Building a House of Steel

Forget straw, sticks and bricks, this home will be made of steel and though it may not be quite as cool as straw, so far it looks like it will measure up to be a darn sturdy home. It goes without saying that this is the most critical step to get right and Chris spent innumerable hours on research and design to ensure we ended up with a sound and feasible solution for this house. Each section has been quick work to measure, mark and cut and super solid (in a good way) upon assembly and we are at the stage where only the roof remains to be completed. So yes, I have been negligent in the sharing of this process but remedy that today I shall!

Now I can’t help myself but emphasise that despite the tremendous amount of study, neither of us are in a position to provide an expert opinion on this structure. So whilst I am happy to share our process in brief detail, if you are considering building your own steel frame, I would encourage you to treat this simply as another snippet of inspiration.

Alright, serious business out of the way, let’s get to it.

Why Steel?

Yep, if you have ever researched building a tiny home, you will likely have come across the many, many, discussions around tiny home materials. It’s rather overwhelming and let’s be honest, my uneducated sentiments won’t be adding anything beneficial to the plethora of opinions out there. That said, it’s a question I am often asked, so I will share the thoughts behind my decision but will let you guys do your own digging for the pros and cons. (Have fun!)

At the time we were investigating frame materials, and it was a long time ago now, it seemed most crucial to reduce the overall weight and crunching some numbers suggested steel could be significantly lighter than timber. (People will argue this isn’t always the case with tiny homes, and true, it will all depend on the gauge of your steel and the design of the frame.)

Additionally, this choice presented me with the chance to familiarise myself with metal, a material I had never really worked with. It seemed daunting, cold and unforgiving and I admit to championing timber over steel for quite a while. However one of the key reasons I wanted to build this house was to learn, and as I would already be working plenty with timber, it really was a perfect opportunity. True, it would be more expensive than timber, but to broaden my skill set strikes me as money well spent, so I resolved to give it a go. As for the environmental impact? Well, this is one of those decisions you could argue both ways, and honestly, I don’t know, or have, the answer for this one. But I have a lot of thoughts on the matter so we will definitely delve into that in another post.

Where to Start?

As Chris handled the technical side, the frame aspect for me really started when we began looking into the necessary tools, and after some investigation, it was determined that it would be a good idea to invest in a cold cut metal circular saw. See, because metal expands when it’s heated, a regular circular saw can cause friction or binding, making the saw work harder. A cold cut saw transfers the heat generated from cutting into the metal chips, and this keeps both the tool and material cool. I ended up with a Makita Metal Cold Cut Circular Saw, chiefly because I already had a battery from my Makita drill and driver, but too because we could use it for both the frame and cutting of the corrugated steel cladding.

Happily, it turns out this little saw is brilliant- it is super lightweight, quick and just so easy to wield. Overall we’ve both been very impressed with its performance. I was sceptical as to how much I would use this tool, especially considering my partiality for timber but with this, metalwork seems much more approachable, and I now believe the use of steel in jigs and such as much more likely. [Though a quick side note, if you notice the blade isn’t spinning, just check that it’s tightly attached- any looseness will prevent it from working.]

To cut out the slots for the studs to fit through we were acquainted with a drill fitting called a Nibbler. Cute name, right? Admittedly I kind of hated the Nibbler to begin with, I just could not seem to get the hang of the little beast. Finally, I got it, and it quickly became my favourite step of the process. It works something like a hole punch, rapidly punching small crescents in the steel. You can spend a fair bit of money on these fittings, but in this instance, we went with a budget Craftright nibbler and so far it has served the job really well!

Get Building

Chris designed the frame so we could build it in pieces and assemble it on the trailer once we had all the parts. Seeing as I had been imaging struggling to build the frame attached to the trailer, I was relieved by this far less difficult/awkward method.

Overall there are thirteen pieces of the frame, and though we were slow at the beginning, the last few we chugged out in 3-4 hours each. I finally managed to remember to take some process shots as we built the end bathroom wall, one of the largest pieces. It’s not quite finished as we won’t be attaching the top track until the four walls are fixed together, but you can certainly get the gist.

After finally getting stuck into some building I returned to my lighting research with renewed energy. Inspired to tackle my work with a slightly more hands-on approach I pulled out a couple of light bulbs from our hallway cupboard to have a look for myself. Funnily enough, the cardboard boxes proved the more interesting and soon I was reading the information the manufacturers consider major selling points.

bulb

What is a watt?

Watts measure the energy consumed by a bulb.
During the dominance of incandescent’s, watts would be advertised as the measurement of brightness, yet when new lighting technologies were introduced this could no longer be a sound gauge for consumers. This is because halogens and LEDs use less wattage to create the same amount of brightness. For example; a 100-watt incandescent bulb provides 1600 lumens, whilst you only need a 22 watt LED to achieve the same result. If you used a 100 watt LED, you would be looking at an outdoor floodlight!

