Ceresit CT74 Silicone Render White 1.5mm

The CT 74 data sheet is worth reading twice, because it declares two vapour figures for two different things. The product's own EN 15824 line is V1 at Sd 0.14 m; the Sd ≤ 1.0 m beside it is an ETAG 004 figure for a system. Renders World lists the 25 kg tub at £65.00, fetched August 2026.

Where CT 74 Self-Cleaning Silicone Render Earns Its Place on a UK Wall

Ceresit CT74 silicone render white 1.5mm is a ready-mixed thin-layer facade render declared to EN 15824, applied at 2.1 to 2.5 kg/m² over a primed reinforced basecoat as the visible coat of a Ceretherm ETICS build-up. It sits in the Renders World silicone render range as the self-cleaning option, and the sheet is specific about where that finish belongs.

The recommended use is as a facade render within Ceresit Ceretherm ETICS over EPS boards and mineral wool, and on concrete, traditional renders and reinforced mortar layers. Everything else the sheet lists — gypsum, chipboard, gypsum-fibre board, plasterboard and sound existing paint coats — is marked indoor only, which is the line most listings quietly drop.

• External, primed with CT 16: cement and lime-cement renders over 28 days old and concrete over 3 months old, both at 4% moisture or below.
• Reinforced layers: CT 80, CT 85, CT 190 and ZU mortars over 3 days old, or CT 87 over 2 days, each primed with CT 16.
• Dark shades, by the sheet: for intense dark colours, facade application is limited to small areas such as architectural details, so a deep tone is planned as a feature panel rather than a full elevation. The reasoning is set out in the guide to dark render colours and solar exposure.

The Binder Question — What the Sheet Actually Says About the Resin

CT 74 is described in its own technical data as a water dispersion of silicone and acrylic resins with mineral fillers and pigments. That matters commercially: this is a hybrid dispersion, not a single-resin silicone, and any comparison built on a clean silicone-against-acrylic split misreads it from the first line.

What the sheet does claim for the surface is Double Dry Technology — high vapour permeability combined with very low water absorption and high dirt resistance — plus the BioProtect formula against fungi, mould and algae, with total resistance to mould overgrowth recorded in the technical data. The practical consequence is a facade that sheds atmospheric soiling with rainfall on exposed and shaded elevations alike.

• V1 at Sd 0.14 m under EN 15824, the highest permeability class in that standard, so a retrofitted solid wall keeps an outward drying path through the finish coat.
• W3, w ≤ 0.1 kg/m²h⁰·⁵, low absorption declared alongside that permeability rather than traded against it.
• 0.6 MPa adhesion to EN 15824, against ≥ 0.08 MPa for inter-layer adhesion after ageing in the ETAG 004 system test.
• Colour stability and durability are listed as characteristics; how the two binder families genuinely differ is covered in the comparison of silicone and acrylic renders.

Declared Data, Read Row by Row from the CT 74 Sheet

Every value below comes from the Ceresit CT 74 data sheet fetched for this page, with the scope that governs its use. The EN 15824 rows describe the render; the ETAG 004 rows describe a system containing it.

Property	Declared value	Scope
Base	Water dispersion of silicone and acrylic resins, mineral fillers and pigments	Product
Density	1.7 kg/dm³	Product
Consumption, 1.5 mm grain	2.1 to 2.5 kg/m²	Product, 1.5 mm only
Water vapour permeability	Cat. V1, Sd 0.14 m — EN 15824	Product
Water absorption	Cat. W3, w ≤ 0.1 kg/m²h⁰·⁵ — EN 15824	Product
Adhesion	0.6 MPa — EN 15824	Product
Thermal conductivity	≤ 0.61 W/(m·K) — EN 15824	Product
Application temperature	+5 °C to +25 °C, humidity below 80%	Product
Open time	Approx. 15 min	Product
Resistance to rain	24 to 48 hours, depending on temperature	Product
Shelf life	Up to 12 months from the production date, dry and frost-free	Product
Impact resistance	Cat. I or II — ETAG 004, depends on system	System
Water vapour permeability	Sd ≤ 1.0 m — ETAG 004	System
Declaration of Performance	No. 00264, EN 15824	Product

 

One point of housekeeping that a specifier will be asked for: DoP 00264 is the render's own declaration against EN 15824. The nine Ceretherm systems on the sheet each carry their own ETA and their own DoP number, so a system declaration is quoted from the assembly on the drawing, not from this one.

Fire Classification Belongs to the Ceretherm Assembly, Not the Tub

Reaction to fire is declared against named systems, and the class changes with the assembly. The least permissive is given first, and no class here describes the bucket on its own.

• B-s2,d0 in Ceresit Ceretherm Impactum and Universal XPS.
• B-s1,d0 in Universal EPS, Ceretherm Popular, Classic, Premium, Wool Classic and Wool Premium — including the two wool systems, which is why "mineral wool means A2" does not hold.
• A2-s1,d0 in Ceresit Ceretherm Universal MW alone.

The sheet also lists BBA Certificate No. 14/5142 and Irish Agrément Board Certificate No. 09/0340 as documents of reference. Those are pointers to system documentation; until the certificate itself is in hand, the honest statement is that it exists and is referenced, not that this product is certified by it.

Priming Gates, Mixing and Holding the Wet Edge

Application is straightforward once the substrate clears its age and moisture gates, and the sheet sets the priming trigger by condition rather than by the clock. Get the primer and the crew size right and the finish looks after itself.

Priming and Preparation

• CT 16 priming paint is the specified coat, tinted close to the render colour; take it from the Renders World exterior render primers range.
• Absorbent substrates get CT 17 first, then CT 16 after a minimum of two hours.
• Render only when CT 16 is completely dry — dryness is the gate the sheet names, with no hour figure attached to it.
• Reinforce the basecoat with 150 g/m² Atlas mesh before priming; the full sequence sits in the primer selection guide for thin-coat renders.

