then reset the fence to 5 3/8". I cut the 2 leftovers and then ran the other 2 panels through this setup. That only left two more pieces so, I set the fence to the last cut which was 7 3/4". I finished the last pieces and moved on.

Step 3: Fitting Panels for the Toilet Base

After all the cutting, I figured out which sides would be the bottom on the panels and marked them. Then, marked a line on the inside-bottom about 2" from the sides of all panels. This is for drilling a pocket hole so the base can be fastened to the bottom panel of the toilet. We will also use the pockets to dry fit the base to a scrap piece of plywood later. Anywho, I used a square to mark a straight line on all the marks ( for the KegJig).

Usually I test the KegJig after setting up for new material. So, I set up 3/4" on the jig and the drill bit and ran a test an some table scraps! I then ran some screws into the test piece and made sure they didn't come through the bottom.

Next, I drilled all the pocket holes on the marks making sure that they were being cut on the inside only. Then, lightly sanded around the pockets ( to get the wood fuzz from around the holes) [sounds slightly erotic] ( woodchuck porn)!!

After breaking in the drill I screwed the panels down to a scrap piece of plywood. And, using a framing square I made sure that the panels were going down true. Once the base was in place I could see where the bucket should sit and the toilet seat. At this point I knew that the base was a little to wide to fit the 16" top and bottom panels. I decided to cut 1/8" off of the 4 shortest pieces of the base to make it a bit smaller. Then, reassembled the base on the plywood again and checked all the measurments.

Step 4: Gluing and Pegging the Base Together

First, I decided to cut an alignment guide out of a piece of scrap. This was just so I could hold the panels together at the tops while drilling the pegs. I even drilled pocket holes in it to fasten it to the base. Once I had 2 panels together I drilled a 1/4" hole just on the edge in 2 places. This put the hole through one panel and into the adjoining panel about an inch deep.

After that I took the alignment jig off andI ran masking tape on both sides of the glue joint to keep the wood clean. To apply the glue I took one of the panels off the plywood base. After applying the glue I replaced the panel and filled the holes with 1/4" dowels. When the joint was held firmly together I wiped the glue off, cut the dowels off, removed the tape, put the screws back in, and moved onto the next glue joint. I moved around the base and did one joint at a time being careful not to screw up the dowelling direction!

Once all the joints were done I let the base dry for a while.

Step 5: Building the Bottom and Fitting It

Once the glue was dry I removed the screws and pulled the plywood away from the base. I took one of the 19" panels that was cut in step 1 and laid the base onto it. At this point I was happy I recut the 4 short panels because it fit perfectly! I then situated the 5 gallon bucket to see how it was gonna fit with the toilet seat on top. I wanted to make sure there would be enough room for the seat hinges.

Once the bucket was where it needed to be I marked around the bucket and marked the little center circle. With a Dremel tool and a 1/4" mill bit I cut the circles about 1/8" deep. This was to keep the bucket from moving and so it could be positioned easier. After that I checked everything and also marked the excess on the bottom panel that needed to be cut.

For this cut I removed the rip fence on the table saw. All of the cuts on the bottom panel were cut free-hand because the angles were kinda funky! There was no good way to jig the cuts!

Next, I checked the bottom fit to the base and placed the bucket inside. I originally cut all the base panels 16" but, the bucket is only 14.5". To fit this properly the base had to be cut true all the way around, so I used a 16" ruler to set across the top and mark inside the base where to cut.

To cut the base I set the rip fence and set the base on the table. I cut the base one panel at a time, turning it after each cut until the top band of the base fell away!

Step 6: Building and Fitting the Top Panel

To build the top panel I needed access to the inside so I left the bottom off temporarily. I laid the the other 19" panel on the base and marked around it to cut the excess. In the same way as the bottom, I free-hand cut the top on the table saw.

Next, I flipped the base upside down with the top on and marked the inside around the base. This was done so the top could be notched around the edge and push down on the bucket. This keeps the bucket from sliding and keeps the top more supported in the center when I sit on it ( great visual huh!).

The notch is cut by setting the fence from 3/4" to the outside of the blade and the cut heighth to 1/8". I ran all 8 edges through the saw. Then, I subtracted 1/8" from the fence and cut the 8 edges again. I think this was done like 5 times before finishing! I used a chisel to cut all the leftover wood out of the edges and finished it with a file.

I tested the fit to the base and also marked the holes for the toilet seat. I drilled the holes and mounted the seat to the top panel. All that was left was to mark the hole for the pooper and cut it out! For this I drilled a starter hole and cut it with a jigsaw.

Step 7: Assembling the Toilet Base and Testing?

To connect the bottom to the base I used glue and screws so before hand I taped the glue joint to keep the wood clean. Then, I applied the glue and laid the base down and clamped it with pipe clamps. Next, I screwed the base down at the pocket holes to pull it in evenly. This had to dry all night.

