Light coloured building exteriors are a common thing.  Not only do designers use light coloured walls as a design statement or personal design trademark, but science and the law justify it. 

Basic science proves that when a thing is exposed to heat or light externally, its interior will be cooler if the exterior is a lighter colour as opposed to a darker colour.  The Building Code of Australia promotes this so heat load on a building does not increase the need for artificial cooling of a building interior.

So how can this be a design fault?

It is a design fault because light coloured exteriors don’t cancel heat (and glaring light), but only move it elsewhere.  The problem is not solved, it is shifted.

This shifted light and heat goes straight to the surfaces and atmosphere immediately outside of the light coloured thing, usually onto a neighbours property or building, or to the outside areas of the same property from where the reflected heat and light came from.  Maybe the children who live there are playing out in this excessive heat and light.

In my last house, a neighbor built a new house with white walls and a white steel roof.  The closest this new house was to the outside walls of my house was about 15 meters.  It must have been cool inside that house because I could feel the heat not only at my window but from the interior of my house.  I also felt I needed to wear sunglasses inside.  Does this pass as good design?

The base problem of reducing the need for artificial interior cooling is not solved at all.  The detrimental effect of the transferred heat is obvious, and the detrimental effect of the light is less obvious but nevertheless doubly bad for people who are caught in it because their eyes and skin are exposed to double the amount of suns rays that they would normally receive, and this can be a problem especially in Australia which has the most intense tissue damaging sunshine in the world.

Also, how does this heat and light transfer affect the earths atmosphere.  Before buildings were built, in vegetated parts of the world sunshine fell on mostly green and light brown coloured things, meaning less reflection of heat and light back into the atmosphere.  What have environmental scientists done to look into this atmospheric reflection?  And with the possible negative effects of reflection into the atmosphere, on a perhaps lesser note comes the negative effects it may have on the eyesight of our birdlife.

Surely modern materials will give us the insulation we need to colour our buildings in medium green, brown and other natural colours without resorting to light colours.  Certainly sandwich insulated roof and wall panels can do this with plenty to spare.  You could even go out into your yard and not have to wear sunglasses to protect you from the light reflecting off your own walls.

And imagine taking in a view of an urban landscape where buildings and vegetation coexist, and the buidings were coloured in medium natural colours.  It would look like you were out in the bush. How wonderful would that be?  Maybe a bit more thinking before following obvious dogma can reveal some exciting things that were missed in the rush to build.

Greg Blain is an Australian Architect, having started his career in 1978 as a first year architectural student in Brisbane, QLD. Greg registered as an Architect in 1989 and licensed as a commercial Builder in 2000.

Greg has concentrated his decades of experience to now focus on helping Architects and Designers achieve better results with documentation and other Practice matters, through his company ArchiAssist Pty Ltd.