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I have a flat screen TV that I have always mounted on drywall using plastic drywall anchors—eight of those has always held it up just fine and I probably could have used just four.

New home is in a 1940 building (New York City), and the wall is not drywall, it’s a wooden board with plaster over it. My searching on the subject suggested that lath & plaster is likely for the time and place, only the wooden board doesn’t look like lath from the photos I have found.

Here is what the interior of the wall looks like, as seen in the cut-out for various cables relevant to the TV:

a hole in my wall showing cross section of the wall

(Yes, I also wish they had used proper jacks for those wires; the bedroom side of this wall is worse and I’m not yet sure what I want to do about that.)

I can’t get a good photo of the far side of the wall space, but it’s the same kind of board, as far as I can see (which isn’t very but maybe a foot or so) in all directions. It’s not thin strips like I usually see described for lath.

So what is the appropriate hardware to buy for this kind of wall, that will hold the TV securely to the wall? There are some holes in the wall already, looks like they drilled four holes and inserted sort-of-similar plastic pieces past the plaster and into the wood, but I’m not sure exactly what they are (they’re in pretty deep and I can’t see them very well) and what the process is.

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  • Side issue: How did that cable get scorched??
    – DJohnM
    Jan 16, 2021 at 2:34
  • @DJohnM Are you referring to the white? I had assumed that was white paint (the wall was painted white when we got here) and/or plaster. Anyway, the co-ax cables were literally just shoved into the wall space, and I have no idea if they’re connected to anything. The bundle of blue ethernet cables seen on the bottom were the ones that actually came out of the wall. They’re zip-tied to an HDMI cable that isn’t plugged into anything.
    – KRyan
    Jan 16, 2021 at 13:37
  • Oh... I saw a white co-ax cable with black, slightly blistered sections...
    – DJohnM
    Jan 16, 2021 at 16:31

2 Answers 2

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The wood that's visible around the edge of that opening is plywood. I would suggest opening up several other boxes throughout the apartment (or at least along that wall) to see if they're all like that.

If this wall seems to have a consistent plywood backing, you're in luck because all it takes is a few of the appropriate sized lag bolts (specified in the instructions of your wall mount) and you're good to go. You can hang that thing anywhere you want - plywood has a lot of strength and can take the weight of just about any TV/mount combo out there. So much so that the frequent recommendation is to attach plywood to the studs then attach the mount to the plywood. You just get to skip the first step.

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  • Excellent, thank you. I’ll check those instructions for the size. Unfortunately, this is the only box on that wall (well aside from the one immediately next to it visible in the photo), but looking around inside does seem to have plywood as far as it goes.
    – KRyan
    Jan 15, 2021 at 18:28
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    To be certain that the area where you're hanging the mount is plywood, I'd suggest drilling small holes as pilot holes for the lag bolts, @KRyan. Make sure that the drill bit is extracting wood when you get all the way through, not just plaster. To be 100% certain, you could cut a hole (about the size of the one in your picture) in an area that will be covered by the TV mount, just to be sure you've got more plywood there. You won't have to worry about patching it until you take the TV down. ;)
    – FreeMan
    Jan 15, 2021 at 18:31
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    Well, luckily, the plan is to put the TV over the hole you see in the photo, so I think pilot holes will cover me. Thanks so much.
    – KRyan
    Jan 15, 2021 at 18:46
  • I can’t find the documentation for the mount, but I know what size screws have always held it up before, and I know the size of the slot for screws from the mount itself. Is there any reason that buying lag bolts at least as thick as the screws I’ve used with drywall anchors, but not too thick to fit in the slot, and at least as long as the wall is thick and with at least as much “lag” as the plaster (but not so much it’s beyond the wood) would cause a problem?
    – KRyan
    Jan 15, 2021 at 20:10
  • A little beyond the wood in plywood is perfectly fine.
    – manassehkatz-Moving 2 Codidact
    Jan 15, 2021 at 21:26
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I believe most TV wall mounts are designed so the span at least (2) wall studs. So unless your adamant about the location on the wall all you need to do is locate (2) adjoining studs. Do this with a stud sensor and/or tape measure.

Once they are located set the mount at the height you prefer, mark the holes, drill, lag bolt and hang TV.

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  • Research online suggested a stud finder would not work with lath and plaster. This is plywood (apparently) and plaster so it might be different, but I don’t have a stud finder to check. Would a stud finder work? Don’t want to buy one of it will be useless.
    – KRyan
    Jan 15, 2021 at 22:14
  • I don't believe your entire wall has plywood under the plaster. That's not how plaster is commonly installed. It's usually strips of wood, but either way there's wood below. Stud finders work by ultra sound and/or by magnetic sensors. It will work by sensing the nails that attach the lath to the studs (or whatever is under your plaster). If you'd rather not invest in a tool you can easily find a stud and than know they are spaced 16 inches on center.
    – ojait
    Jan 15, 2021 at 22:50
  • You will want to secure the mount to studs not anywhere on the wall. The instructions make this same statement. Mount it with lag bolts and into studs. Not anywhere on the wall.
    – ojait
    Jan 15, 2021 at 22:55
  • Yes, I believe the instructions did make that recommendation, but I’ve also mounted this TV on plain drywall several times, with no stud. It’s really not that heavy. That said, there are existing holes where the previous owners put their mount—and they are 16” apart. So I suspect those are the studs anyway. I’ll just put my holes vertically in line with theirs; want to cover them anyway...
    – KRyan
    Jan 16, 2021 at 0:57
  • @ojait this is a 1940s building in new york. You cannot assume studs 16" apart.
    – De Novo
    Jan 10, 2022 at 5:17

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