Here are two quick fixes for cracked and sagging plaster.
Time Varies
ComplexityIntermediate
Cost$50 - $150
Introduction
Repair sagging, cracking plaster walls and avoid the mess of demolition. With plaster washers and wide fiberglass mesh, old plaster walls can be made smooth and solid again.
Plaster sags from ceilings or bulges from walls when the plaster keys embedded around the wood lath break loose. To repair plaster walls, you’ve got two choices. You can break out all the loose stuff and replaster the area—not a do-it-yourself project. Or, you can stabilize the sagging plaster by using plaster washers to pull it back up against the lath. Plaster washers don’t always work, but they’re cheap, so it’s worth a shot.
If you have solidly attached plaster with cracks spider-webbing through your walls and ceilings, another option is to stabilize and coat the entire surface with another product—wide sheets of fiberglass mat.
Ahead, learn these two methods to repair sagging or cracked plaster walls.
Tools Required
- Cordless drill
- Mud pan
- Paint roller
- Roller sleeve
- Taping knife
- Utility knife
Materials Required
- Fiberglass mat
- Joint compound
- Nu-Wal plaster repair system
Project step-by-step (3)
Step 1
Reattach loose plaster with plaster washers
- First, locate the joists or studs and mark their location in the loose area.
- Push up the loose plaster and place 2-in. screws and the perforated plaster washers into the joists or studs about every 6 or 8 inches.
- Tighten the screws, which will cause the convex washer to flatten.
- Note: If the plaster has a rough surface, you may need to first scrape the surface to get the washer to lie flat.
- Next, secure the loosened field to the lath between joists with more washers.
- Finally, skim-coat over the washers with drywall joint compound.
- Note: Creating a smooth finish or mimicking the existing texture may take several coats and extra effort.
Step 2
Apply fiberglass mat
Fiberglass mats can cover cracking in well-adhered plaster walls. Self-stick mats are available at home centers. You simply stick them to the wall or ceiling and then skim-coat the mat (detailed in the next step).
Another system, called Nu-Wal (pictured above), uses a slightly different method. First, you roll on a latex-like base coat. Then embed the fiberglass mesh, and roll over it again. This method essentially gives your plaster walls a new flexible skin so non-structural cracks won’t reappear. Plus, it acts like a vapor barrier, keeping moisture from migrating into the wall, and it’s approved for lead paint encapsulation on interior walls.
Step 3
Topcoating the fiberglass
Skim-coat the fiberglass mat with two to three coats of joint compound.
However, if you’re using the Nu-Wal product, roll the special topcoat over the fiberglass mesh per the product instructions.
Originally Published: December 04, 2017