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Flipping the box over I found a table detailing the specifications of the globe- voltage, frequency, colour, and output. I break down each one below:

bulbvolt

What is voltage?

Voltage measures the pressure of an electric current.
It is suggested to think of voltage through the terms of water tanks. The water stored in the tank is the charge. The pressure of a connected hose represents voltage. The more water in the tank (battery), the higher the pressure (voltage). As the tank is drained the pressure decreases, just like a torch dims as the batteries run low.

Mathematically, a volt is the amount of joules per coulomb.
Or in English, the amount of work per group of flowing electrons.

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In the case of my lightbulb, the voltage is 240V. As mentioned here, electricity enters your home at 240 volts. When the lightbulb is connected to the home’s circuit (240v) it should deliver the advertised lumens. If you connect this bulb to a lower voltage it will continue to work but will be dimmer than advertised. If you use a bulb recommended for a lower voltage, the light produced will be brighter, but the globe will have a shorter lifespan.

What is frequency?

This is the invisible flickering of a light bulb connected to AC- it is the pulse of the electricity pumping through the bulb. A frequency of 50/60 cannot be detected by the naked eye. However, if a frequency is too low the eye will detect the flickering which can cause headaches and eye strain. To be honest I don’t really understand the role frequency plays, but for now, that explanation will do.

What is colour temperature?

Colour temperature is exactly as it sounds, the colour of the light. It is measured in Kelvins. The higher the Kelvin (K) rating, the whiter the light will be. 1000- 3500k produces warm light, 3500- 4100k is neutral, 5000k up is considered cool. This scale remains the same for all lightbulbs.

1900k is candlelight
2000k or under will give a dim soft glow- good for ambient lighting.
2000 to 3000k is best for living rooms and bedrooms as they give a soft white glow.
3100 to 4500k for kitchens/workspaces, good for task lighting. (Bright bluish daylight too harsh for home ambient lighting.)
4800k direct sunlight.
6000k cloudy sky.

My lightbulb has a temperature of 2800k, meaning it produces a soft white light.

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What are lumens?

Lumens is the measurement used to represent how bright a light is. It indicates the total light emitted, no matter the direction.
Lux is the unit used to measure the output of light in a given area, so 1 lux = 1 lumen metre squared. It is a measurement of the amount of visible light and intensity of the illumination. The centre of a lamp beam is where the light intensity is the highest.

Lumens and lux come into play when planning the lighting of your home when considering Ambient and Task lighting.

Ambient lighting should radiate a comfortable level of brightness and is considered the room’s ‘natural light.’ This is generally achieved through the use of omni-directional (light in all directions) lamps. Downlights will pool light on surfaces so should only be used for task lighting. They are not successful at achieving general illumination. Up to six downlights s would be needed to achieve the same result of an omni-directional light. Light shades can absorb almost half of your light so choose carefully.

Task lighting provides concentrated light for an area of work or reading. It has to be brighter than the ambient lighting to ensure contrast. Lamps and track lighting can be used if the direction needs to be changed. Under counter kitchen lights are used as fixed directional lighting. Task lighting needs to be free of glare and shadows, but bright enough to avoid eye strain.

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Lighting completes the trio of topics I did not want to think too much about, but unlike plumbing and electricity, I’ve found it difficult to kindle any particular enthusiasm for it. After a handful of false starts, I have decided that I need to cut to the chase with this one, to the one aspect that has perked any interest: Radial Circuits. It came to my attention by means of one very helpful and well-informed John Ward. (Here is his YouTube channel for all sorts of electrical explorations). I did grudgingly dedicate a Google-search session to the humble lightbulb itself. So before we get to the fun, here is the hum-drum.

Incandescent Lightbulbs

The role of the lightbulb is to convert energy into light energy. The traditional light bulb, or rather an Incandescent lightbulb, was the first of its kind and it hasn’t changed greatly since it was invented in the late 1800’s.
The glass bulb is capped with a metal base. This base has two metal contact points which connect to the tungsten filament (a very thin coil of metal wire with an incredibly high melting point). When the light bulb is connected to an electrical current, the electrons in the copper collide into the atoms in the filament causing them to vibrate. This vibration heats the atoms to approximately 2000+ degrees Celsius, causing them to glow and thus giving us light. The filament is sealed in a glass bulb to keep oxygen away from the wire as without this seal, the tungsten would burn up within a couple of minutes.

[This video captures the mesmerising manufacturing process. Seriously, treat yourself. It is super satisfying].

