Wiring a Tiny House

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We were unable to make use of much in the way of recycled materials for the wiring. I did go to the Habitat for Humanity ReStore in search of outlet and switches, but elected to use newer fixtures with safety features.

**Disclaimer** I am not an electrician and am giving no advice (no good advice) on the subject. You probably shouldn’t wire your house by yourself. But for your entertainment…

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I decided to go with 12 gauge wire to cut down on voltage loss and to allow for future upgrades. I was somewhat daunted by this aspect of building before starting, but as I watched a few DIY videos I became more at ease. After completing the electrical work I would say that it was one of the easier jobs thus far.

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I bought a small (6 slot) standard breaker box and drew a diagram of our outlet, switch, fan, smoke detector and light fixture arrangement based on our floor plan. I ended up using 3 circuits, 2 of which are GFCI protected. We have 3-way switches to allow us to control the kitchen lights from both levels, dimming LED recessed lights in the living room, tamper resistant outlets throughout and 2 outdoor outlets.

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A few tips:

I feel like the heavy duty plastic boxes are worth the extra money; the cheap ones just seem too flimsy.

The tamper resistant outlets are a good option if you have or plan to have kids.

The good wire strippers are worth the money. Klein makes a set that strips Romex as well as 12/14 AWG wire and cuts the wire with ease.

3-way switches aren’t all that difficult to wire and they will make your life easier in the long run.

GFCI outlets are cheaper than the GFCI breakers and do the same job. We put one in the kitchen and one in the bathroom

Siding a Tiny House with Up-cycled Fencing

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This may not be the easiest way to produce a pretty exterior for your home, but we were set on using recycled material and we’re happy with the results.

We happened to be in the city and with some time to spare we decided to look for lumber we could use for siding. We had not decided whether to use shingles, ship lap or board and batten as we began perusing Craigslist. We somehow came to the idea (I can’t claim that this was an original thought because I truly don’t remember) to find old cedar and/or redwood fencing – a cheap and weather-resilient material.20141028_16465120141103_174134

The fence panels were old and weathered. It was clear that planks and whole panels had been replaced over the years. As I started removing planks from the cross-members, it became evident that not all of the wood was usable. I cut off the splintered and knotty pieces and began screwing the mismatched lumber to the exterior. It all came together much nicer than expected as a mosaic of color unfurled.

What I expected to take 4-5 days took nearly 3 weeks to complete! I took my time ensuring the edges were flush and the trim fit nicely. We ran out of fencing material and settled on corrugated metal for much of the north and east sides of the house. I plan to use muriatic acid to remove the tin coating and let the steel find a nice patina, but that can wait. We will also be placing a clear coat over the siding to protect it from the elements.

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In summation for $180 in lumber, $20 in screws and $80 in corrugated metal we made the exterior nice to look at. We used only a skill saw and cordless drill for this phase of the project and a healthy dose of patience. Now it’s time for wiring…

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Roofing a Tiny House

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After doing some research when we first started building, we agreed on metal roofing. Metal is easily installed, completely recyclable, long lasting, and it can be used for rain water harvesting without concerns over carcinogens. We found a local company that would supply 26 gauge galvanized steel roofing for a reasonable price as well as a “drip edge” flashing that would serve our runoff, as well as our facia needs.

After placing the 1/2 ‘’ OSB over the roof framing, we installed 1-1/2’’ polyisocyanurate (Often called “polyiso” for short, or generically “foam board”.) insulation. Polyiso is commonly regarded as the most eco-friendly option amongst the foam choices. Installation is simple as the boards are the same dimensions as the sheathing and our roof dimensions (8.5×24) with no peaks or valleys made the entire roofing portion very simple.

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Over the polyiso, we placed a layer of water proofing superior to felt paper. The product we used is manufacture by Grace for prevention of ice dams in metal roofs near the toe of slopes. We elected to cover the entire roof in the product due to its reputation as a water barrier. The underside of the product is an asphalt-like layer that will adhere to anything and forms a strong bond to the polyiso.1017141340

Placing the drip edge and metal roofing panels proved very easy and was finished in only a few hours. As with everything else, the panels were screwed on, with considerations for wind and highway travel. The panels went together seamlessly and we have the added insurance of the weather barrier beneath.

Our roof is designed to be impermeable. We have no vents, chimneys or etc. and we designed it this way for simplicity and peace of mind. Houses must however be given opportunity to expel moisture that builds up at the roof interface. We will achieve this with soffits (vents) installed in the underside of our south, east, and west roof overhangs (the roof is tilted to the north).

