Let’s wrap our heads around corners, shall we! Would you like that? I knew that you would. (Thank you Mr. Rogers).
Corners keep turning up everywhere in the green building literature.
One more: sharp planning can limit costly corners.
Unless you plan on building a sphere, your new green building is going to have some corners. Building materials are notoriously linear so when these materials come together you might be dealing with a corner.
In fact, without corners there is no architecture. Without a corner or four you don’t have a building, you have a painting. Corners are the price we pay for dimensionality.
The Swiss-French architectural theorist and sometimes practitioner Le Corbusier wrote a poem espousing the virtues of the right angle. Corbu was all about some corners. Definitely a corner man, that Corbu.
Of course back in Corbu’s day no one was thinking too terribly much about energy efficiency.
Actually that’s not true: indigenous peoples and vernacular builders thought about it a lot. Perhaps we should have been studying them rather than Corbu who loved himself some corners a bit too much.
Disclosure: I went to a school where Corbu was worshiped. I had to bite my tongue as I never really dug his stuff all that much. The one huge exception is the chapel at Ronchamp which is a beautiful building and unlike anything else he designed. While Corbu was corner crazed he schooled us all on the power of western light with that little gem; definitely worth Googling, btw.
So here’s what we know about corners.
They are expensive to build.
They are hard to air-seal.
They catch the weather more than a plane.
They are slower to dry after the inevitable wetting.
They give a toehold to critters to build nest.
And how do we know these things? Mostly because Martin Hollady said it (so it has to be true).
So if we limit the number of corners we begin to hedge the design towards a direction that building science suggest is more better.
This is not suggesting banal or boring boxes by the way. Limiting corners can be viewed as a challenge to carefully detail the intersections and lavish attention on the materials. So if Corbu overdid the corners his contemporary Ludwig Mies Van Der Rohe had it right when he said “Less is More”.
I find that trying to limit a small house to 6 corners forces a discipline on the design that doesn’t otherwise operate. More often than not we end up with 8 corners but that’s not too bad. A big house might find the need for 12 to 16 corners but if you discover your design has over 20 or 30 corners you might consider editing that number (unless your name is Vanderbilt……………………..they Built-More!).
Avoiding corners applies doubly to the roof. If you must have a dormer go ahead but realize that that dormer is going to cost you in terms of first cost, maintenance, and operations. It’s also putting the framing crew at increased risk by requiring them to be on the roof longer than would otherwise be necessary.
You may have noticed that roof valleys (a special sort of corner) tend to be the last part of a shingle roof to dry out and the place most likely to catch leaves and twigs. Valleys are also very expensive to frame and pose a unique structural challenge (much harder than a hip, for example).
Think about it; any fold in the roof plane is a big deal from an air-sealing perspective. Thermal energy rises so it’s going to task the ceiling-roof assembly more than any other portion of the building envelope.
Something I picked from studying the Passive House movement (I am not a disciple of the Passive House movement, by the way: too dogmatic and limiting for me) is to think carefully about any penetration through the building envelope. If we can combine bathroom vents that will help. If we can limit plumbing vent stacks that will help.
If you’ve seen those thermal images of buildings you’ve no doubt noticed that the heat is always escaping at the corners.
Lest you think I came by this thinking easily let me dissuade you. As a freshly minted architect back in the 90’s with a commission or three I found myself overly deploying those precious corners. Looking back I think it was an attempt to prove I had mastered this incredibly complex media (I hadn’t. I still haven’t but I have managed to become aware of the vastness of the challenge; I’ve come to appreciate that that is actually quiet an accomplishment).
If you’re going to use a corner make it count. These things are too valuable to go tossing around willy-nilly.
Final Pending Pun Warning (FPPW).
Cutting corners is good for you (when it comes to green building).