That’s the last thing I want to hear from a code official or investigator – after the project begins. So, we’re going to do this the right way. Plan, plan, plan. In order to plan, we must first do a significant amount of research. I do know one thing, (OK, I know a few things, however this one thing is pertinent): Permanent structures require a foundation, which I will not have. So what do we call a shipping container home that rides/rests on wheels then? A travel trailer, like an Airstream? A mobile home? A modular house? Recreational Vehicle (RV)? I must admit, this part gives me a headache. We’ll walk through a few concerns.
For those who have built a tiny house on wheels before me, the question comes up early in the process – What is the legal designation of the home? This greatly affects the permitting process, where it can be ‘parked’, the ability or even necessity to move frequently, ability to travel on the open road, and with what codes it must comply. Certain designations don’t allow full-time living. I must, therefore, determine what it most important to me. What do I want to achieve with this project?
This Will Take a Lot of Energy
The research, that is. The home will use so little, it may as well be considered a shed. Oh, right. Sorry, it’s too big to be a shed in the city of Seattle, as 11 m² (120 sf) is the max size for an un-permitted shed. Let’s talk about the codes for a moment. Building codes are written with very specific concerns – health, safety and welfare, and most states have adopted the 2012 International Energy Conservation Code (IECC) to address the growing concerns around energy use. As a building, if that were the route to take, the project would have to meet very stringent regulations, especially regarding energy efficiency of systems and insulation values. It’s still unclear to me whether this is applicable in this situation, however let’s imagine what would happen if more people started building smaller to save on both first costs and energy.
From the ‘Department of Common Sense’: it should not be surprising that a very small structure has less volume of air to heat and cool than it’s more traditional counterpart, so will no doubt use less energy. However, most energy codes are written with a one-size-fits-many approach. Several tiny homes on wheels have proven energy bills – when they’re not off-grid – which typically use about $25-40 per month for all energy costs. So, even for permanent structures, it would simply make sense to build smaller to save money. Many local jurisdictions have minimum sizes for structures which prohibit very small homes, which can artificially drive up the amount of cost for the home. It can take many years of lobbying, however laws and local codes are meant to be altered as society changes.
To illustrate how size does matter, a report by EarthAdvantage that confirms the above assumptions. The report, very lengthily titled “A Life Cycle Approach to Prioritizing Methods of Preventing Waste from the Residential Construction Sector in the State of Oregon”, helps identify the following critical facts:
- Of all the 30 identified methods of reducing waste or reusing materials in residential construction, reducing the size of a home is the most significant factor in reducing it’s overall energy consumption.
- Reducing home size by 50 percent results in a projected 36 percent reduction in lifecycle greenhouse gas emissions.
- Over 80 percent of greenhouse gas emissions over a home’s 70-year life occur during occupancy and are attributed to electricity and fuel consumption.
Due to this report’s findings the Oregon Reach Code, an optional green building code, the state of Oregon is now beginning to consider size as an important factor when determining the sustainability of a home. Not that this information helps me directly in Washington State, as I plan to stay here for now.
And More Research
I plan to have a consultation with one of the local tiny house builders, familiar with my region. This should arm me well with the information necessary to navigate the legal waters of not just how to permit the project, it will also ensure I don’t under or over-insulate – as every millimeter of floor space counts. It’s important to nail down these details before completing a design, as 2590mm (8′-6″) is the maximum width of my project to be able to travel any U.S. road without a “wide-load” permit. It might be interesting if the insulation could be on the exterior, freeing up more space on the interior.
There are also several seminars around North America that broadly cover how-to topics around the logistics, concepts and hands-on.
Another good resource is this e-book “Cracking The Code: a guide to building codes & zoning for tiny houses”
If everything works out as planned, I may be attending the Tiny House Conference in North Carolina this April.