The Daily Apple: Apple #671: Why are Barns Red?

Monday, May 5, 2014

Apple #671: Why are Barns Red?

I went on a trip last weekend, and I learned many things on that trip that I'd like to share with you. But I also have many pictures to go through and make them look better for public viewing. So while I get that stuff together, I'll tell you something I learned from another trip I took a week or two before.

So I was in the car with my parents, and we were taking a back-roads way to get somewhere. My dad said, "Look for the big red barn." That was his landmark at the corner where we were supposed to turn. I thought, why are barns red, anyway?

Thus a Daily Apple is born.

Even this dog is wondering, I wonder why that barn is red.
(Photo from Bedlam Farm)

When the States were first being colonized and Europeans were building barns here, they didn't paint them at all.

Present-day unpainted barn in Ontario.
(Photo from East Gwillimbury CameraGirl)

People back in Europe painted their barns, but paint was really expensive and the early settlers didn't have that kind of money. So they made do without paint.

The problem with the unpainted barn was that it was susceptible to mold and sun damage and other forms of decay. So you'd have to replace parts of the barn every so often, which could also get expensive.

After a few decades of trial and error, people discovered that one particular mixture was good at protecting the wood from some of the decay. Ingredients:

milk--a very common base in what was paint in those days
lime--the mineral, not the fruit, used as whitewash
linseed oil--a plant-based oil, good at repelling termites and other wood-eating bugs. It is naturally orange-ish tan and it stains wood that color too.

But while the linseed oil was good at stopping bugs, it wasn't very good at stopping the mold. Soon farmers discovered that mold really does not like rust. So they started adding rust to their barn-painting mixture. Rust, a.k.a. ferrous oxide or iron oxide, is also orange-ish in color, so that stained the wood an even darker color, something in between orange and dark red.

Irony note (hey, that's a pun!): back then, people were adding rust to the paint to keep the mold away. Today, people put paint on metal to keep the rust away.

(Read why physics guy Yonatan Zunger says we have dying stars to thank for red paint: short version; long version.)

Someone in Leelanau, Michigan has a sense of humor.

(Photo from Ohio Barns)

Then the Industrial Revolution happened, and toward the end of the 19th century, paint got a lot cheaper. The cheapest color of paint was red. Why? Because the ingredient that turns paint red is rust, and rust is some dirt-cheap and prevalent stuff. So the rust made the red paint cheap.

When people tell this story about the red barns, the don't say that the red paint also contained rust, though it probably did, at least at first. People say that farmers bought the red paint because it was cheap.

The result was, a whole lot of people started painting their barns red.* Eventually, barns eventually seemed to us non-farmers like they just plain ought to be red.

Red barn in Oklahoma
(Photo from Photos from [the Middle of] Oklahoma)

I can't find anything that says for certain whether red paint today contains rust. I suspect it does not. I suspect the red is made using some other even less expensive materials. Which in turn means that the red paint would not actually protect the wood from mold. So probably the wood is treated in some other method, and then painted red for cosmetic reasons.

*Not everybody painted their barns red. In some places, whitewash was still the cheapest coating, so a lot of barns in those areas were kept white. White is still the preferred color for dairy barns in some parts of the country, especially in Pennsylvania. But now that preference probably has less to do with cost and more to do with people's associations with white and milk and cleanliness.

Whitewash barn, location unknown
(Photo from donnan.com)

*In tobacco-growing states like Kentucky and North Carolina, barns are often painted black. This is because black absorbs and retains more heat, which helps to cure the tobacco that's stored in the barns.

Black barn with tobacco leaves hanging from the ceiling, being cured. This is in Harrison County, Kentucky.
(Photo from Prune Picker)

The red paint also makes a really nice contrast against green grass. So people like to paint red barns. I mean, they like to paint pictures of red barns. Like this: