A Guide To Renovating Plaster

Renovating plaster is a specialist plaster used mainly for repairing and renovating old or damp walls. This material is used to tackle common issues, mainly found in older buildings, such as dampness, salt contamination, and poor adhesion of standard plasters. Here’s a comprehensive guide to what renovating plaster is, and how to use it:

Some key characteristics for renovating plaster:

1. Moisture resistance: Renovating plaster is designed to resist moisture, making it suitable for walls prone to dampness. It helps to prevent moisture transfer from the wall to the plaster surface.

2. Salt resistance: Old walls often suffer from salt contamination due to rising damp or other moisture problems. Renovating plaster contains additives that resist salt, preventing the salts from reaching the surface and causing efflorescence (the white, powdery residue).

3. Breathability: Unlike standard plaster, renovating plaster is breathable. It allows moisture to evaporate through the plaster, aiding in the drying out of damp walls without trapping moisture inside.

4. Adhesion: Renovating plaster has enhanced adhesive properties, allowing it to bond well to older, often compromised substrates where traditional plasters might fail.

5. Application: Typically, this plaster is applied in conjunction with a damp-proofing system, such as a damp-proof membrane or a chemical damp-proof course. It is often part of a multi-layer solution that includes a base coat and a finishing coat.

Where renovating plaster is used:

Renovating plaster is commonly used in the restoration of period properties and buildings of historic significance where damp issues are present. It is especially useful in basements, cellars, and ground floors where rising damp is prevalent. Its use helps to restore the aesthetic and structural integrity of the wall without making moisture issues worse.

Practical benefits:

• Improves wall durability: By addressing the root causes of damp and salt damage, renovating plaster extends the life of walls.

• Maintains aesthetics: Provides a smooth, workable surface that can be painted or decorated like traditional plaster.

• Protects building fabric: Helps to preserve the structural integrity of older buildings by preventing moisture-related damage.

Where to buy renovating plaster:

In the UK, renovating plaster can be purchased from a variety of suppliers including major builders' merchants such as Travis Perkins, Jewson, and Selco Builders Warehouse. It's also available at large home improvement stores like B&Q and Wickes. Additionally, specialist plastering suppliers and online retailers such as CPI Euromix and Amazon stock various brands and types of renovating plaster. For historic building projects, Lime Green Products Ltd and Mike Wye & Associates offer specialised renovation plasters tailored for heritage conservation. Many of these suppliers provide both in-store purchasing options and delivery services, ensuring convenient access to the materials needed for restoration projects.

How to use renovating plaster:

When using renovating plaster, it is crucial to follow the manufacturer's guidelines for preparation and application to ensure its effectiveness. This might include preparing the wall surface, applying a base coat or mesh, and finishing with a suitable top coat.

Applying renovating plaster involves several steps to ensure it addresses issues like dampness and salt contamination effectively. Here’s how to correctly apply renovating plaster: 

1. Preparation

Inspect the Wall:

• Identify dampness: Check for signs of damp, such as wet patches, mould, or efflorescence.

• Repair structural damage: Fix any structural issues before plastering. Ensure the surface is sound.

Remove existing plaster:

• Strip back to masonry: Remove any old, damaged plaster to expose the bare masonry.

• Clean the surface: Scrub off any loose debris, dust, and salts. You might use a wire brush or similar tool.

Treat Dampness:

• Apply damp-proofing measures: If needed, install a damp-proof course (DPC) or membrane.

• Use an anti-salt solution: If the wall has high salt content, apply a salt-neutralising solution and let it dry.

2. Applying the base coat

Mix the plaster:

Follow Manufacturer's Instructions: Mix the renovating plaster according to the manufacturer's guidelines. Typically, you will mix it with clean water to the right consistency.

Apply the first coat:

• Use a trowel: Apply the plaster directly onto the prepared wall with a trowel.

• Thickness: Apply at a thickness of about 10-15mm, or as specified by the manufacturer.

• Embed mesh (optional): For added stability, you may embed reinforcing mesh into the plaster while it’s still wet.

Scratch the surface:

Create a key: Scratch the surface lightly with a plasterer’s comb or similar tool to create a rough texture, which will help the next layer adhere.

Allow to set:

Curing time: Allow the first coat to partially set. This can take several hours depending on the product and environmental conditions.

3. Applying the top coat

Prepare the second coat:

Mix again: Prepare a fresh batch of plaster for the second coat.

Apply the second coat:

• Use a trowel: Apply the plaster over the base coat, usually at about 5-7mm thickness.

• Smooth the surface: Use a trowel or a float to smooth the surface to the desired finish.

Finishing:

• Ensure even coverage: Ensure the top coat is smooth and even. This might involve using a wet trowel to achieve a finer finish.

• Final checks: Check for any imperfections and rectify them while the plaster is still workable.

Drying Time:

Allow to dry: Let the plaster dry completely. This can take several days depending on the thickness and the environmental conditions.

Avoid rapid drying: Protect the plaster from draughts or direct sunlight to avoid cracking.

4. Decoration

Prepare for painting:

• Prime the surface: Before painting, apply a primer suitable for new plaster.

• Apply paint or wallpaper: Once primed, you can paint or wallpaper as desired.

Note: Ensure the plaster is fully dry before decorating to prevent moisture from getting trapped under paint or wallpaper.

By following these steps, renovating plaster can effectively restore and protect walls in older buildings, addressing issues with damp and salt contamination while creating durable and beautiful surfaces.

Beams takes extra care when renovating

In summary, renovating plaster is a modern solution tailored for the renovation and preservation of buildings that suffer from damp and salt issues, making it an essential material in the toolkit for heritage conservation and property restoration in the UK.

At Beams we respect older homes and renovate them using high quality renovating plaster. Our vetted contractors follow the process above to ensure your home is updated to the highest standard. 

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If you’d like to talk to use about any home renovation processes, by all means get an estimate for the work below and we’ll be in touch.

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