ICS SIPs Trösta Outhouse

Luke Danielson sent me this interesting concept for an outhouse that I thought would work for someone with a tiny house. Here is what Daniel has to say about his design:

I was skeptical at first but after reading Humanure (everyone should read this book!) I was inspired to design an outhouse that incorporates a composting toilet. I know there are many out there that have been doing this exact thing for years, but I’d like to think that with the use of SIPs, the Trösta (“comfort” in Swedish) could be one of the most efficient.

With R-28 closed-cell SIP walls, roof, and floor, the unit would require very little input to heat or cool. Plus, with temperature being crucial to the composting process, it just makes sense to have a highly insulated outhouse. I designed it with the use of 4×8, 4×9, and 4×10 sheets of OSB to keep scrap and price to a minimum. With is being a bit larger than typical outhouses, you could use that extra space as a storage shed, or even split it with a divider wall for two toilets for a Men’s and Women’s unit.

With the use of the ICS’ camlock system and one-piece corners, the unit could be closed-in in just a few hours.

Luke Danielson
Takeoffs/Panel Design
Insulated Component Structures – Rocky Mountain, Inc.(ICS-RM)
Manufacturer of Structural Insulated Panels (SIPs)

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Jesse S - February 14, 2010 Reply

Luke, what is the cost of the ICS components in this design? (wall panels, roof panels, floor panel)?

    Luke - February 15, 2010 Reply

    This unit should come out around $2000, depending on the amount of window/door openings, embedded electrical boxes/conduit, etc.

Daniel Westman - February 14, 2010 Reply

I like the name, sounds like something you could buy at IKEA! I agree with having a highly insulated outhouse. If you can get your hands on a cheap solar panel you could even incorporate floor heating!

    Chelsey - February 14, 2010 Reply

    Or maybe seat heating, for my neck of the woods.

alice - February 14, 2010 Reply

If you don’t have a heated outhouse you definitely need a styrofoam seat. Instantly warm when you sit on it. All the best outhouses in the Yukon have them, though they do get a bit grungy after a while. Some people like to keep the toilet seat in a warm spot and take it out with them every time. A friend of mine had electricity at his place so he rigged up a car heater in the outhouse plugged into a porch light. He’d hit the switch and by the time he got his boots and coat and whatnot on the outhouse was almost warm.

Jesse S - February 16, 2010 Reply

OK, nice concept, but $2000 for a 4×8 outhouse? That’s almost $70 per square foot. For that price, I want to be able to live in it! A stick-built unit with insulation should cost about half that, or less, in materials.

    Luke - February 16, 2010 Reply

    True, it is just a concept, and not for everyone.
    You could always do a stick built structure for cheaper, but even if you spray-foamed the walls, roof and floor (which is actually MORE expensive than SIPs after material and labor costs are factored in) and with each stud acting as a thermal bridge, it would be hard to achieve R-28 in a 2×4 space.

      JD - February 17, 2010 Reply

      I think the point is that heat must be maintained to compost. If not composting, then go ahead and save on insulating. I used an outhouse for years in NW Alaska without heat (thanks to Styrofoam seat as suggested above).

      I’m interested in this – thanks for sharing. I have a shop and am interested in using composting as in Humanure. Living way up north, this article seems to suggest it is possible – probably still need solar collectors (some kind of heat source) to maintain compost temps. $2-3k would definitely be cheaper than the $15K+ to run sewer lines or septic system.

brad - February 18, 2010 Reply


I think it is great, on one side could be garden storage, and the other could be Trostahaus. I will use it in my backyard, so when I am playing polish frisbee, grilling, or anything outside I can do my business in peace without going inside. I think I will even build a small fridge in the wall, so as I break the seal, I can grab a fresh cold one too!


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