Sheathing: The First Walls on Our Tiny House

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Sheathing provides lateral rigidity and a weather barrier to the exterior of a home. It also provides a clean surface over which to apply siding. We used ½’’ OSB (Oriented Strand Board, I had always just called it particle board) over the walls. We also had about 180 square feet of MDF siding that we used on the north face of the house as sheathing. We were given this siding as a bonus when we purchased our floor joist lumber from a gentleman on Craigslist and as it was stained and generally unattractive (albeit unused), we decided to use it as sheathing.

Sheathing is generally not a complex process. I was tipped that we should allot a 1/8’’ spacing between sheets as OSB can expand/contract with weather. Due to our ample window coverage, we were not able to use precisely 24’’ OC spacing for all studs and therefore were required to make many more cuts of our sheathing that is generally required. This still did not greatly increase the difficulty of a fairly simple process.

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Sheathing is also the time to find out just how square your framing job turned out. I walked around the house and checked myself with a framing square and carpenter’s level before I began sheathing. I did find a few minor adjustments to make while placing the OSB (OSB and plywood are made by machine and are near perfectly square. Assuming your framing is correct and there’s a problem with the sheathing is like blaming your calculator for errors).

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Framing for a Tiny House

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As with the floor, we decided to frame the walls with 2x6s for added rigidity and space for insulation. The 24-inch spacing allows less thermal bridging (conduction through the studs) than 16-inch spacing as is necessary with traditional 2×4 framing. The increased spacing also reduces the weight difference that might otherwise pose a problem for those building on a trailer.

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Framing is actually simpler than I expected. I decided early on that screwing the studs together would be necessitated by the torsion stresses the house would face in highway travel. We plan on being more sedentary than most tiny-housers, but we’re building with other future owners of the home in mind.

Before we began designing our framing diagrams we purchased all of our windows. Most of the windows came from the Habitat for Humanity’s ReStore. They have some great building materials far cheaper than even Craigslist usually offers. Our design is intended to utilize passive solar for chilly high elevation winters with our south-facing wall containing 4 windows (approximately 30% glass by surface area). The sliding glass door that we purchased, as well as one of our larger windows were both already jambed and we were able to simply use those dimensions for framing design. For the remaining 6 windows we added 1 inch on all sides to a lot for framing in our designs.

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The walls came together more quickly than I had anticipated. Using a cheap (I believe it cost me $100-$120) battery-powered saw and drill set, the walls were up in a week. I was continually waiting on my batteries to charge and I would strongly recommend a traditional corded circular saw or miter saw for this part of the project. I ended up buying one after framing and utilized it for sheathing.

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Our roof framing is quite simple and consists merely of 2x4s placed across the 8’ wall span at 24’’ OC. Upon sheathing the roof, this is more than enough capacity for me to wall on without any noticeable “give”. The roof overhangs the wall framing by 3’’ on both sides and 1’ at each end providing rain protection at the entry way and over our utility space.

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How to Set up Your Very Own Off-Grid Solar System

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Please do not make us your primary source for everything solar and the electrical part of the process. We are learning as we go and sharing that information.

When considering solar, it seemed like a no-brainer. Buy some panels, some batteries and maybe one or two random parts then put them all together and plug in to our travel trailer. Pay a bit upfront, but the government will hopefully help us be green and sustainable, and the panels will pay themselves off after 5 years and still have 15 more years of life, right?

Wellllll…. (frown-ish face), not quite. Looking back, do we regret doing solar? Nooooo, I think we would have just waited to buy everything and install them until after we were settled in because money has been tight. I suppose living on a combined salary of $30,000 (gross) and building a tiny house will do that to a couple. So below we outline the parts we had to buy, costs of everything, and a general how to do it yourself.

A. Costs (including taxes)

$860  4 x 280-watt solar panels (picked up from a warehouse in Phoenix)

$1200 8 x 225 amp hr 6v Trojan batteries (also picked up in Phoenix but at a battery shop)

$1050 1800-watt Pure Sine Waive Inverter (Amazon- pain in the butt to get because everyone was out of stock)

$600 Midnite Classic 150 Charge Controller (Online Solar Supplier)

$30 2 Gauge AWG, 30 ft. Wire (Amazon)

$45 9 x Plastic Totes to store batteries and other equip. (Dollar General)

$15 4-Way Solar Wire Connector (Amazon)

$20 Misc. Fuses and Switches (Lowes)

$80 Treated Lumber and Hardware for Homemade Solar Panel frame (Lowes)

$25 15 Amp Extension Cord (Amazon)

TOTAL = $3925 

B. Off-Grid Solar Basics

Basic Components: solar collectors, charge controller, batteries and inverter

1. The average DIY solar set-up is arranged to change the tilt of the panels twice a year, thus achieving just over 70% efficiency. Newer, very expensive 2 axis sun tracking systems can achieve 100% efficiency but at a great cost. Your panels in the Northern Hemisphere will be tilted, approximately, to the south at an angle of your latitude +15 degrees in the winter and your latitude – 15 degrees in the summer.

