8×20 Solar Tiny House Plans – Version 1.0

8x20 free house plans

I just put the finishing touches on the 8×20 solar house and uploaded the plans. I can see how SketchUp Pro with the bundled presentation building software, Google Layout, would be a real time saver and would really improve the final output. But I’m still amazed at the high quality 2D and 3D renderings that are possible with the free version of SketchUp. I’ve posted the first version of the plans for the 8×20 online for your review. I’ll take the feedback posted in the comments and try to do a quick revision.

I know I’ve missed some important things like specifications for hardware and lumber in the plans. I’ve been thinking that 2×4 framing, 24″ O.C. and 1/2″ plywood or OSB for the sheathing. Anyway take a look at the plans SketchUp file and let me know what you think.

8x20 tiny solar house view from above





33 thoughts on “8×20 Solar Tiny House Plans – Version 1.0

  1. James says:

    Hi Michael-

    Thanks for this finalized version of the plan. I have sent it along to my uncle for review.

    Regarding the bed… have you planned some kind of flip-down wall-storage or something? I'm not sure I fully understand from the drawing.

    I was thinking a good alternative to a loft in this design might be a floating “bunk bed” with desk space underneath… πŸ™‚

  2. malconium says:

    Hi Michael,

    I like the overall design too. I think you may be over designing your frame in a couple of places though. That of course is not necessarily a bad thing. The one place that jumps out in my thinking is the use of the diagonal braces. I think if you are using 1/2″ plywood or OSB and especially if you glue and nail it to the framing that you will find that the diagonal bracing is not needed. I know you said that you left hardware information out of your design so far but one thing that you might want to add that can be wood is some plywood gussets at the peak of your roof rafters. I would suggest 1/2″ plywood (scraps from your sheathing) nailed (or screws) and glued at that intersection.

    Keep up the good work…


  3. James says:

    Man, that would be sweet! I am still lost on how we are going to implement a grey water holding tank near the drain (so we can use it at RV parks and stuff) and also how to implement the electrical system properly so that it can be hooked up easily to a simple extension cord… wouldn't mind also being able to hook it up at an RV park, but I don't know what the standard is there either.

    Michael, I was inspired by another version you posted a picture of at one point, the 8×20 with dormers. We are most likely going to go with a modified sonoma shanty design that adds dormer windows for loft head room and lighting.

    While we do love your 8×20 solar house, we really want to implement a loft for the extra floor space. And it seems easier to add dormers to the Sonoma Shanty than it would be to add a loft to the solar house, so we're leaning that way at this point.

  4. craigmoorhouse says:

    I think this is a brilliant design. The best way to utilize solar energy is with passive solar storage – the – sun shining on a surface and heating it up. In the summer – turn the mobile home so it faces north to keep things cool or build louvered shade surfaces out of corrugated steel to reflect direct sunlight away from the interior of the house. You have 4 excellent surfaces for your solar electric panels – if you have two panels – put then on the south facing side in the winter – move them to the north side in the summer and turn the house so it is facing north ( and the solar electric panels will be facing south).
    If you finish this houses' interior walls with gypsum board it would make a great heat sink for winter and would help cool the house in summer.
    What the “green” housing movement needs is the architectural equivalent to the V.W. Bug – funky and affordable – if more people are living in designs like this the less resources will be thrown away in ill-designed McMansions.

  5. ej says:

    I would move the toilet to the other end for max distance to kitchen, put a small closet/cupboard at door for coats & cleaning supplies.

    Great visualization.

  6. michaeljanzen says:

    Very cool Mark… I didn't know this was happening. I have been busy the last few nights working on my Reburbia entry… but will definitely look into this Guggenheim competition too. Thanks!

  7. michaeljanzen says:

    Thanks Craig for point these details out. I wanted to elaborate on some of the details but the night I posted this I was beat and skipped writing it all up.

    You've read between the lines and have seen some of the method to the apparent madness of the solar house with gables. I do have a few details left that need fixing like louvers, eaves, or shutters, and as you pointed out… some kind of thermal mass.


  8. michaeljanzen says:

    Good thinking. Actually if the toilet were a composting toilet (no need for water) the shower would make sense closer to the sink anyway for simplified plumbing. Thanks EJ.

  9. Mike Kattelman says:


    I own an 8′ x 20′ shipping container cabin, which is complete on the inside, but which needs a roof. I was looking for a design that would shed snow and allow me to install solar and my water tank between the rafters. Your roofing design is what I have in mind. Great job!


  10. halmooney says:

    A question about portability. I really like your design, but I’m wondering, for people who are building somewhere other than where the house will end up, can a house this tall be transported?
    Here in Florida, the shed people have to keep their roofs heights low, because the law limits to overall transport height on the road.
    An interesting modification would be a collapsible peak, that could be folded for moving, and popped up on site. Thinking…thinking…

    • Michael Janzen says:

      In many US States 13.5′ is the limit for transporting a trailer/vehicle without a permit. This design is lower than 13.5 feet.

      I think a flexible/transformable roof is a great idea but I would personally avoid it due to the complex engineering needed… especially for a roof. But I can see that with some effort and hydraulics it could be done.

  11. markfallin says:

    very sweet work. i have a little solar experience. would love to see where you’ve evolved this design. is there a version 2 yet? may be able to offer some assistance.

  12. JT says:

    Much of this looks very good. A question: Have you allowed space for some sort of water heater, propane storage, etc., or were you planning on using an on-demand system?

    Malama pono,


    • Michael Janzen says:

      Hi JT,

      I left that out, but I think a utility closet accessible from the outside could be placed behind the toilet or shower.


  13. Jerald says:

    Question: I’m looking at building a tiny house on a PJTrailer frame that has 3″ channel crossmembers 24″ OC under the 2″ pine decking. Is it structurally necessary to add 2×6 floor joists on top of this? Or is it OK to simply build on the existing frame and decking and simply add subfloor sheeting directly on to the decking?

    • Michael Janzen says:

      That is not an approach I’ve seen done, but have heard several people as the same question. I’m not an engineer but I suspect the steel frame of the trailer would be sufficient as a floor since they are usually strong enough for the whole house. The disadvantages that spring to mind are:

      1. Fewer options for securing the walls to the floor since the foundation is steel. Although it would really depend on the trailer’s construction.
      2. Less space for plumbing/drainage.
      3. Less space for insulation.

      I don’t think I would try it myself without carefully considering the specific trailer and how safe it was to skip the wood floor.

  14. Curt Box says:

    Like your design. Your drop down Murphy bed could serve double duty if you included some built-ins in its face. IE: on the kitchen end you could have a drop down butcher-block work surface and on the opposite end a drop down dining table. And since the Shakers hung their chairs on the wall, maybe a couple of wooden folding chairs could be stored flat between the two drop down tables….

  15. jpatti says:

    I want to do something similar, but with the entire length of the roof as a shed roof. That way, the upper windows can be along the entire wall.

    I doubt there will really be much solar benefit to this as my house won’t have much thermal mass. But it seems to me that a wall of windows will open the space up and make it feel so much less crowded.

  16. joni says:

    i will be building an 18 by 20. do you think this would be enough space for 2 bedrooms and if so what would be the best way to accomplish it? it will be for me and my 1 year old daughter. any suggestions would be appreciated. thanks!

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