Decorative render calculator
Decorative (textured) render is applied in a single layer as thick as its grain, so the grain size decides the consumption: a coarse grain uses more than twice as much as a fine one. The calculator turns the area and the grain into kilograms and packs.
Your measurements
Result
- Render needed
- 50 kg
- Packs to buy
- 2 pcs
Order all the tinted render from one batch so the shade is the same across the whole façade.
How the calculation works
- Consumption per m² depends on the grain: about 1.5 kg/m² for fine (1–1.5 mm), 2.5 kg/m² for medium (1.5–2 mm) and 4 kg/m² for coarse (over 2 mm).
- Quantity (kg) = area × consumption per m².
- Packs = kilograms ÷ pack size, rounded up.
Worked example
For 20 m² of façade with medium-grain render: 20 × 2.5 = 50 kg, which is 2 packs of 25 kg.
What the calculator assumes
- The render is applied in one layer as thick as the grain.
- The values are for typical mineral, acrylic or silicone renders; scratch or “bark” textures differ slightly.
- The surface is primed first with the primer recommended by the manufacturer, usually tinted to match.
When to adjust the result
- On an uneven background the real consumption increases — keep a reserve.
- Order all the tinted render from one batch so the shade is uniform across the façade.
- The reinforced base coat of an insulation system is not included.
Applying decorative render evenly
Decorative render needs a sound, even base coat and the primer the system specifies, often tinted to the final colour. Work one wall from corner to corner without stopping, wet on wet, because joints between dried and fresh render stay visible.
Avoid working in direct sun, wind, rain or below about 5°C, and order the whole façade from one batch so the colour stays even. Grain size determines consumption — a 2 mm grain uses noticeably more material than a 1.5 mm grain.
Frequently asked questions
How much decorative render per square metre?
Roughly 1.5 kg/m² for a 1–1.5 mm grain, 2.5 kg/m² for 1.5–2 mm and around 4 kg/m² for coarser grains. The product data sheet gives the exact figure.
Mineral, acrylic or silicone render?
Mineral render is vapour-open and inexpensive; acrylic is flexible and comes in many colours; silicone repels water and stays clean longer. Match it to the insulation system and the exposure of the wall.
Silicone, silicate or acrylic render?
Silicone render repels water and stays clean longest; silicate is very vapour-open and suits mineral bases; acrylic is elastic and cheaper but less vapour-open.
Do I need primer under decorative render?
Yes, almost always — it evens out absorption and improves adhesion; use the one specified for the render.