Easy DIY Steps to Repair Cracked Plaster

Cracked plaster is a common household problem. A plasterboard can easily last for years if it is installed properly. But even top-quality plaster walls wear out or get damaged over the course of time.

You have the option of hiring a professional company that can help you with your repair needs related to plastering in Auckland or any other major city in New Zealand. However, you can even do it yourself. Repairing your plaster walls can be easy and you don’t need to have any special skills or prior experience. Have a look at following tips that will help you in doing it yourself:

  • Do your homework

Most of the times, it is the water that causes plaster to crack in the first place. Therefore, you need to be alert and make sure you fix any leaks or causes of moisture before performing repairs.. Even temperature plays an important role. It’s important to maintain optimum room temperature  — neither too hot nor too cold.

The room you are working in should retain this temperature at least 24 hours before plastering, to ensure that the walls are completely dry. It must stay at this temperature during plastering and until the plaster has completely set.

  • Examine the plaster cracks

While covering damaged plaster with drywall is cheaper, materials that are period-authentic maintain the integrity of an old house. You should start by examining the cracks and try to find out possible causes. Settlement over time is one reason for cracked plaster, another is key disintegration. This is where the plaster bulges out through the wood lath to create a bond. It can also be caused by poor-quality plaster, water damage or regular wear and tear.

  • Clean out the cracks

The first step in repairing cracks is cleaning them out. You can use a five-way tool or any other scraping device from your portable workbench. For large cracks with plaster falling out, get rid of the damaged plaster to reveal the binding course. Remove old plaster in the lath  completely, in order to establish a better binding course for the new plaster to adhere to.

  • Useand drywall screws on large cracks

Large cracks where the lath and plaster have been pulled away from the wall, can be re-secured using metal plaster washers and ordinary one and a half to two-inch drywall screws. This secures the existing plaster to the wood lath. Secure screws and washers diagonally on either side of loose plaster, about one and a half to two-inch from the crack.

  • Prepare a base-coat

Image credit: bptrends

Plaster repair involves two coats, a base-coat plaster for re-establishing the key-ways (space between the slats of the wooden lath) for a binding layer and a top-coat finish layer to offer a smooth surface. The base-coat is a lime-based plaster, also known as ‘brown coat’ that is mainly sand- or silicate-based.

Mix base-coat plaster with room-temperature water. With the help of an electric drill with a paint-paddle, mix the plaster and allow the mixture to sit for a few minutes as it starts to thicken.

  • Squeeze the base-coat into the cracks

Mist the lath lightly with water; be careful not to over-saturate the wood. This will prevent the lath from wicking moisture out of the plaster, causing it to dry quickly. Using a trowel, squeeze base-coat into the cracks and make sure it gets into the keys of the lath. Smooth over the crack and angle off the excess.

Depending upon humidity, the base-coat can take from two hours to one whole day in order to set up fully. Give it a few days to dry completely. Once the base coat has dried, sand to a smooth finish.

  • Apply a finish coat

The final step is to apply a finish coat. The finish coat is much finer than the base coat and has a high lime content that gives the plaster a sheen. Spread the finish coat evenly over dried coat. The finish coat can also be used alone to cover small, hairline cracks. Polish the plaster repairs by lightly spraying with water and smoothing over with grout float. Once the finish coat has dried, the newly repaired plaster can be given a fresh coat of paint or wallpapered.

So these are some DIY steps that can help you in repairing cracked plaster. Hope you find this article informative and useful.


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