Guide to common surfaces you can & can’t plaster over & why…

This guide is designed to offer insight into the feasibility of plastering directly over different finishes found in your home.

While certain finishes may permit direct plastering, others may not, emphasizing the importance of discerning these variations to avoid costly errors.

If you're contemplating what surfaces are suitable for plastering, this guide provides comprehensive coverage of various finishes, providing clarity on each. Let's delve into each type individually.

Is Plastering Over Paint Possible?

Plastering over paint presents an opportunity to rejuvenate a space or mend a wall. Yet, before proceeding, several considerations must be taken into account to guarantee favorable results.

The condition of the existing paint layer is very important when contemplating plastering over it. If the paint remains intact and in good condition, skimming over it with plaster is generally feasible.

However, if the paint shows signs of age, flakiness, or damage, it's advisable to strip it away before plastering. Failure to do so may result in future detachment or cracking of the plaster.

To remove old paint, begin by cleaning the walls with a sponge and soapy water to eliminate debris, dust, and grease. Utilize a metal scraper to remove loose paint, and if stubborn areas persist, employ a sanding block. For particularly resilient paint, consider a chemical paint stripper.

Preparation Steps Thoroughly clean the painted surface with soapy water to remove dirt and grease, ensuring a clean base for plastering. Applying a coat of PVA emulsion serves as a crucial step to establish an adhesive bond between the surface and plaster.

Plaster Application

Proceed by applying the first layer of plaster, allowing it to firm up for 7-10 minutes before flattening trowel marks. Apply a second layer after 15-30 minutes, repeating the flattening process as needed. Depending on the wall condition, a third layer may be necessary.

Drying Time Patience is key as plastering requires ample drying time. Allow up to six weeks for full drying before applying any paint or wallpaper. Waiting at least a week is recommended before adding any further treatments to the wall.

Addressing Holes and Cracks Prior to plastering, address any wall imperfections such as cracks or holes. Small fissures can be filled with caulk, while larger ones may require professional intervention involving plaster and mesh.

In summary,

while plastering over painted surfaces is feasible, meticulous preparation and consideration of paint condition are essential for successful outcomes. By adhering to these steps, you can achieve a smooth, rejuvenated surface ready for further treatment.

Can You Plaster Over Plasterboard?

Plasterboard, also known as drywall, is a common material used in modern construction. When it comes to plastering over plasterboard, there are a few things to consider.

Skimming is the most popular way to get a smooth finish. It's quicker and easier than traditional plastering. Before you start, think about reinforcing the joints with scrim tape to prevent future cracks.

You don't always need a PVA base coat when plastering drywall. Just dampen the surface slightly with water. But don't overdo it, or you might damage the surface.

If the plasterboard is old, it might benefit from a layer of PVA first. Make sure to check how long it's been there before you start plastering.

When skimming plasterboard, two thin coats of plaster should do the trick. Wait for each coat to firm up before applying the next one.

In a nutshell, plastering over plasterboard is different from traditional methods. Skimming is the way to go, but don't forget to reinforce the joints and decide if you need a PVA base layer. Two thin coats should give you a smooth finish.

Is plastering over Artex possible?

Artex, a textured surface popular for ceiling decoration and wall texturing in the 1970s, has fallen out of fashion. Despite its previous popularity, it's now deemed outdated and challenging to repair or clean.

Plastering over artex surfaces can be done, but it demands careful attention to the texture's height and adherence to specific steps.

Is Artex Hazardous?

It's crucial to recognize that until the year 2000, artex materials were manufactured with asbestos, a highly hazardous substance. Asbestos is generally considered safe if undisturbed, but when disturbed, it releases toxic dust and debris that can cause severe lung damage and lead to serious illnesses.

Given these risks, removing artex should ideally be handled by trained professionals. However, if plastering over artex is your preferred approach, it's essential to carefully assess the texture height before proceeding.

Plastering Over Artex: Step-by-Step Guide:

Assess Texture Height: Determine if the artex texture protrudes significantly from the surface. If so, consider removing the bulk of it using tools like a floor scraper or wallpaper scraper to create a smoother base.

1. Prepare Surface:

   • Clean the surface thoroughly to remove any dirt, dust, or grease.

   • Apply a base coat of PVA emulsion to the entire surface. This helps create an adhesive bond between the base coat and plastering. To ensure even coverage, consider adding food coloring or plaster to the mixture for better visibility.

2. Apply First Plaster Layer:

   • Once the PVA base coat has dried but remains tacky, apply the first layer of plaster.

   • Wait approximately 7-10 minutes for the plaster to firm up before using a trowel to clean up edges and flatten the plaster. This step helps ensure an even surface for subsequent layers.

3. Apply Second Plaster Layer:

   • After 15-30 minutes, apply a thicker second layer of plaster over the first.

   • Clean up edges and flatten the plaster to achieve a smooth finish.

4. Apply Third Layer If Needed:

   • If the artex texture is still visible after the second layer, apply a third layer of plaster using the same process.

   • Ensure each layer is applied while the previous one is still damp to promote adhesion and prevent future cracking or flaking.

5. Maintain Proper Moisture Levels:

   • If you're unable to complete the plastering in a single day, lightly wet the dry plaster before applying the next coat. This helps prevent premature drying and promotes a stronger bond between layers.

By following these steps and maintaining careful attention to detail, plastering over artex can result in a smooth and refreshed surface while minimizing potential health risks associated with asbestos exposure.

Plastering Over Tiles

While plasterers may consider plastering over tiles, it's generally discouraged due to several reasons. Tiles pose challenges for plaster adhesion, with their slippery surface and poor moisture absorption leading to weak bonds and potential flaking.

Moreover, plastering over tiles complicates future drilling tasks, risking cracks and damage to the surface. If tile removal is feasible, it's recommended to opt for this approach to avoid future complications.

If tile removal isn't an option, using Blue Grit as a bonding agent is preferable to standard PVA. Apply a layer of Blue Grit as a primer, ensuring thorough drying before plaster application. Unlike PVA, Blue Grit requires only one coat.

In essence, while plastering over tiles is possible, it's best for plasterers to weigh the associated challenges and opt for tile removal when feasible. When removal isn't possible, using Blue Grit as a bonding agent ensures a strong and durable surface for plaster application.