Tiny House Building Science

** NOTICE **
At least one aspect of the following post differs from that which we implemented
in the end-design and/or the actual construction of our Tiny House.
For the most accurate and up-to-date information please refer to our eBook.

Along with the cold temperatures of winter and the accompanying snow comes what appears to be total cessation of work on our tiny house.  Not so!  While the physical work may have entered a short hibernation period, the planning and sourcing stages have proceeded ‘full ahead’.

Perhaps the largest single issue in the design of our tiny home has centered on how to construct the building’s envelope.  “Envelope” is just a fancy word that describes the shell; the floor, walls and roof that, together, form the parts one sees when looking at the outside of a structure.

This is the 1st of 4 posts detailing our own “crash-course” on building science and how we, ultimately, decided to build our tiny home’s envelope.


What is Building Science?

The concept of what constitutes an “envelope” grew somewhat complex as I began to apply my very general knowledge of building science “rules” to such a tiny dwelling.  Building science, a term you don’t necessarily hear tossed around much, if at all, when it comes to tiny houses (nor amongst the large house crowd for that matter, although this is changing) is a relatively new concentration in the science & construction fields.  It’s interdisciplinary focus delves into the many factors that affect buildings, with an eye to understanding the many forces at work and coming up with solutions and techniques to minimize the negative effects of these forces on all aspects of a building’s performance.  It is really neat stuff, some of which appears to finally be gaining traction within the construction community.  I don’t think the same can be said for the tiny house sector, at least as it pertains to what I’ve been able to find online.

Building Science and the Tiny House Movement

Even a cursory search of the internet rapidly showcases the diverse methods, many questionable from a building science perspective, which people continue to utilize in the construction of their tiny homes.  In many cases, folks appear to treat their diminutive dwellings as large Styrofoam coolers (the kind of thing you put food in to keep it cold), stuffing walls, floors and roofs with layers upon layers of unforgiving rigid foam insulation and then fastening it all in place using spray foam on all four edges.  Others, perhaps unsure of what insulation approach is best, end up wildly underestimating the amount of insulation needed, only to later suffer uncomfortably cold floors or the indignity of having to supplement their proudly displayed heating system just to keep the place habitable as the mercury drops.  Still others attempt to implement the latest in insulation strategies by paying folks to come in and fill each and every stud, joist and rafter cavity full of polyurethane foam.  Some may even omit exterior plywood sheathing altogether in favor of foil-faced polyisocyanurate panels, the so-called “warm wall” method of moisture management which, in the case of a house built on a trailer, appears to willfully disregard the shear and racking forces at play while being towed down the highway at 65mph.

If I appear at all cynical at the dubious methods some have chosen to protect their buildings from the direct effects of Mother Nature and the side-effects of human habitation, this is because I am.  But my cynicism is not rooted in a “told you so” mentality or something equally as rude, but in a real concern for a whole generation of well-intentioned and highly sustainable structures that may very well fail before their time, some potentially adversely affecting the health of their inhabitants in the process.

We Need to Learn More about Building Science 

I will direct all those interested in learning more about preferred methods and best practices as it relates to the science of home construction to the website of the Building Science Corporation, with which I have no personal or business relationship.  In fact, I can’t even get them to return my emails.  Anyone building anything that people will live in can benefit from  the wealth of knowledge that exists there in the form of “white papers” produced by this for-profit company, most, if not all, of which are provided free of charge.

I am no Building Science expert, though I know enough to realize that many of the online purveyors and supporters of the tiny house movement require a rapid influx of education in this department to ensure that the legions of DIY’ers out there are better equipped to make intelligent decisions when it comes to choosing any given insulation and moisture management strategy.  Tiny houses are quite unique in this respect and people need to understand what they’re getting into when it comes to the heightened threats of poor indoor air quality, mold, and how to prevent something as simple as tannins present in cedar siding destroying the waterproof/breathable qualities of modern building wraps, before they commence building their tiny dream home.


This is Part 1 of a series of posts in which we examine building science as it pertains to our tiny house.  Our next post in this series will examine the methods we have chosen (after much research, consultation and contemplation) to protect our home from the elements and shield it from the negative results of human habitation.


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