Why do houses have shingles and slanted roofs, but most other buildings have flat tops?
In: 8443
Because sloped roofs are cheaper, but only to a point, Because buildings with sloped roofs get stupidly tall the larger they get. For smaller buildings, sloped roofs and shingles is the most cost effective way to do it. But as the building gets bigger, the slopes go on for longer, meaning they get taller until it’s completely unpractical.
Think about a 4/12 pitch, which is rule of thumb about as shallow as you want to go for a sloped, shingled roof. A 100 foot wide building would result in a peak that’s about 17 feet taller than the wall height. That means the gable (the triangle peak part) will be taller than the walls it’s sitting on somewhere thereabouts. Which looks goofy and results in additional cost in siding and paint.
On a Walmart that’s 250 feet across, your peak height will be *83 feet* higher than your top of wall height. Think about the extra siding, extra paint, etc. You can pay for a lot of low slope roof for that.
At a certain point, under a certain length, sloped and shingled is cheapest. Above that length, the additional cost associated with a low slope membrane roof is less than the cost of siding and painting the gable, as well as how goofy it would look for the majority of the facade being gable. I’d argue that threshold is around 80 to 100 feet, which coincidentally is around where you see sloped roofs give way to low slope roofs.
Latest Answers