Choosing silicone render colours is a decision the reinforcing layer underneath partly makes for you. Every figure here comes from three Atlas data sheets and one Ceresit sheet read this session, and the finding that reorders the whole exercise is this: the two Atlas renders Renders World stocks declare different palette sizes and different dark-shade rules, so the shade and the adhesive are one specification rather than two. Physical references for both sit in the render colour charts range.
How Light Reflectance Decides Which Silicone Render Colours You Can Specify
Choosing silicone render colours on an insulated wall turns on one declared number — light reflectance, written HBW — because the Atlas Silicone Render sheet dated March 2022 permits shades above 6% HBW only over a reinforced layer of a named dispersion adhesive. Below that value the sheet offers no route at all, which makes reflectance the first thing to establish and the adhesive the second.
The thresholds are not one manufacturer rule but three, and they differ by product. Reading them side by side is the single most useful thing a specifier can do before a shade is approved, because the same charcoal may be straightforward on one render and unavailable on another.
| Render | Reflectance threshold | Reinforced layer the sheet requires |
|---|---|---|
| Atlas Silicone Render | HBW above 6% | ATLAS STOPTER K-100 dispersion adhesive compound |
| Atlas Silicone Render | HBW above 15% | ATLAS HOTER U2 or HOTER U2 WHITE universal gel mortar |
| Atlas Gemini RS | HBW above 15 | STOPTER K-50, STOPTER K-20, or GRAWIS U at minimum 5 mm with double ATLAS 150 mesh |
| Atlas Gemini RS | No HBW limit | Permitted on a maximum of 10% of the elevation |
| Ceresit CT 76 Solar Protect | HBW at or above 15 | Consult Ceresit technical department below 15 to select the insulation system |
That last Gemini row is the most useful line on either Atlas sheet for anyone planning a two-tone facade. An intense shade with no reflectance restriction at all is permitted on up to a tenth of the elevation, which is precisely how a deep accent band, a plinth or a recessed entrance panel gets specified without reworking the adhesive across the whole building. Design the strong colour as a minority area and the constraint stops being one.
One naming point to settle at order stage: the Atlas sheet writes the second mortar as HOTER U2 or HOTER U2 WHITE in its properties section and as HOTER U2-B in its substrate table, so confirm the exact product code with us rather than assuming the three names are interchangeable stock.
Why Two Atlas Renders Declare Different Palettes
Both sheets name the same SAH colour scheme, and both declare a different number of colours in it. Atlas Silicone Render declares 480 colours to the SAH Paints and Plasters range, with individual colour selection to customer instruction available on top. Atlas Gemini RS declares 406 SAH colours. The Atlas Salta facade paint sheet read alongside them declares 406 SAH colours including six whites.
That divergence is a purchasing instruction rather than a curiosity. Where render and paint must agree on one building — a new elevation beside a repainted one, or a phased scheme — 406 is the working figure, because a code that exists in the 480-colour render range may not exist in the 406-colour paint range. Where the whole job is Atlas Silicone Render, the full 480 is available. Confirm the code against the product being ordered, never against the scheme name.
Key Takeaway: Fix three things together before a shade is signed off — the reflectance value, the reinforcing adhesive the sheet ties it to, and the product the code is being confirmed against. A colour approved without its adhesive is an approval that may not survive the order.
What the Sheets Say About Shade Uniformity on the Wall
Three separate mechanisms in these documents make one approved colour read as two on a finished facade, and all three are controllable at ordering and programming stage. This is where a colour decision succeeds or disappoints, more than in the choice of tone itself.
- Application method changes the colour. Both Atlas sheets state that hand-applied and machine-applied render have different textures, which may produce slight colour differences depending on how developed the surface is — and both then rule that combining the two technologies on one building is not permissible. Decide hand or machine before the shade, not after.
- Production date changes the colour. All three Atlas sheets and the Ceresit CT 76 sheet instruct that one surface receives material of the same production date, CT 76 specifying the same batch number printed on each container, because its mineral fillers can themselves cause colour variation. Order the full quantity for an elevation in one go.
- Break placement changes the colour. The Atlas sheets require the wet-on-wet method, with breaks planned in advance at corners, building folds, under downpipes and at colour junctions. On a two-tone scheme the tonal boundary and the technological break want to be the same line.
CT 76 adds one further instruction worth knowing before a colour is chosen for a bright wall: the render should not be applied on highly sunny walls and needs protecting from too-fast drying, with scaffolding protection recommended. That is an application constraint on the product rather than a property of the shade, and it applies whatever colour is in the bucket.
How Grain and Texture Change a Shade You Have Already Approved
Texture is declared, so it can be specified rather than guessed. Atlas Silicone Render comes in lambskin textured aggregate to 1.5 mm as N-15 and 2.0 mm as N-20, and only the N-15 version can be machine-applied. Gemini RS is declared as lambskin at up to 1.5 mm only. Ceresit CT 76 offers 1.5 mm or 2.0 mm in a stone-like structure.
Because aggregate depth governs how much shadow sits between grains, a swatch is only informative when its grain matches what the job will buy — so ask which version any physical reference was made at. The quantity consequence is declared too, and it is substantial: Atlas Silicone Render consumes from 2.2 kg/m² by hand at up to 1.5 mm against from 2.8 kg/m² by hand at up to 2.0 mm, a step of 0.6 kg/m², or roughly 27% more material for the coarser texture on the same wall. Gemini RS consumes from 2.3 kg/m² by hand and from 1.9 kg/m² mechanically. Both sheets note that exact consumption is established by a trial on the substrate itself.
