What do I use to mount a heavy framed mirror to a stud wall?

Question

I recently got my grubby hands on a beautiful, but extremely heavy, 4' x 7' framed wall mirror; it probably weighs around 100lbs, if not a little more.

I know what (exterior) wall to mount it on, exactly where the mount-points are, and have already installed two wood screws (2" long) into the studs. The mirror came with a pre-installed wire, and I'm hoping that these two screws would be stable enough to hold the mirror.

When we tried actually installing the mirror, we tipped it onto one screw, and tried to pivot the rest of the mirror onto the second screw. In the 10 or 15minutes that this process took, I observed the first screw start to tilt downward a little bit. Didn't want to take chances with such a heavy object, and stopped the entire process.

Here's my questions: 01. What specific hook or other fastener can I use to safely hang this mirror? 02. Will just two such fasteners suffice, or should I use more? 03. Should I remove the mirror's wire and use just the D-rings that it came with? 04. If I use #03 above, what method should I use, considering that there aren't any studs close to the D-ring mount points?

Thank you!

Answer 1

You'll probably have an easier time using a picture hanger than a screw, and it will leave your wall in better shape when you remove it. Picture hangers transfer the downward force into pressure into the wall because the nail is mounted at an angle. The screw, on the other hand, is being bent because you're acting as a lever, where the stud is the fulcrum, the drywall is just empty space, and the wire is the force applied at the end. Even if you get a stronger screw, you're still placing a significant twisting force into the stud.

You can't use your typical picture hanger for a task like this. The small hangers that come in most kits are rated to only 20-30 lbs. However, you can find hangers like this one that is rated to 100 lbs (and I'd still use two of them, since it will make adjusting for level much easier and reduce the risk of failure).

The other option is called a french cleat which are two interlocking rails, one that attaches to the wall, and the other to what you're hanging. As long as you install them both straight and level, you don't need to adjust the mirror for level, and it distributes the weight across a larger area, reducing the risk of a failure.

Answer 2

Not all fasteners are created equally. Drywall screws are tempered at a higher temperature, and are much more brittle than screws that are meant for structural purposes. If you picked up a box of 2" black drywall screws, you should not use them for much other than their intended purpose. A zinc-coated wood screw will bend before it breaks.. A stainless steel decking screw will definitely bend in this application...

I had to hang an extremely heavy antique mirror in a commercial setting once (an old hotel) and wanted to use the rings on the back of the mirror, rather than trust the wire. What I did was took a 2x4 and screwed it to the wall (at "d-ring" height) using a single GRK-Rugged Structural Screw through the horizontal 2x4, into the stud. I then screwed a cabinet screw (GRK makes one of those too..) into the 2x4 at each d-ring location and hung the mirror on the cabinet screws.

You don't need to buy GRK, I just love them cause I got a thing for fasteners, heh.. Any cabinet screw at a big box store or local mom and pop shop should do the trick. They are made to hang the "uppers" in your kitchen. Think of how much weight that is! All your plates and glassware of all sorts, hanging by usually just 4 screws per cabinet..

So:

1. Cabinet screws
2. Yes, two should be fine
3. I wouldn't use the wire (but make sure you're level, cause you only get one shot)
4. See above.

Good luck!