Render & Stucco Calculator — Base Coat, Mesh & Finish
Calculate kg of base coat render, finish coat, reinforcing mesh and primer for rendered facades and ETICS-style systems. Use the kg/m² inputs for the selected manufacturer system; traditional lime-cement and monocouche systems require product-specific rates.
How much render do I need per m²?
The base or levelling coat runs about 5–8 kg/m² (1–1.6 lb/sq ft) at 6–8 mm thick. The finish depends entirely on the system: thin-coat silicone 2–3 kg/m² (0.4–0.6 lb/sq ft), monocouche 10–12 kg/m² (2–2.5 lb/sq ft), traditional two-coat lime-cement 22–25 kg/m² (4.5–5 lb/sq ft) at 15 mm. All three cover the same wall — picking the wrong one is a fourfold error, not a rounding one.
How much mesh and primer go with the render?
Reinforcing mesh is the facade area plus about 15%, because every corner and opening needs a lap of at least 100 mm (4 in). Primer covers roughly 6–8 m² per litre, or 245–325 sq ft per US gallon. Both are sold by the bag, roll or tub, so round each one up on its own rather than off the total.
ETICS layer build-up
Consumption guide (typical values)
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How the render calculator works
- 1Facade area = wall or ETICS board area (m²), minus window reveals if embedded
- 2Base coat / levelling coat: area × kg/m² rate (typically 5–8 kg/m² at 6–8 mm — about 1.0–1.6 lb/sq ft at ¼ in); board adhesive is not separately modelled here
- 3Reinforcing mesh: area + 15% for laps at corners (100 mm / 4 in minimum lap) and openings
- 4Primer: area ÷ coverage rate (typically 6–8 m²/L, or 245–325 sq ft per US gallon)
- 5Finish coat: area × kg/m² (thin-coat silicone: 2–3 kg/m², or 0.4–0.6 lb/sq ft; monocouche: 10–12 kg/m², 2.0–2.5 lb/sq ft)
- 6All materials sold by the bag or kg — round up to nearest bag
Worked example
ETICS system on an 80 m² (860 sq ft) facade. Base coat 6 kg/m², silicone finish coat 2.5 kg/m² — 1.2 and 0.5 lb/sq ft. Mesh 160 g/m².
Base coat: 80 × 6 = 480 kg — 24 bags of 20 kg, or 1,060 lb. Mesh: 80 × 1.15 = 92 m² (990 sq ft). Finish coat: 80 × 2.5 = 200 kg (10 bags, 440 lb). Primer: 80 ÷ 7 = 12 L, about 3 US gallons.
Frequently asked questions
What is the difference between render and plaster?
Render is applied to external walls — it must be weather-resistant, vapour-permeable and frost-proof. Plaster is used internally — it is more refined, less weather-resistant and typically thinner — 6–12 mm against 10–20 mm for render, roughly ¼–½ in against ⅜–¾ in.
Do I need mesh in render?
Reinforcing mesh is mandatory in all ETICS/EIFS systems to prevent cracking. It is also recommended in traditional render at re-entrant corners, over mixed substrates and where movement joints are required. Use alkali-resistant (AR) glass fibre mesh.
What is monocouche render?
Monocouche (single-coat) render is a factory-mixed pre-coloured render applied in one 12–15 mm (½–⅝ in) coat directly over the substrate. It is faster than two-coat systems and eliminates a separate paint finish — available in a wide range of colours.
How long does render take to dry before painting?
Traditional cement render: 28 days minimum before applying masonry paint. Monocouche does not require painting. Thin-coat silicone finish is the final coat. In cold or damp weather, curing times can double — protect fresh render from rain, frost and direct sun.