Render Accelerator

What is render accelerator and what is it used for?

Render accelerator is a specialist additive used to speed up the curing and drying process of certain render systems. It is commonly added to thin coat, silicone or acrylic renders to help them set more quickly, especially when working conditions are cooler, damper or less favourable for normal drying.

In some cases, render accelerator is also used with cement-based mixes to improve setting time and early strength development. This can help installers keep projects moving, reduce delays on site and achieve faster job completion without compromising the final finish when used correctly.

How does render accelerator work?

Render accelerator works by increasing the rate at which the render cures and hardens. In thin coat systems such as silicone render and acrylic renders, the additive helps reduce the time needed for the coating to dry through, making the surface more resistant to cold or damp conditions during the early stages of curing.

In cement-based products, certain accelerators alter the hydration process within the cement, helping the mix gain strength more quickly. This faster setting can reduce waiting times between stages and lower the risk of weather-related issues during curing.

What is EWI-020 Render Accelerator?

EWI-020 Render Accelerator is a liquid additive designed to reduce the curing time of silicone render and acrylic renders. It is intended to support rendering in cold weather or damp working conditions, helping the render dry more quickly while maintaining its appearance and performance.

When used with the correct dosage and mixed thoroughly, EWI-020 Render Accelerator can reduce drying time by up to 50%, making it a worthwhile investment for installers working through the winter months or during periods of unreliable weather.

Is render accelerator suitable for silicone render?

Yes, render accelerator is commonly used with silicone render where faster curing is needed. This is especially helpful in colder climate conditions, where the normal drying process takes longer and the risk of delayed curing is higher.

By helping the silicone render cure more quickly, the additive can support programme times on site and allow work to continue in a wider temperature range, provided all application instructions and weather restrictions are followed.

Can render accelerator be used with acrylic renders?

Yes, many liquid accelerator additives are suitable for acrylic renders as well as silicone systems. They are designed to reduce the curing time and support quicker drying in cool, damp or changeable weather.

This makes them useful for projects where appearance, consistency and speed are all important. Used properly, they can help acrylic renders achieve the desired final finish while reducing weather-related delays.

What is thin coat render accelerator?

Thin coat render accelerator is an additive developed specifically for thin coat render systems. These products are typically solvent-free and designed to reduce both curing time and drying time, helping installers complete work more efficiently in challenging site conditions.

Because thin coat systems rely heavily on correct moisture evaporation and curing, adding a suitable accelerator can help reduce risk during colder weather while still supporting the expected texture, colour and finish quality of the render.

Can render accelerator be used in cold weather?

Yes, one of the main benefits of render accelerator is that it enables rendering in colder weather conditions. It helps reduce the time that fresh render remains vulnerable to moisture, low temperatures and delayed curing, which is particularly useful during the winter months.

That said, render accelerator does not remove all cold weather restrictions. Installers should always refer to the product instructions, temperature range guidance and system recommendations before application, as some conditions may still be unsuitable for rendering.

Does render accelerator affect the final finish?

When used at the correct dosage and mixed thoroughly, render accelerator is designed to support faster curing without having a negative effect on the final finish. Products such as EWI-020 are formulated to help maintain both the performance and appearance of silicone or acrylic render in less-than-ideal conditions.

Incorrect dosage or poor mixing, however, can affect workable consistency, setting behaviour and finish quality. For that reason, it is important to follow the mixing instructions carefully and only use the additive as recommended.

How much quicker does render dry with accelerator?

The exact reduction in drying time will depend on the product, the render system, the substrate and the working conditions on site. Some thin coat and silicone render accelerator additives can reduce curing time by up to 50%, helping installers save valuable time during application.

On cement-based mixes, some accelerators can reduce setting time by as much as two thirds, although performance will vary depending on the mix design and dosage used. Always review the product details for expected results.

What is calcium chloride render accelerator?

Calcium Chloride Render Accelerator is a type of additive used to improve the performance of cement-based render, mortar, screeds and concrete. It works by accelerating cement hydration, helping the mix harden faster and develop early strength more quickly.

This can be particularly useful where faster setting is required or where there is a risk of frost damage during the early stages of curing. It may also help reduce shrinkage and cracking by improving early strength development, although the correct mix design and dosage remain essential.

Is render accelerator suitable for cement-based render?

Yes, certain accelerator additives are designed specifically for cement-based render. These products can help speed up setting, improve early strength and support faster progress on site, especially in cool conditions where curing would otherwise be slow.

They are often used in professional applications involving render, mortar, screeds and concrete, but should only be added in line with the manufacturer’s instructions. The type of accelerator used for cement systems may differ from products designed for silicone or acrylic render.

How is render accelerator mixed into the render?

Render accelerator should be added strictly in accordance with the product instructions. In liquid systems, the additive is typically introduced into the render bucket or mix and blended thoroughly using a suitable plaster mixer until a consistent, workable consistency is achieved.

Care should be taken not to over-dose or disrupt the balance of the render mix by adding the wrong quantity or too much water. Thorough mixing is important to ensure the additive is evenly dispersed throughout the material before application.

What should installers consider before using render accelerator?

Before using render accelerator, installers should consider the system type, substrate condition, temperature range, moisture levels and the expected drying conditions on site. Even with an accelerator, unsuitable working conditions can still affect performance, curing and appearance.

It is also important to check whether the additive is suitable for the specific render being used, whether any restrictions apply and whether the dosage has been adjusted correctly for the quantity of material being mixed.

Does render accelerator help prevent cracking?

In some systems, particularly cement-based mixes, render accelerator can help improve early strength development, which may reduce the risk of shrinkage and cracking during the early curing stage. This can be a useful benefit when faster setting is needed in cool or damp weather.

However, cracking can also be caused by poor substrate preparation, incorrect mix design, application in unsuitable conditions or insufficient curing control. Render accelerator should therefore be seen as one part of good site practice rather than a complete solution on its own.

How should render accelerator be stored?

Render accelerator should generally be stored in a dry place, protected from frost, direct heat and contamination. Keeping the bottle, tub or container sealed when not in use will help preserve the product and support the stated shelf life.

Storage guidance can vary depending on the additive, so it is always best to refer to the product label or technical details for exact instructions. Good storage is important to ensure the accelerator performs as expected when needed on site.

What safety measures should be followed?

As with any additive or construction chemical, basic safety measures should be followed when using render accelerator. Installers should wear suitable gloves and review the health and safety information before use, particularly when handling concentrated liquid additives or cement-based materials.

It is also sensible to avoid splashing, protect surrounding surfaces and keep the product out of reach when not in use. Full safety instructions should always be checked before mixing or application.

Need help choosing the right render accelerator?

If you are looking for render accelerator for silicone render, acrylic renders, thin coat systems or cement-based applications, our range includes products designed to support faster curing and more reliable cold weather performance. Whether you need an additive for a single bucket or a larger quantity for ongoing site use, choosing the right product can save time and improve results.

Browse the website for product details, stock, delivery, VAT and application guidance, or contact the team if you need help selecting a suitable accelerator for your render system.