When considering external wall finishes for your property, you might wonder whether silicone render provides insulation benefits. This question comes up frequently among homeowners and commercial property owners planning renovation projects or new builds. Understanding the thermal properties of silicone render helps you make informed decisions about your building's energy efficiency strategy.
Silicone render is a modern external wall finish that combines cement, aggregates, and silicone resin to create a durable, weather-resistant coating. So, what is silicone rendering? It's the process of applying this advanced render system to exterior walls, delivering a finish that offers superior water repellent properties whilst maintaining breathability. This finish typically gets applied in thin layers over prepared substrates or external wall insulation systems.
The material contains silicone resins that give it flexibility and crack resistance. These properties make silicone render particularly suitable for areas with challenging weather conditions. The finish comes in numerous colours and textures, making it popular for both domestic and commercial applications.
Silicone render on its own provides minimal thermal insulation. The coating typically measures just 1.5 to 3mm thick when applied. A 2mm layer of silicone render has an approximate thermal resistance of around R 0.003 m²K/W, which changes a wall's U-value by well under one percent.
This thin application means that silicone render cannot meaningfully reduce heat transfer through walls when used alone. The thermal conductivity of the material itself does not offer significant resistance to heat flow. However, this doesn't mean silicone render lacks value in energy efficient building strategies.
The real energy efficiency benefits of silicone render emerge when we use it as part of external wall insulation systems. In these applications, silicone render serves as the weatherproof protective layer over insulation materials that provide the actual thermal performance improvement.
External insulation systems typically use insulation boards made from various materials. Graphite EPS (expanded polystyrene) offers thermal conductivity around 0.030 to 0.032 W/mK, whilst standard EPS performs at approximately 0.036 W/mK. Mineral wool insulation materials achieve conductivity values between 0.036 to 0.040 W/mK, and high-performance phenolic foam reaches 0.020 to 0.023 W/mK.
When we apply silicone render over these insulation materials, it protects the insulation layer from weather damage whilst allowing the system to breathe. This protection ensures the insulation materials maintain their thermal performance over time.
Adding external wall insulation with silicone render finish can dramatically improve a building's thermal performance. On a solid brick wall, installing approximately 100mm of EPS insulation can reduce the U-value from roughly 2.0 W/m²K to around 0.30 W/m²K. With phenolic foam insulation, 60 to 80mm thickness can achieve similar performance levels.
For a typical 100m² wall area on a solid wall property, reducing the U-value from about 2.0 to 0.30 W/m²K cuts steady-state heat loss through that wall by roughly 85 percent. This substantial reduction in heat loss translates directly into lower energy bills and improved indoor comfort.
The silicone render acts as the durable, breathable outer skin that maintains these performance levels throughout the system's service life.
Keeping walls dry matters as much as insulation thickness for thermal performance. People often ask, is silicone render waterproof? While it’s not a completely impermeable barrier, silicone render's water repellent nature helps shed rainwater, keeping the wall assembly drier. Dry walls conduct less heat than damp ones, so we can expect a 5 to 10 percent improvement in real-world thermal performance compared to identical walls that stay damp.
This moisture management capability of silicone render becomes particularly important in the British climate, where driving rain and high humidity can compromise building performance. The self cleaning properties of silicone render also help maintain the appearance and function of the external wall system over time.
Silicone render offers excellent flexibility and crack resistance compared to traditional renders. A common question is, does silicone render crack? While no system is entirely immune, silicone render is specifically engineered to accommodate minor movement and significantly reduce the risk of cracking. This flexibility helps maintain the continuity of the insulation layer over time. Fewer gaps and hairline cracks mean fewer cold spots and less convective looping in cavities at junctions between building elements.
This long-term performance stability ensures that energy efficient benefits persist throughout the system's lifespan. Traditional renders may crack and allow moisture penetration, which can reduce insulation effectiveness and create thermal bridges.
External wall insulation finished with silicone render often improves winter comfort just as much as energy consumption figures suggest. Interior wall surface temperatures can rise by 2 to 4°C after upgrading, which reduces radiant chill that occupants feel when sitting near cold walls.
Summer comfort benefits also apply. Light coloured silicone render finishes reflect more solar heat gain, whilst darker colours absorb more heat. Choosing lighter shades can reduce facade surface temperatures by 10 to 20°C on sunny days, helping reduce overheating risk for south and west-facing elevations.
