Thursday, December 4, 2014

(Dec 4) Building shape determines efficiency of material use

I struggled with form over functionality for a long time and finally came to a conclusion that efficiency of design is crucial the smaller your building gets. the most efficient use of materials when building is a square. Look at most houses from the 40s. They are square with an entry directly into a room and all of the rooms flow from one to another. After coming out of the depression in the 30s, people had taken a hard look at the shape of houses and how to make the most out of limited resources.

We all remember these from our Grandparents or Great Grandparents. They were 800-1000 sf, rooms flowed around a central wall and there were rarely any halls. Every square inch was used and accounted for. The nook on L-Shaped houses today actually cuts off a lot of usable space for the materials used. If you flipped and inverted the L-Shaped wall, you could enclose the space that is cut off with the same amount of wall material. This leaves you the option of reducing the materials and labor to achieve the square footage that you want - OR - using the same amount of materials, you can achieve more usable space. Units are also more efficient if nested into multi-family housing.

Yes, I know. My wife likes the nooks from offsetting a room in a house. It adds style. Is an aesthetic thing that we've gotten used to seeing. We finally compromised when building our house and built a rectangle shaped building. I just wanted to point out that you lose efficiency of materials as you deviate from a square. More building materials and labor for less square footage.

In the above example, we have two boxes with a dimension of 5"x5". The difference between the two is that one has an area that's 25% smaller than the other. They both took the same materials to build, one just has less enclosed area. In a building, the L-Shape also takes longer to build in that you have 2 more corners to deal with and the roof on the L-Shape is also much more complicated. If you are truly trying to minimize your cost of building and maximize your available space, stay with a uniform wall length. 

The example I see all of the time is when I see the little entry nook cut out of mobile tiny houses. That little 3x3 area to stand in front of your door or to use as a tiny porch. I would much rather have a 3x3 closet inside or another 9 sf added to the living area than this little nook. Put an awning out front if you want shelter from the rain and who wants to sit in a little space by themselves. Move your chair out into the yard and enjoy the view! 

Yes, I agree that the L-Shaped houses are more interesting. They give you a little private area on both the inside and the outside. They just don't make good use of your materials and your labor. That said - when building a Tiny House, you are already dramatically reducing the footprint of a McMansion, so build it any way you want. Just my two cents worth! :)


  1. Circles and octagons provide more square footage, with the same exterior wall sizes as a square, but are not as functional by other measures

  2. Yes, I had contemplated listing them but felt they were outside of normal building practice, especially with so many of the Tiny Houses being build on trailers. Appreciate the input!