The Timber Arc Composting Toilet is one of the most architecturally distinctive composting toilet buildings in the UK — a striking half-ellipse form originally commissioned by the Centre for Alternative Technology in Wales. At £13,300 it is our largest single-unit bespoke composting toilet, and it is built to the same exacting standard as every structure that leaves our Mid Wales workshop: handcrafted, sustainably sourced timber, designed to last a generation and to make a statement wherever it stands.
An Architectural Statement in Sustainable Sanitation
Most composting toilet buildings are functional boxes. The Timber Arc is something else — a considered piece of architecture that earns its place in a designed landscape, a heritage setting, or a high-profile public space. The curved profile draws the eye, the quality of the joinery is visible at a glance, and the natural timber finish weathers gracefully into any rural or semi-rural environment. If you need a toilet building that people will photograph rather than ignore, this is it.
Proven at the Centre for Alternative Technology
The original commission came from CAT — the internationally respected environmental education centre near Machynlleth in Mid Wales — and the design has been refined through real-world use in a high-footfall public setting. The wheelie-bin composting system it uses is the same reliable approach we use across our whole range: robust, low-maintenance, and genuinely odour-free when managed correctly.
Ideal for Public and High-Profile Sites
The Timber Arc suits visitor centres, nature reserves, country parks, festival sites, educational establishments, and any location where the toilet building is part of the experience rather than hidden away. Its robust construction handles frequent public use, and the waterless composting system means no connection to mains drainage — making it ideal for remote or protected sites where groundworks are restricted.
How the Composting System Works
Waste falls into a 240-litre wheelie bin beneath the unit. A urine separator diverts liquid away from the solids, which dramatically reduces odour and accelerates decomposition. Adding a carbon material such as sawdust or wood shavings after each use speeds the process further. A second bin rotates in while the first rests and matures — typically for 12 months — before the finished compost can be used on non-food growing areas. The system is self-contained, low-maintenance, and entirely chemical-free.
Bespoke and Made to Order
With over 25 years of experience building composting toilet structures in Wales, we can adapt this design to your specific requirements — size, internal layout, accessibility features, cladding finish, or integration into a wider building scheme. Every Timber Arc is made to order and delivered fully finished to sites with vehicle access.
What's Included
- Timber arc building — half-ellipse profile, handcrafted in Wales
- Urine-separating composting toilet seat
- 240L wheelie bin composting system (two bins for rotation)
- Internal ventilation system
- Fully finished interior and exterior
- Delivery to site (vehicle access required — no foundations needed)
Delivery
Due to its size, delivery of this building is not included in the product price. Delivery costs vary depending on your location and installation site — please get in touch for a quote.
In most cases we carry out the installation as well as the delivery, travelling to site to build and install the structure for you. If you have sufficient manpower within your own team to handle installation, that's also an option. Either way, we're happy to discuss what works best for your project — just drop us a message.
Specifications
- Framework — Douglas fir
- Base — pressure treated timber
- Cladding — cedar or larch
- Door — cedar
- Roof — corrugated steel and clear GRP plastic
- Urine separator — ABS plastic
- Toilet seat — varnished plywood
- Door hardware — galvanised steel
All timbers are oversized for additional strength and longevity.
Have questions?
Visit our Compost Toilet FAQs
