Painting lime render

Painting lime render requires a specific approach to guarantee a long-lasting finish. Read on to find out how to prepare, prime and paint lime render effectively, ensuring superior adhesion and durability.

What Is Lime Render?

Lime render is a traditional building material known for its breathability and flexibility, making it ideal for older buildings and historic restorations. However, lime render can present several challenges when it comes to painting. One common issue is its chalking surface, which occurs as the lime reacts with the atmosphere, creating a dusty residue that can prevent paint from adhering properly. Additionally, lime render is more porous than modern cement renders, which means it can absorb moisture and cause paint to peel or blister if not correctly prepared.

Despite these challenges, a great, long-lasting paint job can still be achieved on lime render with proper preparation. Thoroughly cleaning and priming the surface is crucial to ensure the paint adheres well and withstands the elements. Without adequate priming, the paint may fail to bond with the lime render, leading to flaking, peeling and an overall poor finish. By taking the time to prepare the surface properly, you can ensure a durable paint job that preserves the integrity of the substrate.

How to paint lime render

Required Steps

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Step 1 - Prepare the surface
  • Start by thoroughly cleaning the lime render to remove dirt, dust or anything that will interfere with the adhesion of the paint. Remove loose, flaking material by scraping the surface with a stiff bristle brush to a sound edge.
  • Fill any cracks and small surface defects with an appropriate filler and allow to dry. Sand the area with a fine grade abrasive paper to create a more even base for priming. Remove any dust.
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Step 2 - Prime the surface
  • Use Zinsser Peel Stop to prime and seal the chalky surface of the lime render and create a stable base for the paint. Peel Stop is a superior primer because it binds down any loose or chalky material, preventing future peeling and ensuring that the topcoat adheres properly.
  • Apply Peel Stop with a brush or roller, making sure to cover the entire surface evenly and allow a minimum of 2 hours recoat time in normal conditions. Usually, one coat of primer is sufficient, but if the surface is highly porous, you may need to apply a second coat. After use, brushes can be easily cleaned with soap and water.
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Step 3 - Paint the surface
  • Choose a high-quality lime render paint that is breathable and suitable for exteriors. We recommend AllCoat Exterior (Water Based Matt or Satin). Use a brush or roller to apply the paint in even strokes, ensuring full coverage.
  • Ensure you paint in mild, dry weather. Avoid painting if rain is expected or if temperatures are below 10°C or above 32°C, as extreme temperatures can affect the drying process and paint adhesion.
  • Decorate with two full coats of AllCoat Exterior, allowing 1 hour drying time between coats. AllCoat Exterior is the ideal topcoat paint for lime render as it offers supreme protection to all exterior surfaces and is resistant to mould, rain and severe weather. AllCoat Exterior is available in white, black and ready tinted Anthracite Grey - RAL7016. It is tintable to any BS, NCS or RAL colour through the appropriate tint base.
  • Alternatively, if painting in low temperatures down to -5°C, decorate with AllWeather for excellent resistance against cracking, blistering and flaking.

Properly priming and painting lime render is crucial for delivering a high-quality, long-lasting finish. By starting with thorough surface preparation, and stabilizing the render with a primer like Peel Stop, you ensure that the topcoat adheres correctly and remains durable. With these best practices, you can confidently preserve the integrity of lime render while providing a superior, long-lasting paint job.

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The Pavilions
Bridgwater Road
Bristol
BS13 8FD
Company number: 04503854

Tor Coatings Ltd
21 White Rose Way
Follingsby Park
Gateshead
Tyne & Wear
NE10 8YX