Another Northern California tiny house on a trailer build

Hey everyone,

I am building a tiny house on an 18 foot long 8 foot wide 10k double axle trailer. It's my first building project and I have a deadline of August 24th when our lease is up. I'm using locally sourced and milled lumber and sheep's wool from Oregon Shepherd for insulation. The roof is a Corten corrugated steel roof. I'm going with no plywood, no vapor barriers (except tarpaper against metal surfaces) and air gaps between my insulation and my siding to try and build a breathable wall system. No bathroom, we are happy to poop in the woods. The shower will be a showerhead coming out the exterior and we will build a little outdoor screen wherever we land. The sink will also have mirrored plumbling to the outside allowing an exterior sink to be attached as well. I hope to hear your advice and experiences as my build progresses and learn from you all.

Started in May, which is subfloor/floor month. June will be framing/roof/exterior siding, and July and August will be everything else.

Here are my plans to begin with:

The fridge will be propane... same with the stove and the on demand hot water heater.

Trailer with aluminum flashing and tarpaper attached

Attaching 2x4s with self-tapping trailer deck screws. 2x8 joists will be nailed into these. Most of my lumber is spruce- light and strong

Screwing and nailing in the joists (went with both)

Subfloor and sill plate finished. 2x4 furring strips bolted and screwed in. The floor will be 2x6 shiplapped fir that will run horizontally, nailing into the furring strips and the joists. The sill plate pictured is some reclaimed old growth redwood, which is also bolted and screwed in. Finally, there's 1x wooden spacers attached across the bottom. I stapled plastic nursery netting to this, and it will provide my air gap for my wool insulation. Theres my newborn baby too
I welcome all comments and will update soon! Thanks!

Floor put in 7/7

Put in 80 pounds of sheep's wool (about half a pound per square foot by 6 inch cavity) and attached tongue in groove 2x6 douglas fir flooring directly to the joists and furring strips. I used a nailer to put 2 inch staples into the grooves. Was worried about moisture getting into the wool at night so hustled it out in 1 day with the welcome help of my housemate.

Next will be the framing!

Also ordered a Hobbit cast-iron woodstove http://www.hobbitnorthamerica.com/ and an on-demand propane water heater, the Atwood OD-50. And ordered my Corten corrugated steel roofing http://www.cortenroofing.com/ which should come end of June.

Looks like a great project! I think as you use it you'll come to see how you need it to be, so be prepared for future adjustments to the layout. leave yourself options to change the configuration, because while Living In The Rough might seem exciting at first, it can get old pretty fast.

About the no bathroom, how about a small closet for a shower and a 5 gallon bucket compost toilet? Because the woods are full of poison oak and mud, ticks, bees and hornets, and it's a lousy trip out in a storm. If you ever get a permanent place to park it you won't want to fill up the land around it with raw sewage and paper. Trying to keep the interior clean while tracking in mud and leaves is a real struggle, so the fewer trips in and out, the better.

Showering inside when it's cold is not really fun, but showering outside with a curtain at the side of the road when it's freezing is really not fun. A small closet could hold a showerhead with the movable bucket in the shower. Draining off your gray water into a discrete bucket to be carried away is a lot less invasive than splashing it all over wherever you are.

Make sure that everything is packed solidly into place while driving. No loose things. Make sure cupboards shut really tight with solid fasteners.

If you plan on using propane, there are laws about driving along with propane tanks, and you should never be inside with one while using it. Heaters and water heaters that use propane need vents to the outside because of the odorless carbon monoxide. It would be a good idea to get a carbon monoxide alarm that runs on batteries.

There aren't many places to park these vehicles without big expense, so wherever you end up you will be dealing with the permission of people who have the land, and you'll want to look clean, decent, details-under-control types, and not scary homeless folks. There are a lot of people trying to live out on the side of the road these days, and the police are having to deal with a lot of it, so they will keep track of you more than you might think.

also, a small closet shower also gives you a place to put muddy, wet shoes, wet rain coats, wet rags and towels, anything that is dirty or needs to dry off that can't be outside. It lets you hang up a broom and a dustpan, and you can even set a small tool box on the floor out of the way.

Looks like the start of a cool little house! If you are plumbing water to the exterior then I think it would be wise to recess the fittings and add insulated covers to avoid problems in the event of a hard freeze. Or perhaps you could add an interior shut off valve that is higher than the exterior outlets and let them drain out to avoid having issues with pipes freezing.

Another thing to keep in mind is weight. Just because a trailer is capable of handling X number of pounds doesn't mean it is always wise to push it to that limit. A heavier trailer will consume more fuel to move as well as increase the braking distance for the towing vehicle. If the trailer is driven off pavement then it will be significantly move difficult to move around and should it get stuck then it will be REALLY stuck. I doubt it would be any fun having your home stuck in a less than ideal location. If it won't be leaving the pavement then this is less of an issue.

There are a number of methods you can look into which can yield a strong frame without using as much wood as the conventional North American platform framing method. This Blog On Swedish Platform Framing shows a few methods to save wood, weight, and increase area for insulation. I personally wouldn't use full size studs 16" on center. Double-wide trailers tend to use 2"x3" framing members which is a substantially larger structure than a tiny house. While having only ~2 1/2" for insulation could be problematic, the point I am trying to illustrate is that it doesn't take huge amounts of wood to make a very sturdy tiny house. If you are using 2x4 or 2x6 studs then you could drill a bunch of holes up to 1/3 of the width of the board without sacrificing structural integrity.

You can also use much thinner wood for the interior and exterior and add metal brackets to the corners to increase rigidity. It really doesn't take all that much material to make a very sturdy structure when the dimensions are of a tiny house scale.

Your plan to avoid a vapor barrier is a good one! I have fixed numerous houses that were ~2 years old that had paint and vapor barriers trap moisture inside walls. By the time the leak was detected it was far too late and cost thousands to repair. Having breathable materials will help avoid mold problems and make leak detection easier and far less costly to fix. Using thinner wall sheathing can help it breathe a little better without greatly affecting insulation.

I have never build a trailer home, so my comments are not proven.

- I would be careful with nails. You will get vibrations when driving on most surfaces and a disintegrating house might be not ideal. There are wood screws that are designed to prevent loosening.
Using dowels in combination with a good glue might work too.
- The weight: The weight of most parts can be reduced at the cost of more labor, by laminating / gluing light wood between strong wood.
(The Gougeon Book on Boat Construction is a great reference for lightweight wood constructions)

There's a baby involved here? So....a bathroom isn't an optional thing, it's crucial. Between the poop and the spitup, you're all going to need warm, safe showers!!

You did notice on the stove that it needs to be installed away from the wall? How far do combustible materials need to be away from the wood burning stove?

400mm/16” sides, 450mm/18” rear. Clearances can be reduced by half with a non-combustible heat shield. And the hearth needs to extend an extra 12" of noncombustable material in front and 6" on either side. I would recommend a 2" rim around the hearth because little pieces will roll out of the stove and onto the hearth, and if they keep rolling, and they are red hot (and they will be) they will be) they can end up on the floor or a rug (which not a good idea in front of a stove)

So you've got to have 3 feet from the wall front to back and almost three feet side to side. It won't be tucked into the corner like your drawing.

And if there's a baby involved, there needs to be a very sturdy NON-METAL guard (that won't also get hot) around that hot stove to keep little hands and tumbling heads away from a 600+ F stove.

Be sure it's not too high off the ground, and that you don't plan to pack things on the roof. Yesterday I went under a train track on a road that had only a 12-foot clearance. A lot of freeway overpasses are 15 feet

Obviously I'm worried about you guys

I thought of a couple more things. I guess you realize that this thing needs license plates and tags, so it will have to pass a road-worthy inspection and be up to Code, whatever that may be, according to the DMV. One reason the Hippies in the 1960's used buses is because they already had license plates and tags and they could get away without inspections of camper-like interiors. And if it passes inspection it will be given a value, maybe several thousand dollars, and that is what the price of the tags are based on.

The other thing about your insulation, the sheep wool is flammable. It's really crucial, when putting a connection through the wall for a wood stove, that it be the piece that is specifically for going through a wall and 600 F temperatures. Wood is obviously flammable, but you'll want to know the temperature at which sheep wool bursts into flame, because the special piece that goes through the wall will be hot, but it's built to not set wood on fire, not other things.

So before you drop all your hard-earned money into it, be sure you can actually take it down the road.

Thanks for the comments!

July has seen a whirlwind of framing.  Two experienced builder friends of mine came through and helped me out for free, which has been amazing.  I'm so grateful to them.




Building all the walls on top of each other on the ground... a bit unusual


The wood is local spruce, strong and very very light.


All in 2 days... framing is the fun and easy part I'm told.

Now on to the blocking and roof trusses.


Blocking is a family affair...
The diagonal bracing will help with shear, which is an issue since I'm not using plywood sheathing.  Running my interior siding diagonally will also help a lot with that.


I love the trusses.  Simple, low-tech, and amazingly strong.  A plywood gusset sandwich is nailed and glued onto 2x4s.


Putting up the first of the 10 trusses.




Redwood fence boards (2nds that I picked up for a dollar a piece) as skip sheathing on the roof.  I don't want to use plywood because it would ruin the breathability of my walls.






I decided to add one 36 inch strip of tarpaper along the bottom of the framing to protect the studs from saturated exterior siding.  Our winters here are very wet.  It shouldn't inhibit the ability of the walls to breath since the wall cavities will allow airflow all the way up and down.


And there we are.  Ready for the roof and exterior siding (which will be 1x6 tongue and groove cedar).  Only step left before that is tarpaper on the roof.


Thanks for reading!

Very nice build. May I ask what your cost is to this point?

Im guessing around 8 or 9 grand at this point.  (That does include some tools Ive been buying because I started with virtually no tools...)  I expect the total to come in between 12 and 15 grand.