The wonder of modern drywall

Minecraft isn’t real life; You cannot stack dirt blocks to an unlimited height. This is a shame, because dirt has great value as a construction material. It is in abundance. You can go out right now and put a handful of dirt in your pocket without anyone stopping you. Just like Minecraft.

To turn dirt into a reliable building material, you need another Minecraft staple: wood. If you take a bunch of sticks, weave them into a tapestry, then sprinkle on wet dirt (also known by its technical name clay) and let it dry, you get wattle-n-dub, a method of building walls that has been a mainstay for at least 6,000 years, long before mud bricks. Some buildings still standing today contain wattle-and-daub panels from 700 years ago.

If you fast forward the reel of history, it is remarkable how consistent certain activities have been throughout each era. The time-tested technique of applying moldable paste to a rigid canvas has hardly passed through the ages as a method of building walls. Even before the Industrial Revolution, the cutting edge technology at the end of the 20th century was plaster-n-lath. Instead of random sticks, you use uniform wooden strips. Instead of dirt, you use plaster made from gypsum, a mineral known for its fire resistance. Same, but different.

The problem with layering paste to build walls is that it is a skilled trade and incredibly labor-intensive. The plaster wall was constructed in-situ on top of the lath canvas, and required several layers, each with its own drying time. You rub, then wait for it to dry, then rub again, then wait for it to dry. It would take a skilled plasterer a week or two to build the walls of a typical house. The end result was either decent, or a jumbled mess. You are fighting against gravity, after all.

As someone who has spent a great deal of time grappling with the quirks of a house built in 1901, I can personally vouch for the joys and sorrows of old plaster and wood walls. It is also impossible to fix light objects such as picture frames on the wall, as even the smallest holes from nails or the like will break off and turn to dust. Victorian era homes relied on picture rail molding near the ceiling, with hooks for installing anything important. You can’t pick a random spot to photograph your cat; You have to hang everything on a string, and if you’re hanging on one string you might as well hang them all.

The plaster mix then used was a home mix, with recipes matching the needs of the climate and the availability of local materials. The popular additive was asbestos. While today we all know about its acute toxicity, the reason asbestos was so widespread from the 1870s to the 1970s was that it was exceptionally fire resistant. It was better to die from a lung disease you didn’t even know about than to die in a house fire you definitely knew about.

Which leads us to modern drywall sheets. Drywall, also known as gypsum board or plasterboard, is basically a rigid panel made by pressing a thick layer of the familiar gypsum plaster between two durable sheets of heavy paper. This creates a strong, smooth and easily paintable surface that forms the backbone of most modern interior walls and ceilings. Developed in the early 20th century, it was not until the 1950s that drywall rapidly took over as the standard for walls and ceilings in American homes.

Superficially, drywall looks similar to plaster and lath wall and is made of the same materials. While both are a hardened layer of gypsum powder, drywall sheets are manufactured off-site on a large scale in large factories under tightly controlled conditions for consistency and efficiency, then shipped to construction sites ready for installation. Instead of a plasterer laboriously ensuring straightness on a 12-foot-long canvas of paste, the gypsum powder is extruded into uniform shapes, sandwiched by protective layers of heavy-duty paper like an inedible ice cream sandwich. Cheap, uniform and free from defects.

The final product is simultaneously stronger and more flexible. Because drywall is a dense and uniform mixture, hanging anything on the wall (from pictures to shelves, TVs, or even heavy items like cabinets) is a modest exercise, using either a simple nail for a small frame, plaster anchors for medium loads, or toggle bolts for the real heavy hitters.

Picture rails are a weird and twee feature that few people today know what their purpose is, but anyone who tells you they’re just as good for hanging things is committing perjury. Speaking from experience, I’ve spent a good part of my life grappling with the horrors of old-fashioned plaster wall hangings. Something as simple as setting up a coat rack turned into a month-long effort. Ideally you bolt it to load bearing wooden studs, but plaster and lath defeats normal efforts to identify where the studs are. Density scanners that distinguish ‘blank’ gaps between studs are confused by the presence of wood laths. Magnets that identify studs by the presence of metal nails are similarly thwarted by thick plaster layers. In fact, the only practical option is to drill several pilot holes until you hit something solid.

Even modern glue-based options can’t match the untested plaster mixes of old. Paint does not wear off like today’s paper coats, and sticker mounts will fall off old walls and pull a large portion of the paint down with them.

It all adds up. With the exception of lath lattices, buildings now have more space in wall cavities for better insulation and drainage.

Drywall’s fatal vulnerability has long been water damage. Luckily, the quiet innovation engine is still humming, producing mold-resistant, fire-resistant, and soundproof drywall. There are even ‘smart drywall’ systems with integrated temperature, humidity and sound sensors. If you’re willing to connect your wall to WiFi then you’re in luck.

Yes, it’s all boring. No sane person should ever get excited about a blank wall, let alone read thousands of words on the subject. But the walls of your home are a frequent reminder that most real architectural and design advances are almost entirely invisible.