Description
Ceresit CT76 Solar Protect render 25kg is the colour-stability choice in the Renders World silicone range. What separates it from its neighbours is neither dirt resistance nor reflected warmth: it is a raised ultraviolet absorber content, a surface that closes its own microcracks, and a reflectance floor a specifier checks before a shade is signed off.
What Ceresit CT76 Solar Protect Render 25kg Is Built to Resist
Ceresit CT76 Solar Protect render 25kg is a silico-elastomeric thin-layer facade render declared to EN 15824 and supplied in 1.5 mm and 2.0 mm grain. It sits in the silicone render range as the specification for elevations where the colour has to survive the sun.
Ultraviolet light destroys polymer bonds at the surface, and that is what produces chalking and a washed-out tone after a few seasons. CT 76 answers it in two ways the manufacturer states plainly: an increased quantity of UV absorbers, which is where the colour light fastness comes from, and special additives and fillers that give the surface an ability to “self-heal” microcracks — the quotation marks are the manufacturer's own.
- Inside an ETICS build-up over EPS boards or mineral wool. That is the primary use named for it.
- On concrete, traditional renders and reinforced mortar layers, where no insulation is involved.
- Indoors only: gypsum below 1% moisture, chipboard, gypsum-fibre board, plasterboard and sound paint coats. Every one of those is an interior substrate and none of them is an external option.
- Where growth and surface dirt are part of the brief. Alongside the UV claims, the declaration lists self-cleaning and protection against fungus, mould and algae.
The HBW Figure and What It Asks of a Specifier
This is the number that decides whether CT 76 belongs on a scheme, and it is stated as a recommendation with a direction of travel. For facade durability, and to prevent excessive heating of the facade surface, Ceresit recommends CT 76 with a light reflection value of HBW 15 or above. Below that figure it asks for the solution to be discussed with its technical department so an appropriate insulation system is chosen.
Taken as written, that is a floor rather than a licence. The render is not positioned as a way of making very dark shades safe: the reflectance minimum stays in place, anything under it is routed back to the manufacturer, and the question is framed as insulation system selection, not finish selection. A scheme sitting near or below the threshold is a conversation before it is an order.
- HBW 15 and above: inside the recommendation, no further step.
- Below HBW 15: a documented consultation with the manufacturer's technical department, aimed at the insulation system, not at the finish.
- Palette: Colours of Nature and Intense are both listed as available. That is a range statement and it is separate from the reflectance recommendation above.
Declared Data and the Scope That Governs Each Figure
The declaration separates two families of value, and mixing them is the commonest error in published render comparisons. First comes the render itself, tested to EN 15824.
| Property | Declared value | Scope |
|---|---|---|
| Base and binder | Silicone and acrylic resin dispersion | Product |
| Density | 1.7 kg/dm³ | Product |
| Consumption, 1.5 mm grain | 2.1 to 2.5 kg/m² | Product |
| Consumption, 2.0 mm grain | 3.1 to 3.4 kg/m² | Product |
| Water vapour permeability | V1 — EN 15824 | Product |
| Water absorption | W3 — EN 15824 | Product |
| Adhesion | 0.6 MPa — EN 15824 | Product |
| Thermal conductivity | 0.61 W/(m·K) or below | Product |
| Application temperature | +5 °C to +25 °C | Product |
| Humidity during application | Below 80% | Product |
| Drying time | Approx. 15 min | Product |
| Resistance to rain | 24 to 48 hours | Product |
| Resistance to mould overgrowth | Total resistance | Product |
| Storage | Up to 18 months from production | Product |
ETAG 004 values are a different animal. They are declared for a system containing CT 76, not for the tub, and they move with the build-up, not with the finish. A specification that quotes an ETAG figure as a product figure has silently promoted a system property onto a product, and that single move has inverted the vapour performance of this render in more than one published comparison.
| Property | Declared value | Scope |
|---|---|---|
| Impact resistance | Cat. II — ETAG 004 | System |
| Water vapour permeability | Sd 1.0 m or below — ETAG 004 | System |
| Water absorption after 24 h | Below 0.5 kg/m² — ETAG 004 | System |
| Inter-layer adhesion after ageing | 0.08 MPa or above — ETAG 004 | System |
Fire Classification Follows the Ceretherm System
Reaction to fire is declared against named assemblies, so the class comes off the drawing, not off the tub. The less permissive class is listed first.