How to Work a Shortlist Down to One Code
The Atlas sheets tie colour fastness to their pigment technology — hybrid mixtures of inorganic and organic pigments with reflective additives, confirmed by Xenotests on the Silicone Render sheet — which is the reason a physical rendered swatch stays representative long enough to be worth ordering. Neither sheet states a service life in years, so none is quoted here.
- Establish the elevation's exposure and the reinforcing layer already specified. If the adhesive is fixed, the reflectance floor is fixed with it, and the shortlist narrows before anyone opens a chart.
- Order the reference that matches the brand you will buy. The Atlas 480-colour catalogue and the 24-shade Atlas sample set both read £10.00 at the Renders World product endpoints in August 2026, no VAT figure displayed, so the full catalogue costs no more than the curated set — the smaller set earns its place as a handling tool for first conversations, not as the cheaper option.
- Assess outdoors, against the actual wall, at more than one hour of the day. The sheets' own point about surface development explains why: how a pigment reads depends on how light meets the texture.
- Check the code exists in the product you are ordering — 480 for Atlas Silicone Render, 406 for Gemini RS and Salta paint.
- Record the code at sign-off. It travels to the tub label and settles any question at handover.
Two constraints sit outside the data sheets. For a wall in a conservation area, National Park, Area of Outstanding Natural Beauty or the Broads, Planning Portal guidance on external walls states that planning permission must be applied for before cladding a house with render, and that listed buildings need listed building consent for significant works — so the palette conversation may follow a planning conversation rather than precede it. And on renovation, the Atlas Silicone Render sheet names ATLAS SALTA N as its repainting route while Gemini RS names ATLAS SALTA, SALTA N or SALTA N PLUS; the bucket stocked in the Renders World silicone masonry paints range is ATLAS SALTA, so confirm the variant before planning a matched repaint years out.
Turning an Approved Shade Into an Order
A colour decision made this way arrives at the order with everything attached to it: a code, the product that code belongs to, a reflectance value, and the reinforcing adhesive the sheet ties that value to. Order the reference first, assess it on the wall, then match the approved code to a system from the Renders World silicone render range — where the deep-shade routes described above are stocked alongside the renders themselves. Where the scheme is heading towards earth tones or a single drenched elevation, the 2026 earth-tone and colour-drenching guide works through those compositions, and the dark shades and solar exposure guide owns the reflectance question in depth for south and west walls.
Written by Mariusz Saja. Technically reviewed by Renders World Team. Last reviewed Aug 2026.
Choosing Render Colours — Your Questions Answered
Can I specify a very dark shade on an insulated wall?
Yes, with the reinforcing layer doing the work. Atlas Silicone Render permits shades above 6% HBW over a STOPTER K-100 reinforced layer and above 15% over HOTER U2 or HOTER U2 WHITE. Gemini RS permits above 15 HBW over STOPTER K-50, STOPTER K-20 or GRAWIS U at minimum 5 mm with double ATLAS 150 mesh, and permits intense shades with no reflectance limit on up to 10% of the elevation. Confirm the reflectance value of your chosen code with us, since the sheets state the thresholds but not the value of each shade.
How many colour references does one project need?
One per brand is normally enough, plus a decorative reference where a plinth or feature finish is in the scheme. Since the 480-catalogue and the 24-shade set are the same £10.00, the catalogue is the better first order whenever a code has been issued or an existing facade is being matched.
Does an Atlas SAH code transfer between products?
Within Atlas it does, with a caveat worth catching early: Atlas Silicone Render declares 480 SAH colours while Gemini RS and Salta paint each declare 406, so a code chosen from the widest palette is confirmed against the narrower one before a matched render-and-paint order is placed. A Ceresit product uses its own numbering, and an SAH code does not carry across to it.
Does grain size change how the colour looks?
It changes how light meets the surface, so the same pigment reads differently at 1.5 mm and 2.0 mm. Atlas Silicone Render is declared in both, as N-15 and N-20, and Gemini RS at up to 1.5 mm only. It also changes quantity: from 2.2 kg/m² by hand at up to 1.5 mm against from 2.8 kg/m² at up to 2.0 mm. Ask which version any swatch was produced at before judging a shade from it.
What keeps one colour reading evenly across a whole elevation?
Three things the sheets are explicit about: material of one production date on one surface, a single application technology across the building since hand and machine textures differ and cannot be combined, and technological breaks planned in advance at corners, folds, downpipes and colour junctions using the wet-on-wet method.
Do I need permission before changing a render colour?
Planning Portal guidance states that repairs, maintenance and minor improvements such as painting a house need no application, but that in a conservation area, National Park, Area of Outstanding Natural Beauty or the Broads, planning permission must be applied for before cladding a house with render. Listed buildings need listed building consent for significant works. Your local planning authority is the place to confirm what applies to your address.
Can the colour be changed later?
Both Atlas renders name a repainting route for renovation, which is the practical answer to a shade that no longer suits. The Silicone Render sheet names ATLAS SALTA N, and Gemini RS names ATLAS SALTA, SALTA N or SALTA N PLUS. Since the palette declared for the paint is 406 SAH colours against 480 for that render, check the target code exists in the paint range before committing to a matched recoat.