How to Build a Healthy Tiny Home
What makes a healthy tiny home? Or any home for that matter?
I’ve realized throughout the process of building my own house that there aren’t many resources available to help people and builders design and build tiny houses that are created from the trailer up to be high performing with chemical-free materials and proper ventilation. They must have continuous fresh air to keep the inhabitants breathing clean air, since tiny homes are built so tight. For the most part, tiny homes are built on trailers, which makes them mobile and therefore they should function in various climates. However, the conventional way of building tiny houses doesn’t take into consideration the health of the tiny house dwellers, the impact on the environment, or the functionality paired with longevity of the tiny home. As a result, many tiny houses are becoming “sick” and inundated with mold growth, off-gassing of toxic chemicals from the building materials into the breathing space, and dust (and dust mites), which can transfer through the wall system. They don’t perform at the level they are capable of due to the use of conventional materials and building practices. If the materials and building principles were to change in a more “green” direction, with true building science backing it up, tiny houses could actually have the integrity that they should have while innately creating less of an environmental impact. Choosing to go tiny is the first step, and there are many intelligent choices that can follow.
Any tiny house design can be adapted to using high-performance building materials from Europe. Europe is miles ahead of the U.S. with the building materials and products they use, but also in their understanding of the reasons to build with such products. Steeped in ‘Passive House Design’ principles, The Healthy Tiny House Kit came out of a necessity to offer the tiny house community a collection of high-performance building materials that are typically difficult to source in the U.S.. The Kit is a way to build differently, with health and function paramount.
In order to build a proper tiny house, it begins with the trailer. A proper tiny house trailer allows at least 6″ of insulation to be imbedded into it allowing for maximum headspace inside the home as well as the minimum necessary amount of insulation under the house. The trailer is the foundation of the home so it must be designed to accurately support the weight of the walls and roof. It’s also helpful to have flanges for bolting the walls to the trailer, and a metal flashing underneath that creates a cavity for the sub floor’s insulation. These are necessary trailer components to jump-start building.
I’m a strong supporter of steel framing for many reasons. It saves weight by being 40%-60% lighter than wood while simultaneously being 25% stronger. I highly recommend Volstrukt, the leading steel framing company in the country. Their steel frames are engineered to work with your custom design while of course being structurally sound and able to sustain the intense vibrations that occur while driving down the highway. Their framing system is insanely easy to construct since they send each wall and roof portion panelized. The whole crew at Volstrukt is wonderful to work with and extremely helpful and eager to answer questions. Their tiny house starter kit pairs perfectly with The Healthy Tiny House Kit. I also love that they hardly create any waste in their shop. Someday when the tiny house will be taken down, whether that’s in 20 or 100 years, all of the studs are 100% recyclable!
Three major components of The Healthy Tiny House Kit are; the exterior Solitex house wrap, interior Intello house wrap, and all of the tapes that are used to seal the interior and exterior vapor barriers to the frame. These high-performance vapor membranes function better than any other products on the market and I think anyone will agree if they do a comparison test. I’m constantly driving by construction sites and buildings with various types of house wraps, ice and water shields, or window flashing tape that is peeling off the OSB and leaving gaping holes for water to penetrate. The Solitex, Tescon Vana Tape, and Intello are one-way vapor membranes, meaning that it allows moisture to escape the wall system when condensation occurs on the studs. These intelligent membranes won’t however allow moisture to enter the wall system due to a steamy shower or horizontal rain downpour. They keep the wall system independent from the exterior climate and the interior climate. You can check out these products here. They I have changed the whole way I look and think about building.
Photo cred: Living Big in a Tiny House
Next, the choice of insulation is hugely important and it doesn’t entirely boil down to R-Value (insulative rating for insulation). To work symbiotically with The Healthy Tiny House Kit, there are some key factors that the insulation must adhere to. It must be VOC-free. VOC stands for Volatile Organic Compounds aka chemicals, which off-gas. Spray foam in all varieties contains massive amounts of VOCs. During installation these VOCs off-gas into the atmosphere (poisoning the environment) and continue to off-gas for a specific period of time. If the spray foam isn’t mixed properly or if it doesn’t cure properly, which can be caused by a variety of non-ideal conditions, it will off-gas forever (poisoning the inhabitants). Unfortunately, this form of insulation is widely used and is currently the most popular form of tiny house insulation. This is due to its quick install, high R-Value, and some make the argument for rigidity or that it seals the house therefore not allowing air transfer throughout the wall system. But, we’ll go into that later…
As I stated earlier, all of the components in the The Healthy Tiny House Kit work together and with insulation like Havelock Wool Insulation that I highly recommend, mineral wool, or other natural fibers like hemp or even recycled blue jeans (cotton), the wall system is built to breath and to allow moisture to escape. This style of insulation, paired with an external and interior vapor barrier creates a wall system envelope that allows moisture to escape, due to namely condensation on the studs that can happen with wood or steel studs. This type of wall system functions efficiently on so many levels and doesn’t just boil down to the R-value of the insulation.
The gem of The Healthy Tiny House Kit are the ERV (Energy Recovery Ventilation) units. They are extremely efficient using .75amps of energy, equivalent to two laptop fans. Also, they have an energy recovery core that recovers over 90% of the temperature exiting the tiny house – whether it’s hot or cold – and replaces it with fresh air.
It’s my personal goal to have an ERV installed in every tiny house. It should be as important as the heating unit or kitchen sink. This is because one person in an average sized tiny house can consume the entirety of the air in just 8 hours. If you live with a partner or a dog that time is cut down considerably and then you start recycling each other’s exhale. Not only is this gross, but it’s not healthy for you or your house. The amount of moisture that one person produces combined with propane appliances, cooking, showering etc. creates high levels of moisture. No wonder tiny house dwellers are lifting their mattresses up to find the underside entirely covered in mold, constantly staving off mold growth along window sills, or ripping out the entire floor to save the rest of the home. Equally as bad are the stories of kitchen cabinets harboring mold growth until it’s too far gone to control. These are brutal ramifications of not installing a simple ERV into every tiny home. Check out various ERV Units here.
Finishing a tiny house with low or zero-VOC paints and stains is becoming easier now that people are more aware of off-gassing chemicals. Many people are finding that they have serious chemical sensitivities and can’t live healthily in conventionally built houses. I would love to see the tiny house community embrace a new style of building tiny homes that is healthy for it’s inhabitants and the environment.
To take it a step further, Mars Energy Corp. can build you a solar array to take your tiny home off the grid.