Tiny House

The design began with some sketches on paper and a listing out of the limitations that I had to deal with. These included the need for mobility which imposed size limits on how big a mobile vehicle could be. There was also the exploration on just how minimal I was willing to be with the design and how creatively the space could be used. I spent a great deal of time looking up space-saving designs and multi-purpose furniture that would give me the most use of a limited area.

This rendering shows what the interior will look like and how the storage is planned in such a way that the south face will be open to the sunshine while the north (cold) face will be used for storage so as to use clothes, towels, etc as extra insulation. Some other space-saving amenities are the pantry built into the left side of the kitchen, pull out counter, and cabinets reaching all the way to the roof. One amenity which isn't visible here (see floorplan below) is the floor hatch which will house the chest fridge/freezer. This saves an enormous amount of kitchen space as well as saving energy.

The floorplan was a most interesting exercise in doing more with less. One of the two most important differences between a tiny house like this and a more traditional RV is that the space is designed not to squeeze all the comforts of a traditional home into a mobile vehicle, but to provide the same spaciousness of a regular house but on a smaller scale. To that end, some elements are not included in this house such as a dining room, bathroom sink, and room divisions. The key to tiny house living is to find as many ways as possible to get double duty out of something (such as using the kitchen sink as a bathroom sink). One of the most brilliant solutions for the space was a rotating bookcase which turned to form a divider on the bathroom.

The building section makes clear how tight the constraints were on the building height. In order to keep the house beneath the maximum vehicle height of 13 feet, the bed loft had to be no higher than 48". After subtracting for the structure and the height of the trailer (which was about 22" tall), the downstairs area came to be slightly under 6 feet tall. This meant that the front door would have to be a custom built at a height of 5'-10". As explained in the construction page, the area over the bed loft was built with standard rafters because the bed loft would resist the outward force of the roof. However on the east side of the house we had to build scissor-trusses because the house would have felt too constrained with a regular ceiling.reference this in the construction page instead

In the South elevation you can see how many of these elements interact. The windows provide maximum sunlight within the height constraints. The roof pitch gives me an almost perfectly equal triangle in the bed loft for maximum structural strength. And finally the skylights provide an enormouse amount of light in a space which would otherwise feel cramped.

In addition to the passive solar design, the second most important factor in keeping this space as warm as possible is the use of an intelligent wall system. I began with the plan to keep the wall as thin as possible with regular 2x4 studs, a vapor barrier, and an interior finish. However after talking with several people including my friend Simon, it became clear that having an air gap would be worth the slight loss of interior space. As I spent time in the building, it was obvious that there would be enough room that the 1 1/2" of extra wall depth would be no great loss. As you can see in the image, each piece overlaps with at least 1/2" gap. So over the studs and insulation is the mylar sheet. On top of that is the lath at 8" on center. Then I have two more layers of 1/4" plywood over that to create a 3/4" gap. This provides a strong nailing surface and a thorough thermal break to prevent heat from transferring through it.

I started off with a very inexpensive trailer which would have been destined for the scrap yard given the state of rust. I had origionally bought it only for the axles which would have cost more than I paid for the whole thing. But after some discussion, I felt that the trailer could hold up to the estimated 4000lb load with some rienforcement.
As with the entire project, my main focus was (1) Reduce, (2) Reuse, (3) Recycle.

Before any work could be done on the house itself, the trailer had to be rienforced. This required buying some structural steel and welding it to the weakest areas of the chasis. At the time I was inexperienced with welding and needed help, but I soon picked up the basics and began doing my own welds.

By the time we finished the last welds, the trailer was noticeably heavier, but much stronger. Here is a shot of the trailer before the rienforcing at the back was installed.

I spent weeks traveling through industrial areas looking for the larger palletes which would provide lumber to fit my needs. Yes there was a Home Despot only one mile away, but then I would have been supporting capitalism and deforestation.
I eventually found some discarded 12ft long pallettes (this was the only pallet size that would provide the 8 foot lumber needed). I recovered roughly 3-4 regular pallets, and 3 heavier pallets made with 4x4 timber. In addition I found huge amounts of random lumber, much of it older than I was. This caused some trouble later on, but often a single antique stud was as strong as two studs fresh from the mill (link to wood age/strength).

Once the trailer was properly rienforced, it was time to start building the floor. I began by putting down a layer of bicycle tubes (see my page on uses for bike tubes) to thermally isolate the floor from the steel frame.

The floor started with sheets of 1/4" plywood which forms the bottom layer and protects the insulation from moisture and critters. This was bolted to the frame with the same re-used brackets that had been used to support the sliders on the boat trailer (again reuse is the key).

