What's Behind Your Chicago Wall? Drywall, Plaster, Brick, Concrete and Metal Studs Before You Mount a TV

You have the TV, the spot and maybe the mount. Then you hold the bracket against the wall and realize you have no idea what is behind the paint. In Chicago that is a fair question: one block can hold a brick two-flat from the 1910s, a vintage building with plaster on wood lath and a newer condo framed in metal studs.

The short answer: the wall decides the hardware. Plaster or drywall is the first thing to settle, and a pushpin and a light switch cover usually settle it in a minute. Then find what the TV actually hangs from: a wood stud, a metal stud, brick or concrete. Here is how to tell, wall by wall.

Is my wall plaster or drywall?

Press a pushpin into a spot the TV will cover. If it slides in easily, it is drywall. If it resists or the surface splinters, it is plaster. To be sure, look at the cut edge behind a switch cover: paper on both sides of a white core is drywall, thick layers with no paper over wood lath is plaster.

How to tell what wall you have: five quick tests

1. Try a pushpin

Press a pin into a spot the TV will hide. Drywall takes it easily. Plaster resists, and an old wall may splinter around the point.

2. Feel the wall

Put your palm flat on the wall, then on a wall you know is drywall, like a newer closet. Plaster feels harder and cooler to the touch.

3. Look behind a switch cover

Unscrew the cover plate from a light switch and look at the edge of the wall around the box. Paper on both faces of a white gypsum core is drywall. Thick layers with no paper, with wood strips behind them, are plaster on lath.

4. Run a magnet along the wall

Slide a strong magnet slowly across drywall at the height of the mount. It sticks to the screws that hold the sheets to the studs, and a vertical line of screws is a stud. Studs are usually 16 inches apart and rarely more than 24.

5. Check the year the building went up

Built before the 1940s, expect plaster. Built after the 1960s, expect drywall. In between, it could be either, so the tests above decide.

Each wall type and what holds the TV

Drywall on wood studs

This is most suburban houses and most interiors built since the 1960s. The drywall itself holds almost nothing, so the mount goes into the wood studs behind it. Studs usually sit 16 inches apart on center, sometimes 24.

The catch is placement. Studs rarely land where the TV looks best, and they can bow up to an inch as a house settles. A wall plate wider than the stud spacing lets you center the TV and still hit wood. Choosing the right mount covers which type suits the room.

Drywall on metal studs (condos and newer buildings)

Many Chicago condos and newer buildings are framed in metal studs. From the room they look like any drywall, and a stud finder still finds them. The magnet test gives them away: a magnet clings along the whole stud, not only at the screws.

Metal studs take different hardware. Mounts made for them ship with heavy-duty toggle bolts that lock behind the stud, and one such full-motion mount is rated for TVs up to 100 lb on studs up to 16 inches apart. We install on metal studs with hardware rated for them, so mention it when you text us the room.

Lath and plaster (vintage Chicago homes)

Before drywall, interior walls were plaster troweled over thin strips of wood called lath. It is hard, heavy and brittle, and old Chicago plaster hides studs well. Stud finders often give false readings, and a pushpin will not go in.

Drill blind and you get a cracked wall, or a bolt in a strip of lath that was never meant to carry a TV. The order that works is to find the stud, confirm it with a small test hole the mount will cover, then use hardware suited to plaster. Our TV mounting service checks the wall before anything is drilled.

Brick and plaster over brick

Chicago's bungalows and the brick two-flats of the 1910s and 1920s were built with brick walls on concrete foundations. In an old brick building, an outside wall may be brick right behind the plaster. One 1890s Chicago two-flat has plaster and lath on furring strips about 2 inches off a wall two bricks deep.

Exposed brick and brick behind plaster are the same job: masonry anchors in the brick itself. Mounting a TV on brick walks through it step by step. Mortar is much softer than brick and an anchor's grip in it weakens over time, and a hole within half an inch of a brick's edge can crack it. Behind plaster, the anchor has to reach the brick, not stop in the gap.

A brick fireplace adds heat and height to the list. Mounting a TV above a fireplace covers both.

Poured concrete (high-rises)

If the pushpin will not go in and you live in a concrete tower, you may be looking at a concrete wall or column, sometimes with drywall over it. Concrete holds a TV well with anchors made for it. It is also the one wall where the building gets a say before you do.

Some towers are built with post-tensioned slabs, with steel cables under load inside the concrete. A condominium guide on post-tensioning says no one should drill or core that concrete without knowing exactly where the cables run, and it recommends that boards require an x-ray or radar scan before significant drilling. Ask management for its rules first, and tell us about them when you schedule.

Tile, shiplap and paneling over the wall

A finish is not a wall. Tile, shiplap and wood paneling sit on top of drywall, plaster or masonry, and the TV hangs from whatever is underneath. Run the same tests at a switch cover to find out what that is.

Chicago building types and the walls inside them

Bungalows and brick two-flats. Brick outside walls on concrete foundations, most of them from the 1910s and 1920s. Inside, expect plaster on lath unless the house has been redone in drywall.

Greystones, courtyard buildings and older two-flats. Older buildings often have plaster or brick walls, so check the wall before drilling and use hardware suited to it.

Condos and newer apartment buildings. Drywall, often on metal studs, and in high-rises concrete walls and columns with building rules on top.

Suburban houses from the 1960s on. Drywall on wood studs, the easiest wall on this list.

A rehabbed vintage unit can be any of these, which is why the tests beat the year on the deed. Hiding the cables depends on the wall too: see how to hide TV wires.

Common questions

How do I know if my wall is plaster or drywall?

Press a pushpin into a hidden spot. Drywall takes it easily, plaster resists. Behind a switch cover, drywall shows paper on both sides of a white core, plaster shows thick layers over wood lath with no paper. A home built before the 1940s is most likely plaster.

How far apart are studs in old houses?

Usually 16 inches on center and rarely more than 24, but spacing varies with the age of the house, and studs can bow up to an inch as it settles. In plaster, confirm a stud with a small test hole the mount will cover before you rely on it.

Can you find studs in plaster and lath walls?

Yes, with patience. Stud finders often give false readings, so treat one as a first guess. Confirm the stud with a small test hole in a spot the mount will hide, and only then drill for the bolts.

Can any wall hold a TV?

Almost any wall can, if the mount goes into the right thing behind it: wood studs, metal studs with toggles rated for them, brick or concrete. Drywall alone is not enough. If the spot you want is not a good fit, we suggest a better one.