How to re-hang a fallen hand railing on plaster walls?
January 6, 2006 11:26 AM   Subscribe

How to re-hang a fallen hand railing on real plaster walls?

My house is about 65 years old, with plaster walls. The railing going up the stairs was attached to the wall in 2 places with screws and plastic anchors. (Actually, the railing was attached to brackets, which attached to oval, wood "plaques", which were attached to the walls). The other day, as I walked up the steps, one end of the railing fell off the wall.

What's left now is the "plaque" and bracket that held up one end of the railing (at the top of the stairs). Halfway down the stairs is a big circle where the other "plaque" was. This circle is filled with crumbly plaster. The railing was only the length of half the stairs - there's a banister going the rest of the way.

Ideally I think I'd want to rehang the railing in the same place - using the bracket that's still up, and rehanging the old one where it was, covering up this whole. I have all the tools one would need but zero experience with plaster walls.

What do you suggest?
posted by kdern to Home & Garden (30 answers total)
clean out the cumbly bits, trying not to pull the whole wall off. fill in the hole. leave to dry. smooth. paint. drill and use screws into plugs.
posted by andrew cooke at 11:29 AM on January 6, 2006

How are the plaques attached to the walls? For a hand rail they need to connect with a stud behind the plaster.
posted by LarryC at 11:51 AM on January 6, 2006

oh. i was assuming brick with plaster, sorry (i guess that's more a uk thing).
posted by andrew cooke at 11:52 AM on January 6, 2006

I also have plaster walls and I've used toggle bolts with great success when wall studs have not been where I needed them. Here is a page about various types of wall anchors; they seem to like toggle bolts, too.
posted by Alison at 11:57 AM on January 6, 2006

Be careful, as there are different kinds of repair compound out there. Some dry so hard that they can't be sanded.

For example, my local hardware stores stock both CGC Sheetrock and CGC Durabond repair compound.

Sheetrock 20 and Sheetrock 90 can be sanded. Durabond cannot be sanded. Well, at least not by mortal humans.

Otherwise, follow andrew cooke's directions. Plaster isn't hard to work with, at least not for small repairs like yours.
posted by GuyZero at 11:57 AM on January 6, 2006

Clean out the hole. Cut a piece of drywall to pretty much fit. Screw it to the lath that you exposed behind the plaster. Fill and smooth the gaps with drywall tape and joint compound. Sand smooth, paint. When you reattach the wooden plaque, use those wall hangers that go all the way through the wall and grab the backside.
posted by chazlarson at 12:01 PM on January 6, 2006

I'm getting mixed advice from you all here... anybody actually done this before?
posted by kdern at 12:36 PM on January 6, 2006

Remember - I have PLASTER walls, not drywall. I don't think toggle bolts will work.
posted by kdern at 12:37 PM on January 6, 2006

you have to describe what is behind your PLASTER.
posted by andrew cooke at 12:39 PM on January 6, 2006

Is it lath & plaster?
posted by yerfatma at 12:50 PM on January 6, 2006

I don't know what's behind the plaster - it seems to be several inches deep. It looks like just plaster to me... all crumbly.
posted by kdern at 12:55 PM on January 6, 2006

It certainly doesn't look anything like the photos on this page.
posted by kdern at 12:59 PM on January 6, 2006

I lived in a 1926 house with plaster-on-lath walls for 13 years. I repaired many instances of the "chunk-of-plaster-falls-out" scenario. The method I described is the one I generally used.

In my case, the walls were plaster over wooden lath. If the chunk were small and cosmetic, I would just fill it with joint compound. If it were larger, I'd clean out the hole, which would leave the lath in place, fill most of it in with a chunk of drywall [screwed to a stud if available or the lath if not], then fill the gaps with joint compound, sand, seal, paint.

If it were a situation like yours, where something's going to be fastened to the wall at that point, I'd fasten the thing will toggle bolts, putting them all the way through the plaster/drywall and the lath behind it, so it wouldn't just pull out again.

If you've got plaster over metal lath, it might be trickier. In that case, I'd probably still use the same basic method, but maybe I'd fasten the drywall "plug" to the lath with construction adhesive.
posted by chazlarson at 12:59 PM on January 6, 2006

Plaster over Lath? You still want to find the studs and attach to them.

Plaster over brick or concrete? Masonry anchors. Drill through the plaster into the masonry, and install the anchor in the masonry.

Do not attach the railing to just plaster, using any kind of anchor; it just is not strong enough.
posted by Kirth Gerson at 1:02 PM on January 6, 2006

If you're forced to use wall anchors, toggle bolts are your best bet. They’re designed to work on either drywall or plaster and may be used when the wall is hollow and has sufficient space behind it to accommodate the toggle.

In your case where you have plaster, there are probably 4 alternatives:
1. Plaster over lathe (thin horizontal wooden slats), with lathe attached to studs.
2. Plaster directly onto brick.
3. A hybrid, where you have plaster on lathe, which is then attached to brick using attached to the brick using a frame.
4. Plaster on metal lathe.

In scenario 1, you’d be best to attach the handrail to a stud, if there’s one exposed by the hole. If not, I’d recommend doing a variation on what Chazlarson said. To start with, make a sufficiently large hole that you expose the studs on either side of the hole. Then attach a piece of drywall to both studs (if you wanted to do a simple repair and just repair the hole, his suggestion would be fine, but given you want to attach a handrail to it, the lathe won’t be sufficient since it’s not intended to be load bearing). Once you’ve done that, use joint compound to blend it to the existing plaster and then use toggle bolts through the drywall.

In Scenario 2, assuming the brick is still in good enough shape (I.e. not crumbling), I’d recommend screwing / bolting the handrail directly into that using masonry anchors (having patched the hole first with joint compound). Ideally with brick, it’s better to screw into the mortar between the bricks, but in an older house, the mortar is probably likely to be worse shape than the bricks themselves.

In Scenario 3, you’ll probably have to do the bolts/screws into the brick, since the frame will not be strong enough to support the stress put on the handrail.

In Scenario 4, not sure what to do. I don't have experience with metal lath.

Hope this helps.
posted by Mave_80 at 1:16 PM on January 6, 2006

I don't think they were using metal lath 65 years ago.

A lathe is a tool for turning work. Lath is strips of wood for plaster walls. The 'A' in lathe is long. The 'A' in lath is short.
posted by Kirth Gerson at 1:20 PM on January 6, 2006 [1 favorite]

None of this sounds like it's going to work in my situation. I don't think there's anything behind the plaster - it's just crumbling plaster. The hole is about 3/4" deep and there's no wood, brick or metal.

The wall is not a full wall... it's kind of like the wall on the right side in this photo (not my house).

Are you saying that if I dig far enough through the plaster, there has to be some kind of lath behind it?

Hung before I bought the house, the railing was attached only to the plaster, with screws about 1" long.
posted by kdern at 1:25 PM on January 6, 2006

Oops - here's the link: "The wall is not a full wall... it's kind of like the wall on the right side in this photo (not my house). "
posted by kdern at 1:25 PM on January 6, 2006

Yes, there has to be something behind all that plaster. The typical plaster wall is a thin surface plaster ("white") over a thicker subsurface plaster ("brown") over either wood lath or brick. The brown plaster can be kinda think, but I would expect it to be less than an inch. But I'm no plaster professional.
posted by GuyZero at 1:29 PM on January 6, 2006

There still has to be some kind of framing to hold the plaster up. And if you say there's no lath and no masonry behind the plaster, then it has to be drywall. You can't plaster on air.

Find the studs; there's one at either end of your wall, and almost certainly more in between.