Whilst air sealing isn't the primary function of silicone render, a new mesh-reinforced basecoat plus finish can reduce draughts through existing hairline cracks by around 5 to 10 percent at common air leakage paths. These improvements typically occur around window reveals and service penetrations.
Mineral wool insulation behind silicone render finishes provides acoustic benefits alongside thermal improvements. Many building owners can expect external noise reductions of around 3 to 7 decibels, depending on the insulation thickness and wall build-up.
Moisture safety improves significantly when combining external insulation with silicone render systems. The low water uptake at the surface reduces freeze-thaw cycling in the basecoat and protects the insulation layer. Many ask how long does silicone rendering last — when properly installed and maintained, these complete systems typically offer service lives in the 25 to 30 year range.
If repainting becomes necessary over time, only vapour-permeable, silicone-compatible coatings should be used. Non-breathable paints can trap moisture behind the finish, which undermines both thermal performance and visual appearance of the system.
When comparing render materials for external insulation systems, silicone render offers several advantages over acrylic renders, cement render, and lime render. Acrylic renders and polymer renders may not provide the same level of flexibility or weather resistance as silicone-based systems.
Cement render applications often crack more readily and don't offer the same water repellent properties. Traditional renders may require more frequent maintenance and don't maintain consistent indoor temperature control as effectively.
The value of silicone render alone remains low compared to dedicated insulation materials. However, when properly applied over external insulation, the combined system delivers significantly better insulation than walls with just traditional render finishes.
External wall insulation systems with silicone render finishes represent cost effective solutions for improving building energy efficiency. Homeowners often ask how much does silicone rendering cost in Newcastle—while prices vary depending on property size, access, and finish type, the long-term savings in energy and maintenance make it a worthwhile investment. The initial investment pays back through reduced energy bills over the system's service life.
Proper maintenance requirements remain minimal compared to traditional render systems. The self-cleaning properties and weather resistance of silicone render reduce long-term maintenance costs whilst maintaining the building's aesthetic appeal.
Improved insulation properties from external wall insulation systems help reduce a building's carbon footprint significantly. Less energy consumption for heating means fewer greenhouse gas emissions from fossil fuel use.
The better insulation achieved through these systems supports the use of renewable energy sources like solar panels or heat pumps. When buildings require less energy for heating, renewable systems can meet a larger percentage of total energy needs.
Many benefits extend beyond just thermal performance. The durability and longevity of silicone render systems mean less frequent replacement compared to other materials, reducing environmental impact from manufacturing and transport.
To apply silicone render effectively over external insulation requires proper preparation of the existing substrate. Professional installers ensure correct installation of insulation materials, base coats, reinforcing mesh, and final render coats.
Thermal bridges need careful attention during installation to maintain system performance. Proper detailing around windows, doors, and other penetrations ensures the insulation system works as designed.
Just a few hours of poor weather during application can compromise system performance, so timing and weather conditions matter significantly for successful installations.
Many property owners believe that any external render provides meaningful insulation. This misconception can lead to unrealistic expectations about energy saving benefits from render-only applications.
Understanding that silicone render offers protective layer functions rather than direct insulation helps set appropriate expectations. The thermal performance benefits come from the insulation materials behind the render, not from the render itself.
Some people assume that silicone render requires special preparation or incompatible with certain wall types. Professional assessment can determine suitability for most external walls when proper installation methods are followed.
When considering external wall improvements, evaluate your property's current insulation levels and thermal performance. External wall insulation systems with silicone render work particularly well for solid wall properties built before modern building regulations.
Consider your personal preferences for maintenance requirements and appearance. Silicone render systems offer long-term performance with minimal upkeep compared to many other materials.
The visual appeal of silicone render finishes can enhance property values whilst delivering energy efficiency improvements. The wide range of available colours and textures allows customisation to suit architectural styles.
Determining the best approach for improving your property's energy efficiency requires professional assessment of your specific situation. Factors like existing wall construction, local climate conditions, and planning requirements all influence the optimal solution.
At Rendering Newcastle, we specialise in external wall insulation systems with high-quality silicone render finishes. Our experienced team can evaluate your property and recommend the most suitable approach for achieving your energy efficiency goals whilst enhancing your building's appearance.
Contact Rendering Newcastle today for a free quote on your external wall insulation project. We'll help you understand the thermal performance improvements possible for your property and provide detailed recommendations tailored to your specific needs.