Mixing, Floating and the Batch Number Nobody Checks

Stir the whole container, adding no more than 1% clean water if the consistency needs it, and keep rusty tools and containers away from the material. Apply at grain thickness with a steel float held at an angle, texture with a plastic float held flat in circular movements, and never sprinkle the surface with water.

• One production batch per elevation: the sheet asks for a single batch number, printed on each container, across one surface — mineral fillers vary enough between batches to show. Checking the lids before the scaffold goes up is a two-minute job that protects the whole wall.
• Staff the lifts: with a 15-minute open time, enough operatives across the scaffold levels to work wet on wet is what produces an even texture.
• Plan the stop: tape the line before pausing and restart from the taped edge.
• Keep off sunlit walls and protect from rain until dry; rain resistance arrives between 24 and 48 hours depending on temperature, so a cool week needs the longer window. Seasonal planning is covered in the guide to render application timing across the UK year, and the trowel method in the step-by-step thin-coat guide.

Ordering CT 74 — Tub Price, Coverage Spread and What the Spread Costs

The consumption figure is a range rather than a point, and on a large elevation that range is worth money. Both ends are shown so a quantity can be checked against a real wall.

• Tub: £65.00 per 25 kg container, fetched August 2026.
• Coverage: 25 kg ÷ 2.5 kg/m² = 10 m²; 25 kg ÷ 2.1 kg/m² = 11.9 m². One tub covers 10 to 11.9 m².
• Per square metre: £65.00 ÷ 10 m² = £6.50/m² at the heavy end; £65.00 ÷ 11.9 m² = £5.46/m² at the light end.
• A 100 m² elevation: 100 ÷ 10–11.9 = 8.4 to 10 tubs, plus 10% for reveals and waste = 9 to 11 tubs.

Those are render-coat materials only — no primer, basecoat, mesh, beads or labour, and no installed rate, since labour is not a figure this store publishes. Build the full list with the render coverage calculator. Renders World dispatches parcels next day and pallets next day or on a two-business-day economy service, kerbside, from Southampton.

CT 74 Beside the CT 174 Renders — Where the Sheets Diverge

All three sheets were read together, and the surprise is how much they share: the same V1 class at Sd 0.14 m for both 1.5 mm renders, the same 0.6 MPa adhesion, the same thermal conductivity and the same 15-minute open time. The differences that survive are the ones worth specifying on.

Render	Consumption and density	What separates it
CT 74, 1.5 mm (this tub)	2.1–2.5 kg/m², 1.7 kg/dm³	Self-clean and BioProtect claims; rain resistance 24–48 h
CT 174, 1.5 mm	Approx. 2.5 kg/m², 1.8 kg/dm³	Silicate-silicone binder; rain resistance approx. 24 h
CT 174 Machine, 1.0 mm	Approx. 1.5 kg/m², 1.9 kg/dm³	Cat. V2, 0.14 ≤ Sd ≤ 1.4 m; works to +30 °C

 

Read commercially, the lighter end of the CT 74 range is the cheapest square metre of the three at 1.5 mm grain, and the machine grade is cheaper still on material but sits a full vapour class lower. Where breathability is the reason for the specification, that V1 against V2 step is the line that decides it. Brand-level differences are set out in the Atlas and Ceresit silicone render comparison.

Specifying CT 74 With Confidence

• Choose it where self-cleaning and biological resistance are the point — urban, coastal and shaded elevations — with V1 permeability at Sd 0.14 m and W3 absorption declared together.
• Confirm the assembly before quoting a fire class: the class follows the Ceretherm system, and Universal MW is the only one carrying A2-s1,d0.
• Order the shade physically first: the sheet declares the full Ceresit Colours of Nature palette without stating a count, so the render colour charts and sample books are the reliable reference, and dark tones stay within the small-area restriction.
• Plan the refresh, not the replacement: the sheet names Ceresit CT 48 and CT 49 silicone paint as the renovation route over cured CT 74, which keeps the render in service; general upkeep is covered in the silicone render maintenance guide. Renders World holds this 1.5 mm white grade in 25 kg tubs for next-day dispatch.

FAQ — Quantities, Substrates, Fire and Renovation

How many tubs cover a 60 m² elevation?

Six to seven. At 2.1–2.5 kg/m² one 25 kg tub does 10–11.9 m², so 60 m² needs 5.1 to 6 tubs bare, and a 10% allowance for reveals and detailing takes it to 6–7 from one batch.

Can CT 74 go straight onto plasterboard or an old painted wall?

Only indoors. The sheet restricts gypsum, chipboard, gypsum-fibre board, plasterboard and sound paint coats to interior use; outside, the substrate is cement or lime-cement render, concrete or a reinforced mortar layer, primed with CT 16.

Which fire class applies to a CT 74 facade?

Whichever the system carries: B-s2,d0 in Impactum and Universal XPS, B-s1,d0 in Universal EPS and the Popular, Classic, Premium, Wool Classic and Wool Premium systems, and A2-s1,d0 in Universal MW. The render alone holds none of them.

Is it suitable for spray application?

Yes — the sheet confirms machine application and names Wagner PC 15, PC 830 and SPG Baumaschinen PG 20, at the same 2.1–2.5 kg/m² consumption as hand work.

How is an aged CT 74 facade brought back?

By overpainting with Ceresit CT 48 or CT 49 silicone paint, the route the sheet names, which restores the surface without stripping the existing render back.

Technical Documentation — CT 74 Data Sheet

• Technical Data Sheet — Ceresit CT 74 Silicone Self Clean (PDF)