I live in a newly built apartment building and was planning to mount a TV on the wall. As usual, the walls are drywall, so I was planning to use molly bolts. The first hole was easy to drill, but the second hole hit something hard inside the drywall. I discovered I had hit metal. I checked the plans to ensure it wasn't a water pipe or anything else, and according to the plans, there shouldn't be anything in the wall, which is not load-bearing.
I thought it might just be a metal stud and tried to drill through it, but now I'm having doubts because it's very difficult to drill through. I've probably been drilling for 15 minutes and have only penetrated about 3 mm into the metal with a metal drill bit. According to my stud finder (a cheap one from Clas Ohlson), the metal object is about 40 cm wide, so it's not a stud. The metal object is also very stable, not wobbling at all, which I would expect a stud to do.
Does anyone know what I've encountered and how to successfully mount a TV with this in the wall?
I thought it might just be a metal stud and tried to drill through it, but now I'm having doubts because it's very difficult to drill through. I've probably been drilling for 15 minutes and have only penetrated about 3 mm into the metal with a metal drill bit. According to my stud finder (a cheap one from Clas Ohlson), the metal object is about 40 cm wide, so it's not a stud. The metal object is also very stable, not wobbling at all, which I would expect a stud to do.
Does anyone know what I've encountered and how to successfully mount a TV with this in the wall?
Is the house built of metal? I mean the load-bearing structure made of metal beams covered with plasterboard.
Then it could be such a beam.
Drilling 3 mm over such a long time... Buy a proper drill! I usually go through 5 mm plate with an 8 mm drill in less than 30 seconds. With the screwdriver!
Then it could be such a beam.
Drilling 3 mm over such a long time... Buy a proper drill! I usually go through 5 mm plate with an 8 mm drill in less than 30 seconds. With the screwdriver!
Thank you very much for your answers. It might very well be some type of metal beam as you mention, the whole wall which is about 2 meters is very rigid. However, it is supposedly not a load-bearing wall and according to the drawing, there should not be anything in the wall, but beams might not be included in drawings. Now let's say it is a metal beam, how do you attach something to such, how thick do you think the beam is, etc. It's hardly suitable for a molly plug like in the other hole, I don't think my drill can manage to drill 10mm in such hard metal beam, but with a more high-quality metal drill bit it should work with, for example, 4mm? The metal drill bit I have now is from a package from Clas Olsson, 6 wood drill bits, 6 concrete drill bits, and 6 metal drill bits - I guess you get what you pay for 
Small update: I've now gotten through the metal, which was about 1 cm thick. Now comes a follow-up question: I started drilling with a 10mm bit through the drywall, then switched to a 3mm bit when I reached the metal. I'm thinking of maybe patching up and then drilling a new hole with a 3mm bit through both the drywall and the metal, and then using a screw that's suitable for metal to go through both. Should be able to hold a TV weighing just under 20 kg, right? Do I need to use a plug? If yes, then I'll probably need to drill a larger hole in the metal.
Drill up to 5mm. Then thread up with a tap M6.
It will sit like a rock when you tighten with a stainless steel screw M6. You don't need to drill anywhere else. The screw will center itself in the 10 mm hole when you tighten it without the TV.
It will sit like a rock when you tighten with a stainless steel screw M6. You don't need to drill anywhere else. The screw will center itself in the 10 mm hole when you tighten it without the TV.
Why use a stainless screw??? The installation is supposed to be indoors. Moreover, it's much easier to break a stainless screw compared to a "regular" zinc-plated screw of 8.8 quality.kamilenski said:
Otherwise, I agree that threading the hole and using a screw is a perfectly fine solution. It will hold much better than a new hole for a "molly".
Even better, but more advanced, is to use a bolt in 12.9 quality. You won't break that easily. But as mentioned, one in 8.8 should suffice since it's probably not a 60-inch CRT you're mounting...
I'm a bit curious about how to find a 10mm beam in a non-load-bearing wall. It's not a small beam, would have looked up a bit more about why this exists in the wall, or maybe not now that it's drilled into.