Atlas Gemini RS White Silicone Render 25 kg — BBA-System-Compatible, Fibre-Reinforced Facade Finish

Product Overview

A premium white-base silicone render engineered for facades where long-term colour brightness and maximum pigment clarity matter most, Atlas Gemini RS White 25 kg delivers the same fibre-reinforced 4K aggregate technology (four specially graded minerals that make the render faster to apply and longer-lasting on the wall) and siloxane-enhanced resins (the high-performance polymer behind its self-cleaning, water-repellent surface) as the rest of the Gemini RS range — in a brilliant white base optimised for light, pastel, and neutral SAH shades. Part of the premium silicone render collection, it combines 3D-Flex elasticity with Mirror Effect UV protection and Biosec bio-shielding to keep residential and commercial elevations looking pristine for decades with minimal upkeep.

Coverage starts at ≥ 2.3 kg/m² by hand (approximately 10.9 m² per 25 kg tub at 1.5 mm grain) and drops to ≥ 1.9 kg/m² by machine (approximately 13.2 m² per tub), making it efficient across projects of every scale. Classified to EN 15824:2017 with vapour permeability V2, water absorption W2, and adhesion ≥ 0.35 MPa (DoP 280/CPR), the render sits within the Atlas ETICS system covered by BBA Agrément Certificate 13/5018 — giving architects and contractors a complete, independently certified build-up from adhesive to finish coat.

Key Benefits

• Maximum Pigment Brightness: The white base provides the lightest possible starting point for tinting, which means pastel, cream, off-white, and light neutral shades achieve the truest, most vibrant colour expression — exactly what homeowners and designers look for on prominent front elevations.
• Crack-Free Flexibility: 3D-Flex technology uses a high concentration of polymer resins and cellulose fibres to bridge thermal stress, so the facade absorbs freeze-thaw cycles and rapid temperature swings without micro-cracking — the practical result is a render coat that stays intact through every UK winter.
• UV-Stable White Finish: Mirror Effect high-reflectance additives protect both white pigments and polymer resins against UV degradation, so the surface resists yellowing and chalking far longer than conventional white renders — your facade retains its clean, bright appearance year after year.
• Built-In Biological Defence: Biosec capsule technology releases active agents gradually over the lifetime of the coat, preventing algae and mould colonisation even on north-facing or shaded elevations — a white surface shows every mark, so Biosec's continuous biological defence is especially valuable — it keeps the facade looking freshly rendered without manual cleaning.
• Self-Cleaning Hydrophobic Surface: A dense siloxane layer (the same water-repelling polymer that gives the render its self-cleaning ability) creates a tight surface structure that repels airborne dirt and allows rainwater to rinse particles away naturally, reducing maintenance to a simple soft-wash every few years.
• Faster, Cleaner Application: The 4K aggregate formula bonds readily to the trowel or machine nozzle, cuts product waste on-site, and textures quickly — saving time on large elevations while delivering a consistent lambskin finish (the soft, evenly textured surface that is the standard for modern rendered facades).

Technical Specifications

Property	Value
Pack Size	25 kg plastic bucket
Base Material	Siloxane-enhanced resins with 4K mineral aggregates, cellulose fibres
Grain Size	1.5 mm (lambskin texture)
Base Colour	White — tintable to 406 SAH colours
Density	≈ 1.9 g/cm³
Coverage (hand)	≥ 2.3 kg/m² — approx. 10.9 m² per 25 kg tub
Coverage (machine)	≥ 1.9 kg/m² — approx. 13.2 m² per 25 kg tub
Vapour Diffusion Resistance	0.14 ≤ Sd < 1.4 m
Vapour Permeability Class	V2 (EN 15824)
Water Absorption Class	W2 (EN 15824)
Adhesion	≥ 0.35 MPa
Application Temperature	+5 °C to +30 °C (0 °C with Atlas Eskimo accelerator)
Drying Time (touch)	≈ 15 min at 20 °C / 50 % RH
Full Cure	≈ 24 h at 20 °C / 50 % RH
pH	8
Shelf Life	12 months from date of manufacture
Compliance	EN 15824:2017 (current as of March 2026) · DoP 280/CPR · UKCA · BBA System 13/5018

Application & Compatibility

Gemini RS White performs best when applied as the decorative finish within a certified ETICS build-up (the layered external insulation and render system used across Europe), bonding to a cured quartz primer coat over a properly reinforced basecoat and Atlas 150 g/m² fibreglass mesh. The render adheres to all stable mineral substrates — concrete, traditional cement-lime plasters, and fibre-cement boards — provided the surface is clean, dry, and structurally sound.

• Priming requirement: Apply a system-matched quartz primer from the exterior render primers range at least 24 hours before rendering to regulate substrate suction and create the mechanical key the siloxane resins need for lasting adhesion.
• Machine compatibility: The 1.5 mm 4K aggregate is optimised for professional rendering units (Wagner PC 830, Graco RTX 5500 PX, Graco Fast Finish) with a 6 mm nozzle, delivering a uniform coat at lower material consumption than hand application.
• Low-temperature work: When site temperatures drop below +5 °C, adding Atlas Eskimo Setting Accelerator 0.25 kg extends the working window down to 0 °C and up to approximately 80 % relative humidity, keeping winter projects on schedule.
• White-base colour guidance: The white base achieves the brightest results on light, pastel, and neutral SAH shades — creams, warm greys, soft terracottas, and pure whites all render with maximum clarity. For darker or very intense colours, your installer can specify the appropriate system-matched reinforcing layer to ensure full compatibility, or consider the grey base variant for deeper pigment saturation from the first coat.

