Plaster walls are common in older buildings, possessing a character and density that differs significantly from modern drywall. Plaster is an application of lime or gypsum mixed with sand and water, typically applied over thin wooden strips called lath. This construction results in a wall surface that is brittle and prone to cracking when subjected to standard hammering or aggressive rotation of common screws. Attempting to hang artwork using conventional nails or anchors often results in crumbling plaster and an insecure mounting point, necessitating specialized techniques.
Selecting Appropriate Hardware
The selection of the correct fastener depends heavily on the weight of the artwork. For very light items, such as small framed photographs, specialized brass or steel picture rail hooks distribute the load without requiring deep penetration into the lath. These hooks feature a small, angled pin that pierces only the plaster layer, relying on the angled design to secure the object close to the wall.
For medium-weight paintings, specialized plaster wall hooks, sometimes called monkey hooks, offer a simple solution. These devices slide into a small hole and then rotate behind the plaster layer, using the wall’s thickness to secure the mounting point without needing to locate a wooden stud. They are designed to spread the pressure over a larger area of the plaster’s back surface, preventing localized failure.
For heavier pieces, such as large framed mirrors or oil paintings, the weight necessitates a robust anchor that secures into the structure behind the plaster. Toggle bolts or winged plastic anchors collapse to pass through the wall thickness, then spring open on the blind side to create a large bearing surface. This mechanism effectively clamps the anchor to the lath, distributing the pull-out force. Ensure the wings or toggles are large enough to span the gaps between the lath strips.
Step-by-Step Installation Technique
Installation must be executed carefully to prevent the material from cracking due to vibration or splintering. Mark the desired location with a pencil, then apply a small square of painter’s tape or masking tape directly over this spot. The tape stabilizes the brittle plaster surface, holding the material together and reducing surface chipping when the drill bit makes contact.
Select a drill bit slightly larger than the core diameter of your chosen anchor or screw shaft. When drilling, use a slow speed and minimal pressure, allowing the bit to shave away the material rather than aggressively push through it. If the spot is between laths, the bit will pass easily through the plaster. If a wooden lath is encountered, advance the drill slowly to avoid splintering the wood, which can cause the surrounding plaster to loosen.
Once the initial pilot hole is established, clean it of dust and debris before setting the hardware. If using a toggle bolt, the hole size must be large enough for the collapsed wings to pass through completely, and the anchor is then pushed until the wings spring open behind the lath. For a simple screw into a wooden stud, the pilot hole should be slightly smaller than the screw’s threads. Drive the screw in slowly and straight to avoid damaging the surrounding plaster.
Handling Weight and Repairing Damage
When hanging exceptionally heavy artwork, the safest and most secure method involves locating a wooden stud using an electronic stud finder. A stud provides a solid wood structure behind the plaster and lath, offering a significantly higher load-bearing capacity than any anchor alone. If the art piece is wide or heavy, utilizing a French cleat system mounted across two or more studs can distribute the weight horizontally.
Even with careful technique, minor damage such as small chips or hairline cracks can occur around the installation point. For these imperfections, a simple patching compound or lightweight spackling paste provides an easy remedy. Apply the compound with a putty knife, pressing it firmly into the crack or hole, and then wipe the excess material flat. Once the compound dries, the area can be lightly sanded and painted to conceal the repair.