- B-s1,d0 in Ceretherm Popular, Classic, Wool Classic and Universal EPS. Wool Classic is in that list, so a mineral wool build-up does not automatically carry the higher class.
- A2-s1,d0 in Ceretherm Universal MW alone.
- European Technical Assessments are printed for the named Ceretherm systems, each with its own CPR certificate and Declaration of Performance number. Every one of them belongs to an assembly, and none belongs to the render.
What the Declaration Does Not Contain
On a product sold on sunlight, absence carries as much weight as presence. Three absences are worth naming, because each one is a claim somebody else has made for this render.
- No infrared or heat reflection figure. There is no surface temperature reduction and no percentage of solar gain anywhere in the technical data, so a specification written around reflected heat is written around something the manufacturer does not declare. What the document does answer is ultraviolet exposure and colour stability.
- No Declaration of Performance number for the render itself. The DoP numbers printed belong to the Ceretherm systems, and a system number is not a product number.
- No mesh, in any grade. Reinforcement is specified by the Ceretherm system chosen, not by the finish, so a mesh weight lifted from another manufacturer's certified system would be somebody else's figure standing on a Ceresit render.
Priming Gates, Mixing and Working the Wall
The method matches the rest of the thin-coat family, and the priming trigger is a condition rather than a stated number of hours. Get the substrate gates right and the finish behaves predictably.
Substrate Gates and Priming
- Cement and lime-cement renders over 28 days old.
- Concrete over 3 months old, at 4% moisture or below.
- Reinforced layers of CT 80, CT 85, CT 190, ZU or Thermo Universal, over 3 days old.
- All three take CT 16 priming paint. An absorbent substrate takes CT 17 first, then CT 16 after a minimum of two hours, and rendering waits until CT 16 is completely dry — that is the gate named, with no hour figure attached to it. Tint the primer close to the render colour; CT 16 sits in the exterior render primers range.
- Uneven and damaged substrates are smoothed first, with CT 29 filler named for traditional renders and concrete. Elastic, lime and adhesive paint coats come off; they are not overcoated, and the full sequence sits in the substrate preparation guide.
Mixing, Floating and the Batch Number
Stir the whole container and add no more than 1% clean water if it needs it, keeping rusty tools and containers out of the mix. Apply at grain thickness with a steel long float held at an angle, then texture with a plastic float held flat, in circular movements. Never sprinkle the surface with water, and never mix the product with other renders, pigments, resins or binders.
- One batch number per elevation. Mineral fillers cause colour differences between production runs, and the batch number is printed on every container. On a saturated shade that check is the difference between one wall and two.
- Staff the scaffold levels so the work stays wet on wet, and plan any stop with self-adhesive tape: render up to it, form the texture, pull the tape with the render on it, restart from that edge.
- Keep it off highly sunny walls and protect it against drying too fast; scaffolding protection is recommended, and rain protection runs to the 24 to 48 hour mark. Timing across the year is covered in the render application timing guide, and the trowel method in the step-by-step thin-coat guide.
Coverage, Grain and How Many Tubs
Consumption for Ceresit CT76 Solar Protect render 25kg is declared as a range, and on a full elevation the two ends are more than a tub apart. Both ends are worth carrying into the order, because the wall decides which one you get.
- One 25 kg tub at 1.5 mm grain: 25 ÷ 2.5 = 10 m² at the heavy end, 25 ÷ 2.1 = 11.9 m² at the light end.
- A 100 m² elevation at 1.5 mm: 8.4 to 10 tubs bare, and 9 to 11 tubs once a 10% allowance for reveals and detailing goes in.
- Stepping up to 2.0 mm grain moves consumption to 3.1–3.4 kg/m², which is 7.4 to 8.1 m² a tub — roughly a third more material for the same wall, and worth pricing before the texture is agreed.
Those numbers are the render coat alone: no primer, no basecoat, no beads, no labour and no installed rate. Build the full materials list with the render coverage calculator.
CT 76 Beside CT 74 and CT 174 — Where the Declarations Separate
The three Ceresit thin-coat renders on this range share more than the marketing suggests: the same V1 classification, the same W3 absorption, the same 0.6 MPa adhesion and the same thermal conductivity, and all three carry the manufacturer's biological protection against fungus, mould and algae.