Installation Notes

For the cleanest, most uniform white finish, plan each elevation as a single continuous wet-edge pass — the 4K formula gives extended open time, so a two-person crew can cover a full storey before the leading edge sets. Stir the bucket thoroughly with a low-speed mechanical mixer before use (do not dilute or combine with other materials), and use tubs from the same production batch on a single elevation to avoid any shade variation in the white base. For the smoothest result, texture with a plastic float in consistent circular motions rather than alternating directions, which can create visible pattern breaks on a white surface where uniformity is especially critical. Protect freshly applied panels from direct intense sunlight during the first 24 hours of curing — temporary shade mesh helps the render cure evenly, preventing any surface tension. Checking a 48-hour weather window before you start ensures rain stays clear of the fresh coat during its cure, giving you a flawless surface every time.

Trade Insight — Installer's Note

I always reach for the white base Gemini RS on residential front elevations and feature walls where the client wants a pure white or a very light shade — no grey undertone means the final colour reads exactly as the SAH chart shows, and that means you deliver exactly the shade the client signed off on — no return visits to adjust colour expectations. On a recent 80 m² residential front, I hand-applied the white base at about 2.3 kg/m² and the Mirror Effect technology made a noticeable difference: the surface dried uniformly even on a warm day with intermittent sun. For anyone pricing, budget at 2.3 kg/m² hand or 2.0 kg/m² machine, add 10 % for reveals and detailing (roughly one extra tub per 100 m²), and you will hit your material targets comfortably.

Is This Product Right for Your Project?

• Yes — for bright, light-coloured premium facades: Gemini RS White is the right render when your design calls for pure white, soft pastels, or light neutral tones on a facade that demands certified ETICS system compatibility, long-term self-cleaning performance, and biological protection — ideal for residential front elevations, feature walls, and any project where colour brightness and accuracy are the priority.
• Need a grey base for darker shades? The Atlas Gemini RS Grey 25 kg in the same premium range uses identical 4K, Mirror Effect, and Biosec technologies with a grey base — choose it when your colour scheme calls for deep blues, charcoals, or intense terracottas where a grey undertone provides richer pigment saturation from the first coat.
• Looking for a cost-effective alternative? For standard residential elevations with moderate exposure, the broader silicone render collection includes options that deliver excellent hydrophobic and vapour-permeable performance at a lower price point — a smart choice for sheltered facades where the premium 4K, Mirror Effect, and Biosec technologies are not essential.

Frequently Asked Questions

How many tubs of Gemini RS White do I need for my project?

At the standard 1.5 mm grain, hand application uses at least 2.3 kg/m², which means one 25 kg tub covers approximately 10.9 m². For a typical 100 m² elevation, order 10 tubs plus one spare to cover window reveals and detailing. Machine application is more economical — around 1.9 kg/m², giving approximately 13.2 m² per tub — so 8 tubs plus one spare should suffice for the same area.

Will the white finish yellow over time?

Mirror Effect technology is specifically designed to prevent the UV degradation that causes yellowing and chalking in conventional white renders. The high-reflectance additives lower the surface temperature of the white coat and protect the polymer resins and pigments, so the finish retains its original brightness for years. Combined with the self-cleaning hydrophobic surface that rinses away atmospheric deposits during rainfall, a Gemini RS white facade stays visibly brighter for longer than standard alternatives.

When should I choose white base over grey base?

The white base is the right starting point whenever your chosen SAH shade is light, pastel, or neutral — including pure white, creams, soft greys, and muted earth tones. The white starting point provides maximum pigment brightness, so the finished colour on the wall matches the shade chart as closely as possible. For mid-to-dark or very intense colours, the grey base provides deeper pigment saturation and a richer first-coat result — both variants share identical 4K, Mirror Effect, and Biosec technology, so the choice comes down to your final colour palette.

Can I apply Gemini RS White by machine?

The 1.5 mm 4K aggregate is optimised for machine application using professional rendering units (Wagner PC 830, Graco RTX 5500 PX, Graco Fast Finish) with a 6 mm nozzle. Machine application reduces coverage to approximately 1.9 kg/m², giving around 13.2 m² per tub — noticeably more efficient than hand application on elevations above 50 m². The machine-applied texture differs slightly from hand-applied (less aggregate compression), so avoid mixing methods on a single elevation to keep the finish uniform.

Is Gemini RS White an environmentally responsible choice?

Like all Gemini RS variants, the white base is a water-based formulation with low volatile organic compound (VOC) content, which means it releases minimal emissions during application and curing — safer for installers and occupants nearby. Atlas confirms the product's environmental credentials through a Type III Environmental Product Declaration (EPD), independently verified to quantify lifecycle impacts. Combined with a service life measured in decades (the BBA system expects at least 30 years of effective performance), each application cycle replaces what would otherwise be multiple repaint or re-render operations — reducing total material consumption and waste over the life of the building.

Does the BBA certification cover the white variant specifically?

BBA Agrément Certificate 13/5018 covers the complete Atlas ETICS system — adhesive, reinforcing layer, primer, and finish coat assessed together as a single certified assembly. The certificate applies to Atlas Silicone Render within the approved system; Gemini RS is the premium variant of that silicone render line. Using system-matched components (quartz primer, Atlas mesh, and the correct basecoat mortar) ensures the certification and any associated warranty remain valid, and it gives Building Control a clear compliance pathway for sign-off.