My assistant and I spent a few days pulling apart pallets, and building the floor. Engineering the floor structure had to accomodate two cavities. One for the wheel wells and another for the chest freezer. The two major issues that we had to work around were a)the need to build the floor with a cavity for the wheels because when the house was lowered onto them whe wheels project above the floor and b)building the framing around a cavity where the chest freezer would sit.

Once the floor structure was finished, we insulated it with standard R-21 batt insulation. I made the decision to run the bottom of the floor along the 'V' created by the boat trailer and so the outside edges have 3 1/2" of insulation while the middle has 8".
We laid regular plastic down on the inside of the insulation cavity to prevent air infiltration, and then on top of the floor structure we laid down building wrap. This protects the underside of the trailer from moisture infiltration and still allows moisture to escape if it builds up because building wrap is a one-way barrier.

Here you can see the finished floor with the openings for wheels and freezer. In front is a short covered deck which is why there is no insulation shown there.

In this photo you see the three walls built up with the building wrap attached. You may notice that the front wall is shorter, and that's because there will be a bed loft above this which is slightly lower than the total wall height. The rear wall has an opening for a window of yet to be determined size.

With the 'cold' walls up, it was time to build the south wall. This wall would be built in a 'timber frame' manner because nearly the entire wall is glass. Now the pallets which were made with 4x4 lumber come into play. Thanks to American waste, I have a full structure which is all recycled.
Only four pieces of wood were bought simply because we needed 20ft long boards for the top plate. Most houses use two layers of 2x4 on top of each other but I elected to save weight and material by running one layer continuously.

I was able to find a great deal on windows in new condition at The Rebuilding Center (love that place). These windows are well insulated, and provide an enormous amount of light. In this picture a volunteer is helping to put the final nails in place.

Now the first floor is completely framed and the door opening is created. It's finally starting to look like a complete building.

A very important problem presented itself when I saw these gaps between the north wall and the floor. This occurred because the trailer was still sitting on the wheels and the cantilevered walls weren't properly connected. The solution was to jack up the house along the length of the north wall and put brackets with some 3" long screws through the sole plate of the wall, the floor and the rim joist.

The bed loft was framed perpendicular to the wall because this would allow the loft floor to cantilever the weight to the inside of the structure. The upward force was countered by a 2x6 beam recovered from a very old building.

The antique beam was shaved and then cut to length. It took just a little sanding to bring out the historic beauty of the wood. The next step was to install dowels which would rienforce the connection. Dowels were necessary to withstand the tilting force from the cantilevered bed loft.

Here you see the fruit of 6 weeks of solid work. The four lower walls are finished and the bed loft is framed. The next steps will be finishing the outer walls, and building the roof. Until that gets complete, we attached building wrap over the top to keep me and the inside structure dry in case of rain.

Once the kitchen window was found (also at The Rebuilding Center) then the framing could be finalized and the siding cut out.

The first step in getting the window in place is to install a material called 'Protecto-Wrap' which is a highly sticky membrane which both secures the window and keeps out moisture.
It should be noted that this product is said to produce toxic gases when used with vinyl windows. The material is installed across the entire wall with overlaps on both sides and this is done all around the opening. This step is only necessary with windows that don't have 'nailing fins' such as the ones that came on the larger south windows.

This solution was to use scissor trusses. This system is a means of 'triangulating' the roof in a way that allows the lower part of the truss to act as a brace to prevent the upper wood members from deforming. Typically trusses are only used for large structures because of the cost and labor involved. However for this project, Luke was skilled enough and willing to build them on site.

Here you see the trusses fully installed. From here on, the roof will be built with normal rafters. Not only is the extra strength of the trusses unnecessary with the bed loft, but the trusses would have reduced the interior height of the loft.

The first step in building the framed roof was to connect the ridge beam. It's very important that a ridge beam be continuous from end to end. For this project the only 14ft piece that I recovered was a piece with several splits in it. Therefore we nailed 1x4 bracing on either side of the piece to form what's called a compound beam.

The interesting point about the rafters is that these pieces (like all of the framing) were salvaged. But in this case the salvaged wood was unusually old. As a result, the rafters are 2" x 4 1/4" instead of the more common 1 1/2 x 3 1/2". For the kind of forces we were looking at, a 2x4 would have been too weak, and there were not enough 2x6 pieces to complete the roof. With careful engineering the house has survived three moves and several wind storms with not a single problem. Big huge thanks to Matt Philips for helping us out for the whole day.

Once the roof was complete, we framed the west wall above the bed loft. It should be mentioned that we made liberal use of steel brackets and plates in many locations including the south wall, the rafters, and here on the west wall to provide a stronger connection.

This flashing is a long story. In order to get as much interior room as possible, the house was built to 8'-6" which is also the maximum allowable vehicle width. Therefore in order to have overhangs to keep the water away from the walls, the overhanging 'wings' would have to be removable. This was accomplished by creating the flashing in a 'V.' The wings would have a matching piece of flashing which slides into the gap created by the V.

In order to help prevent water from slipping underneath the flashing if the roof fails, I caulked the joint and then added tape on top of the joint. As with the skylights, I used high-temperature tape for the seam.

There was a long discussion about what would be the best roof for the structure. I was interested in either recycling the aluminum from another project, or using leftovers from a larger steel roof project. However a contractor insisted that a torch down roof would be necessary because a)it's the lightest material available b)it's the least expensive c)because the tar is melted directly to the plywood, it wont peel if the house is transported at higher speed. I talked this over with several people, but couldn't find a practical rebuttal. So I grudgingly installed this petroleum product on my roof.

One of the reasons that I was so reluctant to use this material is because it requires the roof to be heated to several hundred degrees in order to melt the tar onto the roof. This was by far the most unpleasant job of the entire project (partly because of steeply sloped roof).

At the same time that the roof was being installed, the skylights had to be set in place as well. Here the installation process is photo-documented step by step for you. Once the opening is cut, I installed several pieces of overlapping lumber to provide a rigid frame. These were connected with 2" staples to ensure a very strong connection.
The reason that I spent extra money (though not as much as you might think) on skylights is because they help create a stack effect to cool the house on hot days.

One of the reasons that skylights are prone to leak, is because of poor attention to detail.
One of these details is keeping water from backing up at the top of the skylight where the roof pitch meets the vertical wall of the window unit. Most contractors solve this by building up a smaller slope to each side of the frame. To simplify things, we just built up a 'cricket' that flows to the skylight's drain channels.

The next step in keeping out water is to build up flashing in a cascading pattern along each side of the unit.
An easier way for sure is to buy the flashing units that are available for skylights. These units however are not customizable and by building a curved transition we create an air pocket around the skylight. This acts as extra insulation which compensates for the large heat loss endemic in all skylight units.
After the flashing is laid down, the joints are caulked to prevent water from flowing back (through capilary action) into a joint.

On top of the caulked flashing, we installed high-temperature aluminum tape. Including the roof itself, this provides three levels of protection to ensure that water doesn't get in. I used the more expensive high-temperature tape because of the torch-down roofing. If you use another material, than you can use cheaper aluminum tape.

Most houses use full depth boxes which provide plenty of room for wires and outlets. However becuase we have thin 4" walls, the outlet boxes would leave no room for insulation. To prevent this, slender boxes were chosen which unfortunately meant buying new, but I figured that the energy savings were worth it.

Here you see the wiring being installed. Wiring isn't that tough to do, but it's important to keep the wire route as short and straight as possible because unlike extension cords (which are made of strands of copper) house wiring is made of three solid copper wires. This means that if it twists or bends too much in one place it can suffer metal fatigue. Wiring is fed through holes in the wall (5/8" for a single strand) which are drilled through the inside 1/3 of each stud. The wiring is stapled against the stud to keep it from getting twisted or tangled in the insulation.

Here you can see the process for installing electrical outlets. There are several points to keep in mind and it all must be done right or you could end up with a short. First you take a very sharp utility knife and cut the wire down the middle (between the positive and negative wires). Next you take a wire strippers and remove about 1" of insulation (there's a guide on the back of most outlets). Form the copper end into a loop and wrap it around the attachment screw (be sure it's wrapped in the same direction that the screw will tighten). Do this to both the positive (black) and negative (white) wires. Once this is done, connect the ground wire to the ground screw (the blue screw by his thumb here). If there are two wires going to the box than you need to crimp the ground wires.

Installing insulation is comparitavely simple as long as you keep a few things in mind. First of all the insulation has to go all the way to the edge of the stud or you'll have a gap. Some contractors will staple a handful of insulation to the stud itself before folding over the paper on top. In this picture I've pulled the insulation in half and stuffed one half behind the wiring and the other half in front.
Another thing to keep in mind is that you shouldn't depend on the insulation paper to form an air seal against wind driven cold. The paper is of very low quality and tears easily. The better option would be to use a vapor barrier on the inside of the stud surface. I plan to use repurposed mylar blankets to form a radiant barrier.

Here is what the insulation looks like when it's installed. Note the insulation above the window is an example of what not to do. This piece was wider and taller than the cavity and I had to resize it properly before re-installation.
Many of my friends have asked me why I didn't use something more sustainable like corn-based open cell insulation or recycled batt material. To that I have tag the cost. I did research the foam insulation and found that it wasn't possible for less than $1000 which was way out of my price range. The other recycled options were similarly extravagent.

