Detailed Composting Toilet Build Instructions

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TRACE & CUT WOOD PIECES

Cut out top, bottom, and back blanks

  • Top dimensions L24” x W16”
  • Bottom dimensions L24” x W16”
  • Back dimensions 18” x 9”

Note: a 24” x 48” x ¾” sheet of plywood is all you’ll need.

Cut eleven 1” x 2” x 18” supports (Note: avoid dimensional 1x2’s. They measure 0.75” x 1.5”)

Cut out the tracing plans/template using scissors or an exacto knife.

Take your top blank and place the cutout template on top, marking a clear cutting line. Use a screw or other sharp point to mark each center screw hole location. These are marked with Xs. Using a jigsaw or bandsaw, cut out the outside profile shape for the top and bottom. Also cutout the inside opening on the top piece.

Drill holes on the points where the X was.

Countersink drilled holes.

Align the traced top blank with the bottom blank and secure with several 1.5” screws. You don’t need to screw every hole - just a few to hold the two pieces together while shaping.

Using a belt sander or heavy grit sanding block, shape the area you just cut so they match up nicely. (Sometimes the jigsaw blade can wander, so sanding ensures a consistent shape from the top to the bottom.)

Extend the top holes to the bottom. You’ll need to swap and remove the screws that are securing the top to the bottom and replace other holes with screws to secure.

Once all the holes are extended from the top to the bottom, place the tracing template back on the top and mark small tick-marks on the side of the top where the supports will go. Once this is marked on the top, use a speed square to extend this line to the base. This will make installing your supports much easier!

Remove the screws securing the top to the bottom. Using your jigsaw, cut the inside shape for the opening on the top. This cutout is only for the top.

 

ASSEMBLE WOOD BASE

Take your bottom cutout and add counter sink holes to your pilot holes, ensuring they are added on the bottom of the base.

Add the #9 x 2” screws to each hole on the top and bottom cutouts.

Assemble! Start with securing the top to the rear. Add one support at a time by lining up with the support marks you made on the side of the top, and secure each with a screw. You can optionally glue each support to the base and top, making the base more stable.

Flip over the partially assembled base and add the bottom by lining up the support marks and securing each support with a screw.

 

INSTALL METAL SHROUDING & TRIM

Rough cut metal pieces using a jigsaw with a metal blade.

  • Top Piece Dimensions: 15.5” x 22.5”
  • Shrouding Wrap Piece Dimensions: 19.5” x 54”
  • Metal Trim: ~54” Dead Soft Nose Trim

Wrap and attach the shrouding wrap piece. Secure at the bottom with 5-8 fasteners. The top will be held in place by the trim. For a temporary hold while working, use ratchet straps to hold the shroud wrap in place. This allows you to get everything lined up perfectly so you can use your hands to secure the fasteners.

Place the top metal piece on the toilet top and install trim over the top and front metal pieces starting from one of the back corners. Use fasteners provided with the trim. Firmly press trim down before securing so there are no gaps between wood, metal and trim. Continue securing until you reach the opposite corner. Remove excess trim with a hack saw or angle grinder.

 

INSTALL TOILET SEAT

Place the seat over the top opening allowing for consistent space around the seat. Mark your seat mounting point locations, drill holes, and add hardware.

Every toilet seat has different hardware. Most standard porcelain toilets have a very thick base and the hardware is made to accommodate this so you may need to modify/trim the seat hardware to fit your DIY toilet. I like to install T-Nuts on the underside of the top that matches the seat hardware. You don’t want to have the seat hardware sticking down inside your base as it will interfere with the bucket placement.

 

INSTALL VENTILATION SYSTEM

If you’re using our ventilation kit you can proceed with the following instructions. If you plan to vent your Throne via a different method you can proceed to the final step.

Rear & vent opening - cut out fan opening in rear. Add trim on the inside for a flat surface. Add rear flange. Add holes in the flange to secure the fan to the flange.

 

ADD RECEPTACLES & DIVERTER

Place the 6-gallon bucket inside the base and push all the way towards the back.

Add the 3-gallon liquids jug* in front of the bucket and make sure the jug is firmly against the front of the base.

Slide the bucket forward until it reaches the jug.

*Note: If you are using a different jug than the 3-Gallon water jug you may need to make some stops for the liquid jug so it will align with the diverter.

Install the diverter by simply dropping it into place. The liquids funel should seat into the top of the liquids jug and the solids opening should sit inside the bucket. The diverter is not attached to the toilet so it can be easily removed when emptying receptacles.

 

WELL DONE!

Now it’s time to take your inexpensive, attractive, and easy-to-clean composting toilet for a spin!

SHARE YOUR STORY

Help others in the off-grid and tiny-living communities to confidently build their own composting toilet.

  • Tag us if you’re posting on social media
  • Send us some photos so we can see your work
  • Write a review on our website

I appreciate any feedback you have and can’t wait to see your toilet!

- Nick Peterson

Throne Composting Toilet
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