Two of them also list self-cleaning. CT 74 carries it in its trade name and CT 76 carries it in its own characteristics, so dirt resistance is common ground, not the line that divides them. What divides them is narrower.
| Render | Consumption at 1.5 mm | What its own declaration adds |
|---|---|---|
| CT 76 Solar Protect (this tub) | 2.1–2.5 kg/m² | UV absorbers, self-healing, HBW 15 floor, 18-month storage |
| CT 74 Silicone Self Clean | 2.1–2.5 kg/m² | Third grain at 2.5 mm, its own DoP 00264, 12-month storage |
| CT 174 Silicate-Silicone | Approx. 2.5 kg/m² | Different binder, rain resistance approx. 24 h, DoP 00269 |
Take CT 76 where colour light fastness over years of sun is what the client will judge — south and west elevations, saturated tones, schemes where fade will be noticed long before dirt is. Take CT 74 where a 2.5 mm grain is wanted, or where a render-specific Declaration of Performance has to be produced for the file. Brand-level differences sit in the Atlas and Ceresit silicone render comparison.
Ordering, Tinting and Returns
Every Ceresit CT76 Solar Protect render 25kg tub leaving Renders World is tinted to the shade on the order, and that changes three practical things about buying it.
- Renders World tints here, while the order is picked. Each manufacturer has its own mixer kept for it, so a Ceresit shade is never mixed on an Atlas machine.
- Prices are not published here because they move. Ask for a current figure against the shade, the grain and the quantity.
- A tinted tub sits outside the 14-day change-of-mind return, because a mixed shade cannot go back into stock. The terms are in the cancellations and returns policy.
- Next-day dispatch is an option, on parcels and on pallets, from Southampton, and a pallet can go instead on a two-business-day economy service. Every delivery is kerbside. Collection is open as well: the counter at Unit 9A, Central Trading Estate in Southampton runs Monday to Friday from 7am to 5pm and Saturday morning until noon, and a tub is tinted to your shade there and then.
Shades are confirmed physically before an order is mixed. Colours of Nature and Intense are both listed as available without a stated count, so the render colour charts and sample books settle a shade, never a screen.
FAQ — Quantities, Reflectance, Substrates and Renovation
How many tubs cover 100 m²?
Nine to eleven at 1.5 mm grain. At 2.1–2.5 kg/m² one 25 kg tub does 10–11.9 m², which is 8.4 to 10 tubs bare, and a 10% allowance for reveals and detailing takes it to 9–11 — all from a single batch number.
Does CT 76 make very dark shades safe on an insulated wall?
Not on its own terms. It is recommended with a light reflection value of HBW 15 or above, and below that figure the documented next step is a consultation with the technical department so an appropriate insulation system can be chosen. A very dark scheme is therefore a manufacturer conversation rather than a straight substitution of finish, and the reflectance and orientation background sits in the guide to dark colours and solar heat on render.
Can it go on plasterboard or an old painted wall?
Indoors only. Gypsum below 1% moisture, chipboard, gypsum-fibre board, plasterboard and sound paint coats are all listed as interior substrates. Outside, it goes on render, on concrete or on a reinforced mortar layer, primed with CT 16.
Which fire class applies to a CT 76 facade?
Whichever the assembly carries, because the render holds no class independently of the system it finishes.
- B-s1,d0 in Ceretherm Popular, Classic, Wool Classic and Universal EPS.
- A2-s1,d0 in Ceretherm Universal MW.
How long can tinted stock be held?
A tinted tub of Ceresit CT76 Solar Protect render 25kg keeps for up to 18 months from the production date, in dry cool conditions and in undamaged packaging, protected from frost and direct sunlight. That is six months longer than the CT 74 and CT 174 declarations allow, which matters to anyone holding mixed shades against a phased programme.
How is an aged CT 76 facade refreshed?
By painting with CT 48 or CT 49 silicone paint, the renovation route named for it, which restores the surface without stripping the existing render. Upkeep between refreshes is covered in the silicone render maintenance guide.
Technical Documentation
The manufacturer's own technical data sheet carries every declared value quoted here, in full: