Got the plaster & lath blues? As you likely already know if you are reading this, plaster & lath walls pose a greater challenge than drywall for otherwise simple tasks such as hanging a picture. The standard ‘picture hook with a nail’ simply does not work.
For hanging pictures, I generally favour plugs & screws with a special hook that gets screwed to the wall in any event, but even still, plaster & lath can be annoying even for drilled plugs and screws.
Anatomy of a Plaster & Lath Wall
Your standard plaster & lath wall generally has 4 basic components that you may encounter: studs (vertical framing lumber), lath (wooden strips running horizontally, nailed to the studs), scratch & brown coat plaster over the lath (the crumbly stuff, often including animal hair or other fibers to help hold it all together), and the thin very hard top coat of plaster.
What We Encounter Drilling in to Plaster & Lath
When drilling through plaster and then lath, the different layers are easily recognizable by the feel of the drill. There is the initial resistance of the thin hard top coat, then the (usually) quick vaporization of the brown coat, followed by coming up against the lath, and possibly thereafter a stud (lath is only around 1/4 inch thick).
If your drill bit pops through the brown coat in to thin air, then you have hit a spot between laths. This is not a good area to insert picture hangers as there is not really any structural value to the plaster between pieces of lath.
Studs are the best places to attach a screw, as they provide by far the most structural stability. If you are hanging something heavy or something that will otherwise require maximum support, find a stud. Drill a small pilot hole to confirm stud location (behind the lath), then screw directly to that.
However, studs can be difficult to locate in plaster walls, and sometimes they just aren’t in the place you need your picture to be. In that case, you want to at least make sure you are attaching to a piece of lath and not to a space in between. Lath tends to range from around 1 to 1 1/2 inches wide, and is generally spaced around 1/4 – 3/8 inches apart. So chances are you will hit a piece of that while drilling your small pilot hole. If not and you hit a gap, try again – about 3/4 inch up or down.
OK, So I Now Know Where to Hang the Picture, But How?
Once you have confirmed a good location, drill a hole the appropriate size for your wall plug ONLY THROUGH THE PLASTER AND NOT THROUGH THE LATH. This is the whole magic of this tip right here – one of those easy-now-that-you-know-it things. Avoid the temptation to drill through the lath as well as the plaster to make the hole deep enough to be able to actually insert your wall plug all the way in. Instead, insert your plug to see how deep it will go before it hits the lath, then remove it and snip off the end a corresponding amount to permit it to then be inserted just as deep as the lath and flush to the wall.
If the plaster has gotten a little sloppy around the drill hole, insert some spackling around the snipped off plug to clean things up a bit, then screw your picture hook through the plug and the lath. Although the lath is not a large structural timber, a screw screwed through it provides a lot more support than one held only by the wall plug in the crumbly plaster.
Voila, a more secure picture hook.