What's behind my drywall?

Question

I live in an apartment in NYC, built in 1973. I'm trying to mount something to the wall which requires two screws placed 5 inches apart vertically.

I used a stud finder to find a vertical stud in the wall (3 inches across), but when I drilled it went in an inch before encountering a hard surface. Definitely not wood. I applied pressure and drilled, and it finally "broke through" in a matter of seconds, and it felt like there was nothing behind that.

I tried screwing in a screw, and it gets to the 1 inch point before making a metallic grinding noise -- I'm assuming what I drilled through was some sort of metal plate. The screw definitely "threads" (if screwed in, it cannot be screwed out), but it's very loose and unable to be tightened.

So, what is this vertical thing behind my drywall? How can I mount things to it?

Answer 1

Because it only takes a few seconds to drill through, is only about three inches wide, and runs vertically, It sounds like it's a metal stud (as you've found out). Metal studs are not as strong as wood studs when hanging stuff, but the one meal stud, along with the strength of the drywall should be enough to carry 20+ pounds. If it were approaching 40+ pounds, it would be better to span two metal studs.

I've had the best experience hanging items on metal studs with toggle bolts. Get the two smallest toggle bolts you can find that are: 1. Rated for at least 40 pounds each, 2. Long enough to go through the drywall and studs. Depending on how big the mounting holes for bicycle rack are, you may need to pick up some washers too. You want to put the toggle bolt through the drywall and stud. Find the center of your metal stud and drill a 1/8 inch hole at the height where your mount is going. Then, make the hole progressively larger until the toggle fits through. Then, just follow the instructions that came with the bolts as if you were putting them just through drywall.

Answer 2

but when I drilled it went in an inch before encountering a hard surface. Definitely not wood. I applied pressure and drilled, and it finally "broke through" in a matter of seconds

This could be bad depending on what you actually drilled through. It might be a good idea to open up the hole enough to see what is there, but do it without drilling and do it carefully.

Why could this be bad? If it was a metal plate installed to protect electrical wires, a wire itself, or if you drilled into a pipe*. You probably can't be sure until you take a look.

I would carefully try to cut a larger hole through the drywall. If you can cut a clean square around the area it will make it easy to fix, as you can cut a square of drywall and use it as a patch for the area you removed. You can possibly replace the square you removed.

You should do this using a drywall knife, or another sharp knife that allows you to make clean and controlled cuts.

If you're not that handy, it might be better to leave it as is, as you don't want to hurt yourself or do more damage.

Once you know what's there, then it's easier to suggest what to do next.

Answer 3

Use wood to reinforce and strengthen. Metal studs are just thin sheet metal that has added strength only by their shape. Even anchors and toggle bolts can easily rip out of them easily or over time. Many hardware stores will sell decorative beveled hardwood that could easily be screwed using several (or many, depending on the needs) screws along a suitable length of the stud, which would hold the wood securely in place, so that mounting your bike hanger can be more secure with it's own mounting options.

If it requires two holes, 5 inches apart along the same stud, then I would recommend something like a 1/2" - 3/4" thick wood "plaque" about 10"-12" tall, using about four anchor bolts evenly spaced down the middle, or optionally, a flat, asymmetrical length of quality (1/2" or thicker) hardwood molding the full height of the wall (floor to ceiling), which could allow for using common metal-stud "drywall screws" to strengthen and secure to the stud at about every 4". Then mount your bike holder to the center of that, making sure the screws or bolts are completely through both the molding and the stud.