The next day I removed the clamps and replaced the bucket to reference where to mount 4 padded feet. These are round feet with a 5/16" threaded stud and plugs that are pressed into place. I drilled the holes, inserted the plugs, and screwed the feet in.

Hell!!! I even had time to take a few glamour shots in the bathroom! You know, show the little guy his new home! Make sure its comfortable and enough room to read!!

Step 8: Finishing Touches Before Stain and Varnish

To make it easier to get the bucket out I installed hinges for the top panel. The hinges used were flushed so I only had to recess the base. I used a file to cut the recesses because end get grain is tough to cut with a chisel. Then, using a pilot bit, I drilled and screwed the hinges down. Attaching the hinges to the top was a little tricky. I marked a tiny little drillbit with tape so I knew where to stop then, used 1/2" screws to fasten it ( this time I didn't get pissed and cut longer screws off with the dremel tool!).

After a bit of thinking, I decided that the top looked kinda plain so I cut a 25 degee angle around the edge just for decoration. Later I realized that the rounded edges felt better on bare skin too! I also, didn't like the seat lid not having something to lean against when open.

To fix this I found some 1"x1/8" pieces of steel about 4.5" long. I marked them high enough to catch the lid and bent them in a vise to about a 75 or 80 degrees. Next, I drilled 3 holes in them and screwed them down to the base. This caught the lid from falling against the wall.

Lastly, I removed all the hardware and filed and sanded everything and rounded over all the sharp edges.

Step 9: Staining and Varnishing the Toilet, and the Finished Product!

Once the toilet was sanded and clean I used some leftover stain from a cabinet that was built way earlier. I just applied it, wiped off the excess, and let it dry.

The next day I woke up to 35 degree windy weather! I knew the temperature was too low for the varnish so I had to wait for the sun to come out and find a sunny spot away from the wind. It took all day to apply the varnish ( just 2 coats)!

After the varnish was completely dry I reassembled the toilet and attached the little brass catches for the top. Then I took a few more glamour shots!

Just in case you didn't know, the idea behind these toilets is pretty simple. You just lay a bed of shavings down in the bottom of the bucket and do your business! When you are done you cover it with more shavings or wood ash or even sand! Lucky for me we have been saving the shavings from our planer for this occasion!

Check out the rest of our tiny house build at Enjoy!



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    17 Discussions


    3 years ago on Introduction

    Pardon an urban-dweller's ignorance, but I have a few questions:

    1) How often do you empty your bucket, i.e., do you wait until it is completely full, or 3/4 or....?

    2) What do you do with the "compost"? Does it go into your garden/land, etc? Does it eventually become fertilizer for plants/garden?

    3) I assume you must also use TP that is biodegradable, yes?

    4) Can you urinate into the bucket as well as poop?

    5) What is the possibility of the plastic bucket degrading?

    Thanks for this, very informative. Thinking about this for our 1-bathroom house, maybe in the back garage/office. If we're buying the kitty litter/peat moss, etc., I wonder if we will save much in regard to water? Also, we have a very small back yard, I suppose we could dig in the compost....

    Thanks in advance for replies to queries.

    Michael C

    4 years ago on Introduction

    you could always use enviromentally safe kitty litter. It has saw dust, and corn husk and other organics that help control odor, and it is still safe for the garden.

    1 reply
    gunguruMichael C

    Reply 4 years ago

    Good idea. I think that is the the same stuff they sell for dry toilets. Right now we are sticking with shavings because they are free!


    Reply 4 years ago

    I thought about adding a fan. But, figured I would try it as it is to see if anything else is needed. So far its not bad but, we may have to use peatmoss in the media to obsorb odors.


    4 years ago on Introduction

    I can just hear it now --- "It's your turn to empty the bucket, I did it the last time!".

    "You filled it, you empty it!"

    "Maybe if you didn't pig out at dinner there wouldn't be a problem"

    "you left the seat up again!"

    "I told you to go easy on the beans, now look what you did, who do you think is going to take care of that?"

    "Your gonna need a bigger shovel"

    "Oh man, even the cat wants out!"

    5 replies

    Reply 4 years ago

    Wow........I never thought about that.


    Reply 4 years ago on Introduction

    Just a little potty humor, I raised 3 kids, I have heard some of those.


    Reply 4 years ago on Introduction

    Actually the biggest problem with it where I live is everything would be frozen solid for six months of the year. You would need a really big bucket.


    Reply 4 years ago

    Actually this is going to be our regular toilet! It stays indoors.


    Reply 4 years ago

    I think thats called "Permapoo"!!


    4 years ago

    I like it, though I think I will use peat moss instead of sawdust or sand after each use of the toilet. It's supposed to trap odor better.

    1 reply

    4 years ago

    You should add this to the apocalypse contest.

    1 reply