Description
Spray rendering lives or dies on consistency: one tub mixed differently from the last, or a nozzle running at the wrong pressure, shows up across a whole elevation. Ceresit built this grade for pumps, gave it a stone-like 1.0 mm structure, and set the consumption low enough that a commercial facade is a manageable pallet count.
Where CT 174 Machine Sprays Best on Large UK Elevations
Machine CT174 silicate-silicone render 1.0mm sprays at an assumed 1.5 kg/m² through a 6 mm nozzle, giving spray crews an even, stone-textured finish across large ETICS elevations in one continuous pass. Renders World stocks it in the premium silicone render range as the pump-fed member of the Ceresit thin-coat family.
- Ceretherm ETICS facades — the sheet recommends it as the facade render within Ceresit Ceretherm external thermal insulation composite systems built with EPS boards and mineral wool. Those two board types are what the document names, so those are the two this page claims.
- Cured mineral substrates — concrete over three months old and cement or cement-lime renders over 28 days old, each at 4 % moisture or below, primed with Ceresit CT 16.
- Reinforced basecoats — layers made with Ceresit CT 85, ZU, CT 190 or CT 100 at more than three days old, or CT 87 at more than two days, primed with CT 16 in every case.
- Interior work — the sheet also covers gypsum substrates below 1 % moisture, gypsum-fibre and plasterboard, and sound existing paint coats, all inside the building only.
The pattern behind those substrate rules is a single requirement: a smooth, load-bearing, dry and clean surface, primed so the render meets uniform suction. Get that right and a fine 1.0 mm grain rewards you, because it hides nothing and needs to hide nothing.
Why Spray Contractors Specify the 1.0 mm Grade
- Dedicated to machine application: the sheet lists machine application and optimised consumption as the product's defining characteristics, with a homogenous final structure as the intended result — this is a CT 174 render for machine application rather than a hand render that tolerates a pump.
- Vapour permeable at V2: Sd between 0.14 m and 1.4 m to EN 15824, so moisture keeps moving outward through the finish and the insulation beneath it stays dry through a UK winter.
- Low water absorption at W3: w ≤ 0.1 kg/m²h⁰·⁵ to EN 15824, the class that keeps driving rain sitting on the surface rather than soaking into the coat.
- Adhesion of 0.6 MPa to EN 15824, declared for the render on a prepared and primed substrate — the figure that matters when a fine coat is being asked to hold across a full storey.
- Combined binder behaviour: Ceresit describes the product as combining the good points of a silicate render and a silicone render — vapour permeable, low in absorbability and dirt resistant — from a water dispersion of synthetic resins with mineral and pigment fillers.
Declared Performance From the CT 174 Machine Data Sheet
| Property | Declared value |
|---|---|
| Pack | 25 kg plastic container |
| Grain and structure | 1.0 mm, stone-like |
| Density | 1.9 kg/dm³ |
| Assumed consumption | approx. 1.5 kg/m² |
| Water vapour permeability | cat. V2, 0.14 ≤ Sd ≤ 1.4 m (EN 15824) |
| Water absorption | cat. W3, w ≤ 0.1 kg/m²h⁰·⁵ (EN 15824) |
| Adhesion | 0.6 MPa (EN 15824) |
| Thermal conductivity | λ = 0.61 W/(m·K) (EN 15824) |
| Application temperature | +5 °C to +30 °C, humidity below 80 % |
| Open time | approx. 15 min |
| Resistant to rain | after approx. 24 hours |
| Recommended nozzle | ≥ 6 mm, minimum 2 bar |
| Shelf life | up to 12 months from the production date |
| Standard | complies with EN 15824 |
| Named in ETAs for Ceretherm systems | Popular 08/0309 · Classic 09/0014 · Premium 08/0308 · Wool Premium 09/0037 · Wool Classic 09/0026 |
The consumption line drives the order: 25 kg ÷ 1.5 kg/m² = approximately 16.7 m² per container. Those European Technical Assessments belong to the five Ceretherm systems named beside them, not to the tub on its own, so specify the system and the render together and the reference documents line up.
No price, stock figure or lead time is published on this page. The product endpoint returned a truncated response with no commercial field and the rendered page carries none, so this audit publishes nothing about cost. What is a real site-wide fact: Renders World despatches from Southampton, processes in-stock orders the same day and confirms the delivery method with you after the order is placed.
How to Prime and Spray CT 174 Machine, Step by Step
- Prepare and prime. Smooth and repair uneven or damaged substrates first, remove dirt, weak layers and elastic, lime or adhesive paint coats, then prime with CT 16; absorbent substrates take CT 17 first, with CT 16 following after at least two hours. Choose a CT 16 colour close to the render shade.
- Wait for the primer to dry completely. The sheet's condition is exactly that — the render goes on when the priming paint is fully dry, not on a fixed clock.
- Stir the whole container until uniform, adjusting consistency to your machine with no more than 2 % clean water, then mix again. The product is never combined with other renders, pigments, resins or binders.
- Calibrate on a sample panel — the sheet asks for a test application on something like a plasterboard offcut, to set consistency, flow, nozzle size, delivery rate and pressure before the facade. Minimum recommended pressure is 2 bar, and the right figure shifts with machine type, hose length and pumping height.
- Spray at 40–60 cm, square to the wall, holding the nozzle vertically at 90° and working in smooth passes: two layers in circular motion, or with a gun, one horizontal pass then one vertical, wet on wet.
