Plastering and Plaster Repair

Since prehistoric times, plaster has been used in building constructions. Plaster walls and floors have been discovered by archaeologists dating back to 6000 B.C.. Plaster walls were used to paint the hieroglyphics from early. Plaster was the preferred ceiling and wall surface until World War II when gypsum-drywall became a popular choice.

While drywall is an historic development in building technology, it was more of an evolution than a revolution. Gypsum rock, which has been used to make plaster since ancient times, is the core material of drywall.

Plastering

Plaster repairs in auckland are the only topic in this section. It takes many years to master plastering. However, a hybrid lime plaster approach is an option to get the appearance and durability of plaster without the hassle. For plaster repair, you will need the same tools as for drywall repair: a drill or screw gun; 6 in. 12 in. Taping knives, a mason’s knife and a respirator are all necessary if you plan to remove or cut into plaster. Goggles are recommended for this job.

Anatomy and treatment of a plaster job

Traditional plastering involves several steps.

  1. Then nail the lath to your framing.
  2. Apply a plaster scratch coat to the lath. This coat is wet and oozes out of the lath. It then hardens into a key.
  3. After it has dried slightly, you can then twelve the brown coat and roughen it.
  4. Apply a white finish to the surface.

Plasterers used to mix animal hair with brown and scratch coats to stick in the past. Old plaster is very irritating to the lungs. For uniformity, the finish coat consisted of gauging plaster mixed with lime. For the next coat to stick to, it was necessary to scratch and scrape brown and scratch coats. Finish coats were thin (1/16 inch). It was very difficult.

The age of a house can be determined by its lath. Wood lath was first made from one board. This allowed the board to expand like an accordion when it was pulled apart side by side. Metal lath was made available in the late 1800s, but split-wood lath remained popular because it was easy to make on site. However, plasterers switched to gypsum plaster by 1900. This dried faster and was cheaper. Around the same time, plasterers started using small panels of gypsum coated with paper instead of metal or wood lath. The panels, also known as rock lath or gypsum lap, were so simple to install that they became the dominant market in the 1930s. However, technology and time keep improving. The residential use of plaster was almost eliminated after World War II when drywall took over.

Plastering

Cover any floors, baseboards or casings that are already in place with tape and paper to prevent plaster splatters.

Small Repairs

Tiny cracks and holes in plaster can easily be filled with patching plaster, or Fix-It-All (a super-strong, fast-drying patching compound). Joint compound is easier to work with because it sets faster than patching plaster and is soft. Setting-type joint compound is better than drying-type, which are less strong. Before applying compound, remove any paint from surfaces that you are repairing and lightly sand adjacent areas.

You can repair small cracks in plaster by stripping the plaster and cleaning off any loose plaster. Undercutting helps the patching material harden and forms a key that will not fall out. To bond the patch to the plaster, thoroughly wet the plaster.

Stretch a length self-adhering fiberglass wire over the crack. Use a tape measurer to apply the joint compound. The first coat of joint compound should be sanded lightly. It should be a bit rough to ensure that the second coat sticks better. Apply the second coat and feather it out to blend the edges.

After the patch has dries, lightly sand it with fine, 220-grit paper. Wipe it clean and dry it thoroughly. Finally, prime it with PVA primer.

Broken or large cracks are often accompanied by sections of sagging plaster that have pulled away from the lath. Plaster that is not crumbling can be reattached to the lath with type W drywall screws or plaster washers. These are designed to fit under the heads the screws. This operation can be done with a screw gun.

Before you attach the screws to the plaster, mark the locations and then use a spade bit or a spade bit for countersinking a hole of 1/8 inch. Each washer should be drilled to a depth of at least 1/8 in. The washers and screw heads will sink below the plaster’s surface. You can easily cover them with patching compound.

Screws and washers should be placed every 8 inches. To 10 in. On both sides of crack, and wherever plaster appears springy or disconnected from the lath, After stabilizing the crack this way, you can tape it and then fill it as previously described.

If the lath is still intact, small holes are very easy to fill. Brush off any plaster that isn’t needed, clean the area, apply a PVA bonder to the plaster and then trowel in the patching material. Let the first coat dry a bit rough and then apply bonder to it again.

You will need to put some lath in the hole if it has not been covered. Remove any plaster that is left around the hole’s edges. Cut a piece from metal lath that is larger than the hole. Then, loop a small piece of wire through its middle. Next, hold the ends of each wire and slide the lath into place. Pull the lath against the back of your hole by inserting a pencil in the loop. Turn the pencil like an airplane propeller to make the wire taut. The lath is held in place by the pencil that spans the hole.

After wetting the plaster and lath, apply a rough coat to the hole with compound. Once the compound has dried, loosen the wire and remove the pencil. Push the wire into the wall cavity. The metal lath will be held in place by the hardened plaster. Apply the final coat.

Large holes without lath should only be partially filled with a small piece of drywall. A square corner is easier to patch than a square one. Use an oscillating multitool and an abrasive wheel to square up plaster edges. Wear safety glasses. You must be careful not to remove the lath. Attach the drywall to the lath using type W drywall screws. Wrap self-adhering fiberglass tape around the perimeter and then apply joint compound or plaster as previously described. To get the best results, the drywall should not be thicker than the plaster to allow for feathering and building up.

These bolts and anchors can be used to attach light loads to plaster walls and drywall. Left to right: plastic anchor with screw and molly bolt; toggle bolt; drive anchor.

Pegboard can be used as a substitute. It is easy to cut with a handsaw and fit any irregular holes. A 1/4-inch sheet should be held. Place 1/4-in. of pegboard on top of the plaster. Next, trace the shape and size of the patch using the holes in the pegboard. Finally, screw the pegboard to its lath-textured side. The plaster will seep through the holes and harden the same way that plaster keys into spaces between lath strips.

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Written by empirebears

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