Hanging HEAVY stuff from my old plaster ceiling

December 14, 2013 3:07 PM

I'm hoping to hang a heavy sliding door system from the old lath and plaster ceiling. Are bolts screwed straight up into the wood going to be enough support--or will they just pull out? All the information I can find on sliding, barn door style systems show the rail support being screwed into a wall. But I was able to buy some ceiling brackets, so that must be "another" way. I can't bolt from above, so: am I asking for trouble screwing straight up into the wood, and expecting the bolts to support a 10-foot track and two 4x8 doors?
posted by largecorp to Home & Garden (17 answers total)

I think you'll need to locate the ceiling joists. If you're talking about screwing bolts into the laths, that's a bad idea for anything heavier than a light fitting.
posted by pipeski at 3:11 PM on December 14, 2013 [3 favorites]

You need to find the joists/studs. They are probably about two feet apart. A decent stud finder will work on lath and plaster, or you can just use a drill to explore. The lath and plaster is not going to be strong enough to hold this, especially from the ceiling. It MIGHT work if you used toggle bolts and really spread the load out, but I would not risk it.
posted by rockindata at 3:12 PM on December 14, 2013

Agree. You need to find the joists. And also, you don't screw into anything with bolts. Bolts have flat tips and require a nut or some other threaded object to snug against.
posted by humboldt32 at 3:25 PM on December 14, 2013

Sure you screw into things with bolts. This is exactly the situation to use a lag bolt, which basically looks like a really burly screw. Pre drill pilot holes and soap the threads to prevent work hardening(which can make your lag bolts brittle, exactly the thing to avoid with a dynamic load like a heavy sliding door)
posted by rockindata at 3:41 PM on December 14, 2013

Sure you screw into things with bolts. This is exactly the situation to use a lag bolt, which basically looks like a really burly screw. Pre drill pilot holes and soap the threads to prevent work hardening(which can make your lag bolts brittle, exactly the thing to avoid with a dynamic load like a heavy sliding door)

You can certainly screw into things with a lag (frequently called lag screws), but 1/4" thick lathe won't be worth much, and will likely be destroyed by the lag going through it. Even if it doesn't, there'll be a ton of deflection and the plaster will crack all over the place. Finding a joist and lagging into that will work much better.
posted by LionIndex at 3:51 PM on December 14, 2013

The concept of load bearing walls applies here and I doubt that the ceiling joists in an ordinary frame structure is going to be an adequate solution for hanging a heavy door. You might need some substantial reinforcement or you'll just pull your roof down. Ask someone who knows - an experienced house framer or architect - to have a look before you start drilling holes.
posted by three blind mice at 4:10 PM on December 14, 2013 [1 favorite]

The general construction in wood lathe ceilings is joists (big 2x8 or maybe 2x10 boards on edge) are spread out about every 16 inches apart. The strapping is nailed up into those at right angles, also about every 16 inches. So together, they create a gridwork. The lathe is mounted to the strapping at right angles to the strapping, so running the same direction as the joists. On the top floor, sometimes the joists are only 2x4's or so, because it wasn't expected to have a lot of load. (Joists are supporting the floor above - the ceiling is just to hide the joists, really)

That said, I don't think just the joists are going to be up for the job. You would probably need to pull down some ceiling and build up some structure to spread the load among several joists or something.
posted by rmd1023 at 4:12 PM on December 14, 2013 [1 favorite]

We recently installed two sets of hardwood and glass sliding doors about the same dimensions. Discovered we couldn't hang ours and ended up using rollers inset into the bottom of the door, some guides on the floor and a pelmet to keep the tops in place.
posted by Kerasia at 4:41 PM on December 14, 2013 [2 favorites]

Best answer: I've never found a stud finder that will work well in plaster/lathe. The fastest way to locate the joists is to draw a line where you plan to hang the door and then take a small, thin drill bit and run along, testing until you hit the joists. If the drill pops through, you obviously haven't hit a joist. All the holes will be covered by your track or else you can patch them pretty easily. I'd expect the joists to be on 16" centres.

If the track needs to run along parallele to the joists, you'll probably need to "sister" with a new piece of lumber (glued and screwed) If the joist isn't in exactly in the right spot, you'll need to install a new one, probably using joist hangars (metal straps available at home centres).

Pre-drill holes for you lag bolts with a bit equal to the thickness of the lag bolt minus
it's threads.
posted by bonobothegreat at 4:53 PM on December 14, 2013

I would not hang from old joists in the ceiling anything this heavy unless you pull the ceiling down, inspect the structure for integrity, reinforce the joists, making sure you're drilling into the center and the wood doesn't crack or split, etc.

I especially wouldn't do this blind in earthquake prone areas (like where I live in California!!)

Get a licensed contractor and plan to get a second or even third opinion on how to do this safely.

I am not a licensed contractor, but I've worked with many, ditto I've seen a lot of lath and plaster.

YMMV.
posted by jbenben at 5:07 PM on December 14, 2013

Best answer: At the very least, bolts alone won't do. You'd need mollies. But that's still not going to be strong enough.
posted by Chocolate Pickle at 6:16 PM on December 14, 2013

Best answer: I've been renovating houses in the 90-140 year old age range for about 7 years, professionally.

Are you trying to install barn doors that are the same height as the room, with no jamb? That is a very unusual thing to do. Interior doors are rarely that tall. Interior barn doors generally get installed in front of a cased opening. So...

You can install a header to carry the doors, then sheetrock over it. Depending on how wide the opening is, you'll need a 4x8 to 4x12 header. That header will be held in place by king studs and jack studs. Anchor the king studs to the walls either by getting lucky and finding two existing studs inside the walls that are directly across from each other, or by cutting open the walls and running blocking between stud bays.

What this will look like is 8 to 12 inches of new wall coming down from the ceiling, maybe more depending on the height of the doors. There will also be 4 inches of wall perpendicular to the existing walls.

If you really want a super clean installation of barn doors straight into the ceiling, with no surround whatsoever, get into your attic, find out the dimensions of your ceiling joists and whether they run parallel or perpendicular to the way the door will go, and re-ask the question. I make almost any scenario work, but I don't want to go through a bunch of hypotheticals without more info.
posted by MeanwhileBackAtTheRanch at 7:05 PM on December 14, 2013 [1 favorite]

Response by poster: Thanks, all. Excellent thoughts here (as always).

MeanwhileBackAtTheBeach, you have understood my situation. I've got an open span that I'm trying to seal off with the sliding doors, floor to ceiling.

I don't have attic access really (it's been finished off, and carpeted). It does seem like building a header is the smartest thing to do, and I appreciate your "professional renovator" advise! This is 150 year old farmhouse that's been pretty messed up over the years, and I'm just trying to make do with what's here...
posted by largecorp at 8:00 PM on December 14, 2013

Most barn doors are designed to be wall mounted, in front of an opening. That cased opening that I described also ends up being the overlap that makes the door completely cover what you're sealing off. If you hung it from the ceiling, you'd have to build out something to cover the gaps at the walls and ceiling.

Honestly, I'd have to see a detail of the track to offer any more advice other than: don't reinvent the thing unless you're willing to get very very involved and get professional help. I wouldn't be surprised if hanging the as-built track from the ceiling created problems besides too much load on a plaster ceiling.

Also: if you're rehabbing plaster and lathe, do yourself a favor: get a multi-tool, the vibrating saw kind. They're cheap, they have other uses, and for plaster almost every other tool lacks the necessary delicate touch. The multi-tool can cut a clean, shatter free line. Everything else will make a huge mess.
posted by MeanwhileBackAtTheRanch at 8:42 PM on December 14, 2013 [1 favorite]

The lath in old lath-and-plaster ceilings and walls isn't intended to support anything but the plaster. Hanging anything heavy from it will rip it right out. Even fairly light things can cause it to bend, which will crack the brittle old plaster. Once plaster is cracked, you're kind of screwed; in my experience, it's impossible to invisibly patch old plaster. Spackle-type products just don't have the same texture, it's really noticeable. I'm sure there are specialists who can do invisible repairs on plaster, but I'm equally sure that their work isn't cheap. Also, if your plaster comes un-keyed from the lath and starts to fall out, it's a pain in the butt to repair it in such a way as to make it stay put.

Personally, I wouldn't be comfortable installing anything more significant than a picture frame on old plaster. I wouldn't trust myself to be able to do it without busting up the wall/ceiling – plaster is quite hard and brittle, unlike drywall. Installing sliding doors is probably going to involve cutting out the plaster around where the door or header is going to be mounted (because if you end up sandwiching it in there I would expect it to eventually start cracking) and that's a pain in the butt to do well since not only is plaster hard and brittle, it also needs to be attached at the edges so that it doesn't flex.

I think this is probably a job for a professional who has experience renovating old houses.
posted by Scientist at 8:47 PM on December 14, 2013

I have a +/- 90yo house with plaster and two sets of heavy sliding doors. Both are installed in framing somewhat as MeanwhileBackAtTheRanch describes. Plaster repair people are expensive rarities nowadays and the stuff is so brittle -- beautiful, yes, but so finicky. Would not DIY and would put in framing if only to protect everything original to the house.
posted by kmennie at 7:30 AM on December 15, 2013

Tangential, but as far as finding studs in lath and plaster, you need a magnet (or a magnetic stud finder) to locate the studs by the nails in them. As long as you don't have metal lath, this works very well: get a ring shaped neodymium magnet. Tie a thread to it to find studs in walls by dragging it along the surface. Just swipe it in your hand to find ceiling joists. Make sure you are not finding pipes or wires: nails are not constant, though they will be in a line.
posted by oneirodynia at 1:03 PM on December 15, 2013