- Build to grain thickness — roughly 1 mm — for complete, even coverage, keeping delivery rate and pressure under control throughout so the finished structure reads the same across the bay.
The primer comes from the quartz key coats in the exterior render primers range, and the reinforced layer beneath is built with mesh from the alkali-resistant rendering mesh collection — pick the grade that matches the basecoat your system specifies. Trowel technique, panel planning and finishing sequence for thin coats generally are covered in the step-by-step thin coat rendering method.
Machine Setup, Batching and Weather Protection on Site
- Conditions: ambient and substrate between +5 °C and +30 °C with humidity below 80 %. Every figure on the sheet was obtained at +23 °C and 50 % relative humidity, so hardening runs faster or slower as site conditions move away from that.
- Timing: approximately 15 minutes of open time and rain resistance after approximately 24 hours — plan texturing to follow the spray head closely and programme the elevation around the 24-hour figure.
- Sun and rain: the sheet directs that the render is not applied to walls in solar radiation, to avoid drying too fast, and is protected from rain until completely dry; scaffolding sheeting is the recommended protection.
- Batching: mineral fillers can produce colour differences between production runs, so one surface is rendered from containers carrying the same production badge number. Checking the numbers before the first lid comes off is a two-minute job with a very good return.
- Continuity: work one surface without breaks at a constant consistency. Wash the machine, hoses and tools with water immediately; hardened residue has to come off mechanically.
Shoulder-season planning against the +5 °C floor is set out in the guide to render application timing in UK conditions, and the wider trade-off between pump and trowel — crew size, setup time and consumption — is weighed in the machine against hand-applied render comparison.
Choosing Between the 1.0 mm Machine Grade and the 1.5 mm Hand Grade
| Variant | Application method | Where it belongs |
|---|---|---|
| CT 174 MACHINE 1.0 mm | Spray, ≥ 6 mm nozzle at 2 bar minimum | Large elevations run by a calibrated pump crew |
| CT 174 hand-applied 1.5 mm grade | Separate product with its own data sheet | Trowel work and mixed-method projects |
These two share a name and a chemistry family, not a document. The machine sheet declares figures for the machine grade only, and this audit has removed the consumption and vapour class that the previous version of this page quoted for the 1.5 mm variant, because they were taken from the wrong sheet. Ask for the hand grade's own figures when you compare the two, and the comparison stays honest.
Ordering CT 174 Machine for a Commercial Programme
- Specify machine CT174 silicate-silicone render 1.0mm where a calibrated pump, a fine uniform texture and a low consumption rate are the point of the job, and where the build-up is one of the five Ceretherm systems the sheet names.
- Deep and intensive shades: the sheet limits intensive dark colours on this render to small areas such as architectural details. That is a tighter instruction than the Atlas renders in this collection carry, where the manufacturer sets a reflectance threshold and a basecoat condition instead — so for a dark full elevation, choose the range whose sheet supports it and read the guidance on dark render shades and solar exposure before signing off the scheme.
- Colour selection: the product is available across the Ceresit Colours of Nature palette; view the swatches through the render colour charts and sample books rather than a printed chip, and confirm the shade reference on the order.
- Still weighing binders? The silicone render buying criteria compared set out how grain, binder and certification are ranked against project type across the wider thin-coat render collection.
- To order: take your tub count from the consumption figure below, keep the containers in one production batch per elevation, and add the CT 16 primer to the same delivery so nothing waits on site.
FAQ — Quantities, Substrates and Spray Settings
How many containers does a 500 m² facade need?
At the assumed 1.5 kg/m²: 500 m² × 1.5 kg/m² = 750 kg, and 750 kg ÷ 25 kg = 30 containers. Adding 10 % for detailing, hose clearance and edges gives 825 kg ÷ 25 kg = 33.
- Per container: 25 kg ÷ 1.5 kg/m² = approximately 16.7 m².
- Caveat: the sheet calls this an assumed consumption, and the reliable number comes from your own calibration panel. The render coverage calculator builds the full materials list.
How old does the basecoat or substrate have to be?
Reinforced layers made with Ceresit CT 85, ZU, CT 190 or CT 100 are rendered at more than three days old, and CT 87 at more than two days, each primed with CT 16. Cement and cement-lime renders need more than 28 days and concrete more than three months, both at 4 % moisture or below.
Which machines and pressure does the sheet recommend?
The sheet names SPG Baumaschinen PG 20 and Wagner PC 830, with a minimum recommended pressure of 2 bar through a ≥ 6 mm nozzle. Operating pressure changes with machine type, hose length and pumping height, so the contractor sets the final method from their own test application — and any unit not on that list is a question for Ceresit before the facade starts.
Can it be used indoors?
Yes — it is described as a decorative thin-layer render for indoor and outdoor applications, and several substrates on the sheet are interior-only: gypsum below 1 % moisture, gypsum-fibre boards, plasterboard, chipboard and sound existing paint coats. Rooms are aired after application until the odour has gone.
How is an aged CT 174 Machine facade refreshed?
The sheet's renovation route is repainting, with Ceresit CT 54 silicate paint or the CT 48 and CT 49 silicone paints. That keeps a tired elevation on a documented pathway and makes maintenance a repaint rather than a re-render.
Technical Documentation