How Much Render for a Wall?

How We Calculated This

Render quantity is calculated from the wall area, render thickness, and coverage rate of the product:

• Wall area: 3m × 2.4m = 7.2m²
• Render thickness: 15mm (two-coat system: 10mm scratch coat + 5mm top coat)
• Coverage per 25kg bag at 15mm: ~2–2.5m²
• Bags needed: 7.2 ÷ 2.4 = 3 bags

If Mixing Your Own (Traditional Render)

For a traditional sand and cement render mixed on site:

• Scratch coat (10mm): 4:1 sharp sand to cement
• Top coat (5mm): 5:1 sharp sand to cement, with lime for workability
• Volume of render: 7.2 × 0.015 = 0.108m³
• Sharp sand needed: ~3 x 25kg bags or roughly 175kg
• Cement needed: ~1.5 x 25kg bags (35–40kg)
• Plasticiser or lime: as per manufacturer’s instructions

Types of Render

• Sand & cement: traditional, cheapest, requires painting
• Monocouche (through-coloured): one-coat system, no painting needed
• Silicone render: flexible, self-cleaning, premium finish
• Lime render: breathable, ideal for older/listed buildings
• Acrylic render: thin-coat system over insulation boards

Render Thickness Guide

• Two-coat sand & cement: 15–20mm total
• Monocouche: 15–20mm (single coat)
• Thin-coat/silicone: 4–8mm (over insulation or flat substrate)
• Lime render: 15–25mm (two or three coats)

Surface Preparation

Before rendering, ensure the wall is:

• Clean: remove loose material, moss, and old paint
• Dampened: mist with water to prevent the wall sucking moisture from the render
• PVA or bonding agent: apply to smooth or low-suction surfaces
• Beading: fit stop beads at edges and bellcast beads at the base

Typical UK Costs

• Pre-mixed render (25kg bag): £8–£15
• Monocouche render (25kg bag): £15–£25
• Silicone render (25kg bucket): £40–£70
• Sharp sand (bulk bag): £40–£60
• Cement (25kg bag): £5–£8
• Professional rendering labour: £30–£50 per m²