In order to keep a building efficient, it's important to have an attention to detail. Any connection will have some gaps and caulking those early on before the area is covered up will prevent heat loss farther down the road.

One of the ways that heat is drawn through a wall is through metal connections that span the entire wall cavity called thermal bridging. In order to prevent this metal tie from transferring heat, I cut it at the line you see here. The other tie doesn't go all the way to the outside and so it wont transfer much heat.

Sealing the walls around the window is very important. This step is overlooked by so many contractors (the last house I lived in which was only 12 years old had gaps larger then 1/2" around the windows). This recycled rigid foam fills the larger gap between the rough opening and the window, then the whole unit is caulked on each side of the stud cavity. I looked through the window in the morning (east light) to see if any light shone through and found that my work was successful.

It was lucky that I happened to be installing insulation behind this wall at just the right time in the morning and saw sun streaming through the wall (the sun only hits this spot directly for a short window of the year). After going outside, I saw that the building wrap didn't extend below the gap between the stud and the floor. A little caulk on the inside and outside resolved the problem.

Another area where I found a gap which allowed air to enter was near the front door. At this point, the building wrap also didn't extend to the floor because of the window. The gap between the two sole plate pieces was so great that I was able to photograph the interior through it. I spent time filling this with insulation and caulking the gap inside and out.

The next step that I completed was the sealing of the air gaps around the windows. I started off by filling the cavity with insulation. Because while caulk will seal the gap against air infiltration, that wont itself provide much of an R-value. However by filling the gap with insulation and then adding caulk, the best temperature control is achieved.
Here you can see the finished caulking job. I made in some places two or three passes to fill the large gap between the framing and the window.
Note: In retrospect, it would have made more sense to cut some thin pieces of wood and install those so that the caulk only had to be 1/4" or so.

When caulk is being applied to large gaps, there is often a material called 'backer rod' applied to the gap to keep from using excessive caulk and to provide a convex surface for the caulk to sit (ref). Since backer rod costs money and is made from toxic material, I found a different method using bicycle tubing (yup, there's 101 uses for bicycle tubes). The tubing squeezed into the gap just fine and provided a nice surface for the caulk to sit against and being rubber it provided some amount of insulation.

In keeping with my values of (first) reduce, (second) reuse, and only then recycle. I recieved a most excellent idea for creating a vapor barrier with recycled mylar. I went to the Portland Marathon and collected mylar blankets at the end. I washed and dried dozens of these blankets on sunny days. This saved me the high cost of buying sheets of mylar.
After attaching sheets across the entire wall, I began tacking 1 1/2" strips of plywood which does two things. First it helps secure the mylar to the wall, and second it creates the first part of the air gap. The importance of attaching these pieces so far away from each other is so that there's more open space in front of the mylar. Any place that the mylar rests directly against the sheets, it ruins it's effectiveness in reflecting heat. So the larger the open area, the more useful it is.

Here you can see each stage of the sealing process together. The insulation (1), the mylar blankets (2), the plywood strips (3), and the finished wall paneling (4). I used mediocre plywood in this area because the kitchen cabinets are going to cover the walls.

During the winter I put in paneling behind the kitchen and living area. So how does one cut and install plywood in a tiny house while it's raining outside?
Very slowly and with lots of tetris-like manuevers.
Here I'm creating holes in the panel for electric outlets next to the chest freezer which is yet to be put into place under the floor.

After many hours of picking through the plywood that I salvaged, and finding the right size pieces, the bed loft is finished. I haven't decided whether to put anything over this or leave it multi-colored as it is here. But with a coat of paint it will be ready to sleep in.

My close friend Brian works as a carpenter. He was generous enough to take time to build me a Maple countertop out of some leftover material that I was able to find.

Here you see the counter installed. On the left is the beginning framework for a full-height pantry and on the right is going to be a standard floating cabinet.

The patchwork look of the walls is due to the use of discarded plywood paneling. The worst looking pieces were installed where they would be covered by storage and the best looking ones would remain visible.

To make using the kitchen easier, I carefully made a hole in the backer board of the counter and installed an outlet for use with my blender and hotplate.

To support the upper cabinet, I took some damaged oak and ran it through the table saw until I was left with a nice piece of trim. This was attached to the wall at the base of where the unit would go.

Here the lower shelf of the cabinet is being put in place. The cabinets were not bought from a store and so they did not come as a unit. I built them piece by piece in place from whatever reclaimed material was good looking enough to use in a kitchen.

I had gotten access to some LED light panels and decided to make them into task lighting. You can see here my technique for turning them into under-cabinet lights. These lit up the counter marvelously and the cabinet didn't block the light.