2. The electricity generated by the panels will be fed through the charge controller, which supplies the required voltage to your battery bank, thus maintaining your batteries at an appropriate voltage.

3. The battery bank receiving a current from the charge controller should be maintained at 80% or more capacity for prolonged battery life. Battery banks should be sized accordingly.

          For instance, we use an average of 2.5 kwh per day and our battery bank is capable of storing 10.8 kwh.

4. The current from the batteries is fed to the inverter. We chose a pure sine inverter because it is capable of powering anything you might plug in to your typical household outlet. It is more expensive so your particular household set-up may not require this. The inverter changes the voltage from, what is in our case, a 24 volt battery bank to our household 120 volts. The inverter also converts DC to AC (AC being what you need for typical household electricity).

5. Also keep in mind that, as of 2014, you get 30% tax credit for what you spend on solar from the federal government, and Arizona shells out another 25% so we will be getting back 55% of what we paid for the system. Save your receipts!

C. Tips and Help

– Once you’ve decided to design and build your own off-grid solar system, the first step is to size your system appropriately. You can do this by looking at your electricity bill and finding your average electricity usage. A handy tool in this process is a Kill-A-Watt meter. Using this, you can assess the energy uses of individual appliances.

      – After sizing your system, the first consideration should be your battery bank. The bank is where your electricity is sourced from and must           be sized correctly before considering your solar panel needs. Before you get started, you should learn a lot about batteries. Trust me, it is             worth your time and it will save you money in the end.

      – After you’ve done this, you’ll need to pair that with an adequate supply of solar power for charging. Your solar panel array will need to be           sized according to the formula: X AH * 14.5 (assuming a 12v battery bank) volts charging * 0.05-0.13 (depending on your usage) charge rate         * 1/0.77 system derating = Y watts of solar panels

– It’s time to get educated about how electricity works. Remember the terms “series” and “parallel”? How about “amps,” “watts,” “ohms,” and “volts”? You need to become very familiar with all of these terms before you get started.

     – Want some Forums? The one below is very helpful:

           Northern Arizona Wind and Sun

 – Want more information or have questions? Feel free to email or message us!

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Initial Reactions to Our Tiny House Plan

“I feel claustrophobic even thinking about it…” – My mother

“That sounds… nice…” – Dave’s mother

“Well, good thing not to burden yourself with debt. Especially with your salary being as it is.” – My father

“We hate you. We have been wanting to do that!” – Close friends

“Want to help us build a trailer and a tiny house?” (out of the blue text sent to friend)

“Heck yeah!” (immediate response)

You may get a little idea of how our family and friends responded to our great idea from these few posts. The idea of tiny houses occurred to us while we were discussing possibilities on our honeymoon on the tiny island of Montserrat. I was on Facebook scouring the newsfeed for something interesting to take my mind off of my mosquito bites when I saw a post about tiny houses from a close friend. After showing Dave, an idea grew over the course of our trip that we are now pursuing. Is it possible to buy a small piece of land and live in a travel trailer while Dave goes back to school, and I continue teaching? Would it furthermore be possible for Dave to build a Tiny House as his job when he isn’t doing schoolwork if our friends help out?

We are hoping so.

The plan:

  • Find a cheap plot of land
  • Find a travel trailer we can live in for the year and a half we plan to build this tiny house, or green casita in our case
  • Enlist help from an engineer friend 2 hours away for building a trailer and doing much of the work in the house
  • Also get help from another friend who has some framing and construction experience
  • Find as many cheap, reusable materials as possible

As you can see, we have accomplished some of these things already during the 3 week road trip we just took because we didn’t want to pay rent (that story in the next post). Luckily we had some money saved up to get started. So far we have spent: $4200 for a .2 acre lot near where I work and somewhat close to town. Why is it so cheap? It doesn’t have city utilities yet so we are looking into passive heating and cooling, a solar system for electricity, reusing gray water, and taking the trailer to dump the black water every other week. We also purchased a ’99 Cougar Travel Trailer, 21′, from a man posted on craigslist. We bought it for $3,800 but expect to put new tires on it, so it will probably cost us $4,000 after all is said and done. Besides the tires, it was completely checked out before we got it from electrical to plumbing and sealing, so we feel pretty good about it as of right now. Total spent as of right now: $8,200

We also expect to spend around-under $3,000 for solar panels, batteries, and a control. Details on how we put everything together is also to come. I hope to narrate our plans but also make the “How To” part very straightforward for those of you who don’t want to listen to my blathering.