Those little magnetic stud finders do work. They locate the nails that hold the drywall or lath onto the studs. They're cheap.
posted by Kirth Gerson at 1:31 PM on January 6, 2006

Kirth Gerson: Never could spell properly.... Also fair point on the metal LATH - only reason I brought it up was because somebody else mentioned it earlier!

kdern: Am guessing you should still have studs in that. Plaster can get pretty thick sometimes, sometimes well over an inch thick, so I'd experiment deepening the hole. Something has to provide a frame for the plaster to be on. On preview, Kirth Gerson's got it.
posted by Mave_80 at 1:35 PM on January 6, 2006

Adding to what other people have suggested. Use the hardest patch you have that you can reasonably sand. A firm surface will resist torque and keep the plaster from crumbling again, though it sounds like the ovals could mitigate against that somewhat, provided they are a few inches in diameter.

I would go beyond simply trying to screw into the lath. Lath isn't usually very tough wood and might not hold the screw well, especially since the lath is in strips, so the chance of putting a screw into a gap, or near the edge of a strip is high.

I'd go with one of the anchors that expands fully against the far surface of the wall, rather than the type that simply try to wedge against existing material. Toggle bolts suck because they need a pretty big hole, and they all have to be inserted pretty much at once. Those winged plastic answers are better, but still need a big hole.

I like the molly-style anchors for permenent high-wear things, like railings. Just make sure you get a size that is appropriate to the depth of the wall material. The most common varieties are intended for drywall and may not expand deep enough for plaster & lath.
posted by Good Brain at 1:36 PM on January 6, 2006

Sheetrock 20 and Sheetrock 90 can be sanded. Durabond cannot be sanded. Well, at least not by mortal humans.

Kal-El, where are you when we need you?
posted by WCityMike at 1:40 PM on January 6, 2006 [1 favorite]

One more question - if I use drywall to fill the hole, how do I get it to be flat with the rest of the wall? Do I dig the hole down to the lath and then use plaster to build up some thickness before putting the drywall on?

And then once the drywall is on, it sounds like you're all recommending that I reattach the railing to the studs OR over the repair with molly or toggle bolts that go through the drywall, plaster underneath the drywall (if any) AND the lath. Is that right?
posted by kdern at 1:44 PM on January 6, 2006

Dig down, attach drywall to studs. Then use joint compound / plaster OVER the dryall to get it flush with the existing
plaster. Since the drwyall is attached to the studs directly, you can now use toggle bolts to attach the handrail to the drywall (if the handrail bracket does not line up with the stud itself.)
posted by Mave_80 at 1:53 PM on January 6, 2006

OK - now I understand. Thank you all for your help!
posted by kdern at 2:06 PM on January 6, 2006

Is the plaster on a wall that might be brick behind it? I've seen plaster layered on several inches thick onto brick without the need for lathe.
posted by john m at 2:51 PM on January 6, 2006

I will say it again: Don't attach the railing to the plaster. Don't, don't, don't attach it to drywall. If you do, you'll be doing this again. Find the studs and attach it to that.

I'm not sure you're clear on some of the terminology. Unless the hole is huge, like several inches across, you're going to use patching plaster to fill it, not drywall. Drywall is sheet gypsum with paper covering, in 3/8 or 1/2-inch thickness. Using it to fill a small hole is actually trickier than using patching plaster.

Yes, I have done this. If the hole is big, back up the patch with screen or even heavy paper on the back of the wall, then build up the patch in layers. When it's all higher than the surrounding wall, sand it down and paint it.
posted by Kirth Gerson at 3:39 PM on January 6, 2006

Kirth has it. Somewhere behind your wall, probably about 18 inches apart, are vertical wooden 2x4s called studs. These are what hold your house up. A stair rail takes a lot of pressure when someone leans on it, it has to be attached to the studs. The previous owner didn't do this, and that is why it failed.

Studs can pretty hard to find behind plaster. Try tapping firmly on the wall, perhaps with the handle of a hammer. A change in the sound, from hollow to solid, indicates a stud. If you aren't sure, try driving a small finishing nail and see if you hit the stud.

Hopefully, the studs will be where you need them!
posted by LarryC at 8:30 PM on January 6, 2006

Here's an update for posterity. I didn't do any of the following... I hired a contractor to do it for me.

I think he filled in the hole with plaster a couple times, let it dry, and sanded it down. Then I think he used toggle anchors to attach the railing.
posted by kdern at 8:27 AM on May 30, 2006

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