Though immensely popular, incandescent light bulbs are incredibly inefficient; approximately 90% of the energy consumed by the incandescent bulb is used to heat the filament alone. That means only 10% is used to create light, the sole purpose of a lightbulb in the first place. This considerable flaw has seen the development of a number of other light bulb designs, each with the goal of higher efficiency.

Halogen globes

These are very similar to Incandescents except that the bulbs are filled with the gas Hydrogen Bromide. This gas captures and returns any stray, evaporated tungsten atoms, prolonging the life of the filament. It also keeps the glass clear.

Fluorescents

Glass tubes are filled with gas and capped at each end with an electrode (electrical conductor). When connected to an electric current, electrons knock into the mercury atoms in the gas. This excites them into emitting both visible and ultraviolet light. The insides of the tubes are coated white so that the ultraviolet light can be absorbed and remitted as visible light. This also prevents us from being exposed to UV rays.

Light Emitting Diodes (LED)

Before we launch into LEDs I will note that I spent far too long researching diodes and how they work, especially considering I had set out to avoid longwinded research into lighting in the first place. Worse, I still don’t believe I truly understand how they work- despite struggling through numerous long-winded YouTube videos. That said, I need proof that I did something with my morning, so I have included it anyway. Please feel free to skip the next three paragraphs because to accept the diode as a light emitting chip is most likely more than sufficient.

A diode is a semiconducting electronic device that has two terminals, one negatively charged (cathode), the other positively charged (anode). It has low resistance in one direction, and high resistance in the other, meaning it will only allow electricity to flow in the one direction.

Semiconductors are materials that are typically insulators; meaning they don’t encourage the flow of electricity. They can, however, be turned into conductors through a chemical process called doping. Extra element atoms can be added to a semiconductor material like Silicon, giving it additional electrons. Materials altered in such a way are known as N-type (negative type) and carry a negative electric charge.
Similarly, you can add atoms which take away electrons, leaving ‘holes.’ When this occurs, the material becomes P-Type (positive type.) These holes carry a positive electric charge. Diodes are created when an N-Type and a P-Type are paired together.

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The border between the P-Type and N-Type is known as the P-N junction and it is this that keeps the two sides separate. Without an electrical charge, only the electrons and the holes in the center can recombine. This creates a depletion zone where there are no free carriers. It also creates an electrical field. Only when the diode is connected to a battery voltage higher than the electric field can the N-Type electrons gain enough energy to cross the junction. This shrinks the depletion zone and allows the electrons to fill the holes of the P-Type, creating light (photons). The key thing to note is that the battery must be connected negative to negative/positive to positive, otherwise the depletion zone grows larger and there will be no light.
(sigh)

In conclusion, diodes in LEDs create light. They are an incredibly efficient way of doing so, using only 10% of the energy used to illuminate an incandescent bulb. The diode itself only amounts to a very small semiconductor chip, known as the ‘die’. These can be cased inside tiny bulbs or mounted directly onto surfaces.

What are the different LED chips available?

LED DIP (Dual In Line): This is the traditional LED light with a tiny bulb (capsule shape top). The hard plastic (epoxy) cap encases a DIP chip and has two parallel connecting pins which act as the anode (longer leg) and cathode. They produce approximately 4 lumens per LED.

Surface Mount LEDs: Smaller and more efficient than the Dual In Lines, SMD’s can produce 50 to 100 lumens per watt. The chips are welded onto circuit boards and used across numerous applications (lamps/signage/car lights/computer monitors). SMD chips can have more than two contact points and up to 3 diodes, each with an individual circuit. This means a red, blue and green diode can be used, allowing the creation of almost any colour.

Chip on Board LEDs: COB’s are the newest application of LED chips and allow for 9 diodes or more. They cannot change colour like SMDs but can produce more lumens with less energy so are used for floodlights. It produces a minimum of 80 lumens per watt.

Evidently, discussion of watts and lumens demands a post of their own, but for today I am so very done. Plus, Harry and Meghan’s wedding is about to screen! Priorities!

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So the plan was to dedicate this afternoon to expanding my knowledge on electric currents and the seemingly complicated business of volts… but alas somehow along the line I instead became fixated with learning all one could ever want to know about copper! What started with a simple search into this metal’s excellent conductivity, sprouted into a beginning-to-end understanding of how copper, and in turn copper wiring, is produced…
So maybe I somewhat wasted a precious afternoon of research, HOWEVER, at least I’ll have a sliver of very specific knowledge should I ever need to influence someone of my extreme cleverness. (Rest easy, below is the abridged version.)

Mining Copper

Copper (Cu) is found in ore, (rock containing mineral or metal), which has been mined from the earth in open cut or underground mines. [Open cut mines are those immense pits which are ‘step’ dug into the earth, extending deeper and deeper as the orebodies closest to the surface are depleted.]
The ore is broken, typically through explosives, and brought to the earth’s surface. It is crushed into boulder-sized rocks via a primary crusher, then transported in haul trucks for processing.
There are two types of copper ore, Oxide (less concentrated, but cheaper to process) and Sulfide (less common, but with a higher concentrate of copper).

