What's inside
As an Amazon Associate I earn from qualifying purchases. This post may contain affiliate links at no extra cost to you.
Lath and plaster can hold a small shelf securely, but it is less predictable than drywall. Behind the hard plaster is a thin wooden lath layer, and a drill may meet plaster, wood, a gap, or a stud. The best anchor depends on what the screw will actually bite into—and on the shelf’s total loaded weight, not just the shelf itself.
As an Amazon Associate we earn from qualifying purchases at no extra cost to you.
What we cover
Choose the right fixing before drilling
For a small shelf holding light items, first check whether a bracket can land on a stud. A screw into sound framing is usually the most reliable option. If the bracket holes do not line up with a stud, a toggle-style anchor can work in a hollow space, while a screw into intact lath may be adequate for a very light load. Avoid assuming that a drywall anchor’s published rating applies to plaster and lath; ratings are system- and material-specific.
Weigh the shelf and its intended contents. A 3-pound shelf with 10 pounds of books is a 13-pound load before accounting for leverage. A shelf that sticks far out from the wall pulls harder on its upper fasteners than a flat picture does. For anything heavy, valuable, or likely to be bumped, fasten into studs or add a support rail secured to multiple studs.
Anchor options at a glance
| Fixing | Best use | Main trade-off |
|---|---|---|
| Wood screw into stud | Any shelf where a stud lines up | Bracket holes may need adjusting |
| Toggle bolt or strap toggle | Hollow bay with enough clearance behind the wall | Needs a larger hole; can be awkward if the cavity is blocked |
| Screw into sound lath | Very light shelf, with the screw centered on a lath strip | Lath is thin and can split or loosen |
| Plastic expansion plug | Generally not the first choice for lath and plaster | May not expand properly in brittle plaster or a hollow bay |
A strap toggle anchor kit is a practical choice for a hollow section when a stud is out of reach. The straps pull a metal channel against the back of the wall, spreading the load over a larger area than a basic plastic plug. Check the package’s required hole size and wall-thickness range before buying.
Find studs and lath carefully
Use a stud finder as a clue, not proof. Dense plaster, metal mesh, wiring, and uneven surfaces can confuse electronic sensors. Confirm a likely stud with a magnet: it may locate the nails holding lath to studs, which appear in a vertical line. A strong rare-earth magnet is useful for this check. If the shelf bracket allows it, verify the position with a small pilot hole where the bracket will cover it.
Lath strips often run horizontally, with studs behind them running vertically. A screw that catches a lath strip may hold a very light load, but it is not equivalent to a screw embedded in a stud. If a pilot hole suddenly meets firm wood after passing through the plaster, stop and check whether you are at a stud or only lath. For a stud connection, use a wood screw long enough to pass through the bracket and plaster and enter the stud by about 1 to 1½ inches, while avoiding hidden services.
Drill without cracking the plaster
Start with a sharp masonry bit and a drill set to rotation-only—no hammer action. Hammer mode can chip the plaster face or loosen the bond between plaster and lath. Drill slowly with light pressure, and use a bit sized to the anchor maker’s instructions. Keep the hole away from the edge of a lath strip when possible; wood screws close to an edge can split it.
Plaster dust can hide the change from plaster to wood. Keep the drill straight, clear dust from the hole, and do not force an anchor that will not fit. If the plaster crumbles or the hole grows wider than intended, do not rely on that hole for a loaded shelf. Move the bracket if possible, or use an anchor designed for a hollow cavity with a sound surrounding wall. A short carbide-tipped masonry bit set can make controlled pilot holes; a long bit is usually unnecessary for this task.
Install and test the shelf
Mark the bracket holes level and check for pipes or cables before drilling. For a toggle anchor, drill the specified diameter, insert the channel fully, and pull the straps snug so the channel sits flat behind the wall. Break off the straps as directed, then tighten the screw until secure. Do not overtighten: crushing plaster can weaken the fixing, and a spinning anchor is a sign to stop rather than keep turning.
Install every fastener the bracket requires. Tighten screws evenly, then load the shelf gradually while watching for movement, new cracks, or a bracket pulling away from the wall. A small shelf for keys or a few light objects may be fine with sound lath or suitable toggles. For books, cookware, or anything heavy enough to hurt someone if it falls, use studs or a properly supported rail instead of asking a plaster face or thin lath to carry the load.