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Can You Put Plaster Over Block Walls? (How To)

Block walls are sturdy and highly durable. Additionally, they are fire-resistant and energy efficient. However, block walls are prone to water damage and are not aesthetically appealing. You can use various methods to finish a block wall and improve its appearance. But can you plaster over it?

You can put plaster over block walls to enhance their appearance and lock out moisture. Repair any damage and clean the wall thoroughly to remove dust. Apply PVA Unibond and allow it to dry before applying a second coat.

You can successfully apply plaster over block walls as a finishing procedure to make them more appealing and lock out moisture to prevent damage. Inspect the walls for any holes or cracks and repair them before commencing the plastering work. Otherwise, they might show on the finished result and ruin your project.

Brush the wall to remove dust or debris that might ruin the plaster bonding. Apply a primer to improve plaster adhesion and let it dry for 24 hours. Apply a second coat and let it dry before applying plaster.

The rest of the article identifies any challenges you might face and the tools and preparations required to plaster over block walls. It also outlines the step-by-step process to have a successful project.

Should You Plaster Over Block Walls?

You can plaster over block walls, but it’s a delicate process with several challenges. The following section outlines the major problems to look out for when plastering over block walls and recommends ways to prevent them.

When plastering over block walls, you will likely face blistering, debonding, popping, loose plaster, efflorescence, or crazing. Prepare the surface, mix the plaster correctly, and allow enough curing time to prevent these problems.

Blistering may occur on a plaster characterized by the formation of small patches or swelling on the surface due to the late addition of water or uneven mixing of plaster. You can prevent it by mixing plaster appropriately before application.

The plaster may separate from the block wall in a debonding process, and it happens when you add a thick layer of plaster or plastering on a greasy or dusty wall. Therefore, you can prevent it by degreasing the wall, applying a primer, and applying the right plaster thickness.

Crazing forms a network of small cracks on the surface resembling a spider web. It happens due to fine particles in the mixture or plastering on a dry substrate. You can prevent it by purchasing high-quality plaster and good wall degreasing before application.

A plaster surface may form white crystalline substances and eventually get damaged, which is known as efflorescence. It occurs when moisture-containing salts seep on the surface. You can prevent it by drying the wall before application and using salt-free plaster.

Plaster may fall from various surface parts and leave patches. It occurs due to bonding failure between coats. Plaster may displace from the surface after impact due to improper mixing and curing time. You can prevent these problems by using the correct craftsmanship and high-quality plaster.

What Tools Do You Need to Put Plaster Over Block Walls?

Plastering over block walls can be successful when you have the right tools. It saves time and ensures excellent results. Read the section below to identify the tools you need to complete a block wall plastering project.

To plaster a block wall, you should have a broom, a notched trowel, a mixing bucket, a plaster stand, a spackle knife, plastic tarps, a plasterer’s hawk, a paddle mixer, a bucket trowel, and a float. Order the tools online or from your nearest home improvement store.

You should have a broom to brush over the block wall and remove dust and debris and a floating rule to check the level of the plaster surface. A mixing bucket will be handy when mixing plaster before application. The plastic tarps will catch any PVA or plaster spills to avoid staining the floor.

A paddle mixer is an essential tool when mixing plaster, and you will need a bucket trowel to scoop plaster from the mixing bucket. You will need a plasterer’s hawk to hold plaster, allowing easy movement to prevent spillage and wastage.

Although it’s unnecessary, you can get a foldable stand to place the mixing bucket for easy access to plaster when applying it over the walls. You will also need a spackle knife to spread plaster across the wall. Finally, you should have a plasterer’s float to smooth out and finish the plaster surface.

Copyright protected content owner: and was initially posted on November 30, 2022.

What Preparations Do You Need To Put Plaster Over Block Walls?

Plastering over block walls is a great way to create a unique finish. But before you can add this finishing touch to your walls, you must know what preparations to make. Read the section below to discover how to prepare for the project.

When plastering over block walls, remove any old paint and brush the wall to remove dust and debris. Repair cracks and degrease the wall to remove wax and contaminants. Apply a layer of PVA Unibond and leave it to dry for 24 hours. Apply a second coat before the plaster application.

If you are plastering on an old wall, remove old paint or plaster flakes and inspect the wall for any cracks or holes. Repair the damages with the appropriate material and use a wire brush to remove mold stains.

Brush over the walls with a broom to remove dust or debris, and wash the wall with sugar soap to remove grease, wax, or contaminants—lay plastic tarps below the wall to catch any spill and avoid ruining the floor.

Mix one part of PVA Unibond with four parts of water and apply it over the wall using a brush. Leave it to dry for 24 hours and apply a second coat before plaster.

Copyright article owner is for this article. This post was first published on November 30, 2022.

How To Put Plaster Over Block Walls

Although plastering over block walls should be left to professionals, you can save time and money and ensure impressive results by learning how to do it correctly. Read the section below to learn how to put plaster over block walls correctly.

To put plaster over block walls, mix plaster and apply the first coat. Spread it across the wall with a spackle knife and smooth it. Texture the layer using a notched trowel, apply the second layer, and smooth it using a float. Leave the plaster to dry according to the recommended time.

The following is a step-by-step process of plastering a block wall.

Step 1: Pour water halfway into the mixing bucket, open a plaster bag and empty the contents into the water. Mix thoroughly using a paddle mixer and ensure it’s thick, without particles.

Step 2: Scoop the plaster mixture from the bucket and load it into a hawk.

Step 3: Spread plaster across the wall using a spackle knife. Apply a thin layer first and add as required. Spread the plaster from the bottom to the top and work in sections for the best results.

Step 4: Smooth the first layer of plaster using a float and pay attention to the thick areas.

Step 5: Texture the first plaster layer using a notched trowel to create a good base for the second layer.

Step 6: Repeat steps 2 and 3 to apply the second layer of plaster 2mm thick. Smooth it with a trowel first and then finish with a float. Remove any holes, lumps, and inconsistencies to get a uniform finish.

Step 7: Remove the plastic tarps and allow the walls to dry for 5-7 days. Read the plaster manufactures instructions for the correct plaster drying time.

You can plaster block walls to improve their aesthetics and keep moisture out. Fix any damage and adequately clean the wall to eliminate any dust. Apply PVA Unibond, let it dry, then apply another layer before plaster.

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ReadyToDIY is the owner of this article. This post was published on November 30, 2022.

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