Oxide is processed in three steps which I will very briefly and rudimentarily touch on. Basically, the first step sees the ore sprayed with a chemical solution that dissolves the copper out of the ore. The pooled copper is then mixed with two ‘unmixable’ liquids, separating any impurities. The copper mixture is then positively charged. Very thin copper starter sheets are dipped into the mixture and left to soak for 10 days which plates the sheets to a thickness of 1 inch. These sheets (cathodes) are now at a purity level of 99.99% and can be used as a raw material.

Sulfide is ground to a fine sand before being added to a liquid to create a slurry. Chemicals are added to the water, making the copper particles waterproof. Air is blown into the solution to create bubbles which rise to the surface with the collected copper. The froth is then skimmed from the top. This is poured into thickeners, which sees the bubbles burst and the copper sink. Excess water is filtered out and the copper is sent to the smelter, a whole system of furnaces. [This part gets pretty long-winded, but if you’re interested I highly recommend this super fun video.]
In short, you end up with copper sheets to be melted and cast into cakes used for plumbing parts and sheeting, or rods used for electrical wiring.

Copper Wiring

In order to turn the copper into electric wires, there are a few further steps involved.
Copper rods are run through a machine which stretches the metal into a thin strand of wire which is wound onto a large bobbin. Bobbins are loaded into a stranding machine and the ends of two bobbins are ‘cold welded’ together. This machine winds seven wires together, forming a low voltage electric conductor (<1000 volts). These are the wires used to run electricity to your home. The wire is insulated and colour coded with PVC to prevent electric shocks. Multiple wires can be welded and insulated together to create a higher voltage. This somewhat dated but helpful video captures the process.

Why do we use copper in electrical wiring?

Here is where I had to take a side step from copper to briefly brush up on my high school science. I really didn’t enjoy science at school, and honestly cannot remember learning a thing! I’m not sure why I had such difficulty with it, I think I just wrote it off as something I’d never understand. Looking back, it’s a crying shame because it is so darn interesting, especially when one considers…the atom!

What is an atom?

Atoms are the smallest particles that exist. They are the very first building blocks to the make up of everything on earth: plants, tables, humans etc. An atom is the equivalent of a letter in a word, in that it is the smallest unit of a word.

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A molecule is the equivalent of a word. So, how you would put together different letters to create different words; different atoms group to create different molecules.
For example: take two Hydrogen atoms and an Oxygen atom (letters) and you get the compound molecule Water (word). Or, take 3 Hydrogens and 1 Nitrogen and you get Ammonia.

Copper is an element, as opposed to a molecule. An element is a substance made entirely of one type of atom. There are 118 elements and these are captured in the periodic table.

An atoms ‘body’ is made up of three particles: electrons (negatively charged), protons (positively charged), and neutrons (neutral). The protons and neutrons group together to form the nucleus, and the electrons ‘hover’ around the nucleus, grouped in orbital shells. An atom is neutral since the total number of electrons is equal to protons. As the protons have an equal amount of draw to the electrons, the electrons can’t ‘run away,’ keeping the atom together. Scan 77

An atom can have a number of shells, but it is the number of electrons in the outer shell (Valence electrons) that determines the conductivity of an atom.. The lower the number, the higher the conductivity. If there is only one valence electron it will receive most of the energy when two atoms knock together. If there are multiple each electron will only receive a fraction of that energy. Copper atoms contain a single valence electron, making it a perfect conductor.

Creating an Electric Current with Copper:

When exposed to an electric field, copper atoms knock into each other creating a strong repelling reaction. This enables the valence electron to break free from its bond with the atom, allowing it to move around freely. It can now travel through the physical structure of the metal.

To create an electric current, the movement of these free electrons needs to be organised. Batteries or generators can organise electrons to move in one direction, creating a direct current (DC).
Power stations organise electrons by pumping electrons 100 times a second. Instead of moving along in a single direction they remain in place, taking one step forward and one step back, constantly changing direction. This creates an alternating current (AC).

More on this and how it applies to my tiny home next time!

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SIX BY TINY

Shelter

Building a House of Steel

Why Steel?

Where to Start?

Get Building

What is a watt?

What is voltage?

What is frequency?

What is colour temperature?

What are lumens?

Incandescent Lightbulbs

Halogen globes

Fluorescents

Light Emitting Diodes (LED)

What are the different LED chips available?

Mining Copper

Copper Wiring

Why do we use copper in electrical wiring?

What is an atom?

Creating an Electric Current with Copper: