Sand for Rendering: Which Sand for Each Coat and How Much per m²
By David Polido, CEO of Chambino Areias and INERCORChambino Areias supplies sand in Portugal only (Seixal, near Lisbon). Prices exclude VAT; delivery to site from 5 t across the Lisbon and Setúbal region; smaller orders are collected at the pit.
Quick answer
Traditional render normally uses two sands: coarse washed sand 0/4 in the base coat (cement to sand at about 1:5) and fine washed sand 0/1 in the finish coat (1:5 to 1:6). An interior wall with 1.5 cm of render takes about 16 kg of 0/4 sand and 8 kg of 0/1 sand per m².
Below are the coats, the quantities per m² and a full worked example.
The coats of a render and the sand for each
Spatterdash (key coat). A thin, rough coat, richer in cement (around 1:2), that helps the render grip smooth surfaces. It is made with 0/4 sand.
Base coat. The coat that evens out the wall. It uses coarse washed sand 0/4 at 1:5 (1:4 to 1:5 in practice), about 1.5 cm thick indoors and 2 cm outside. Tagus river sand, with its rounded grain, is also used in render mortars.
Finish coat. A coat of about 0.5 cm that gives the final texture. It uses fine washed sand 0/1 at 1:5 to 1:6. Grains up to 1 mm leave a smoother surface, ready to paint.
Pit sand 0/4, which is not washed, is normally kept for fill and bedding, not for render. For the difference between washed and unwashed sand, see washed sand vs natural sand.
How much sand per m² of render
The sum is area × thickness = volume; volume × 1.6 = tonnes of sand (see how much a cubic metre of sand weighs). The finish coat (0.5 cm) is part of the total thickness.
| Render | 0/4 sand per m² | 0/1 sand per m² |
|---|---|---|
| Interior, 1.5 cm, with fine finish coat | about 16 kg | about 8 kg |
| Interior, 1.5 cm, base coat only | about 24 kg | — |
| Exterior, 2 cm, with fine finish coat | about 24 kg | about 8 kg |
| Exterior, 2 cm, base coat only | about 32 kg | — |
These figures have no margin. Add 10 to 15 % for waste and uneven walls. Very crooked walls need more thickness, and anything over 3 cm is best built up in several coats.
Mix and cement
The mix is measured by volume; a 25 kg bag of cement is about 19 litres.
- Base coat at 1:5: about 95 litres of 0/4 sand per bag of cement (≈ 152 kg, close to six 25 kg bags), or about 9 to 10 buckets of 10 L.
- Finish coat at 1:6: about 114 litres of 0/1 sand per bag of cement (≈ 182 kg, close to seven 25 kg bags).
For other mixes, see how much sand and cement you need.
Example: 30 m² of interior wall
Base coat with 0/4 sand (1 cm): 30 × 0.01 × 1.6 ≈ 0.48 t; with a 10 % margin, about 0.53 t, i.e. 21 bags of 25 kg
Finish coat with 0/1 sand (0.5 cm): 30 × 0.005 × 1.6 ≈ 0.24 t; with the margin, about 0.26 t, i.e. 11 bags of 25 kg
Cement: about 5 bags of 25 kg
For quantities like these, the 25 kg bag is the most practical format: it fits in a car and stores in little space. Orders below the delivery minimum (5 t across the Lisbon and Setúbal region) are collected at our sand pit in Seixal. For large areas, both sands also come in big bags of about 1 t.
Where to order
The Chambino Areias sand pit is in Corroios, Seixal. See current prices for coarse washed sand 0/4 and fine washed sand 0/1 on their product pages. Work out your wall in the simulator (in Portuguese) and ask for a quote.
Frequently asked questions
Which sand is used for rendering?
Coarse washed sand 0/4 for the base coat and fine washed sand 0/1 for the finish coat.
How many kg of sand per m² of render?
On an interior wall at 1.5 cm, about 24 kg in total: 16 kg of 0/4 and 8 kg of 0/1 if there is a fine finish coat. Outside, at 2 cm, about 32 kg.
What is the mix for render?
1:5 for the base coat (1:4 to 1:5 in practice) and 1:5 to 1:6 for the finish coat, by volume.
Can I render with fine sand only?
The base coat is normally done with 0/4. Fine sand on its own needs more water and gives a mortar more prone to cracking in thicker coats; keep it for the final coat.
How many bags of sand do I need to render a 10 m² wall?
At 1.5 cm with a fine finish coat, about 7 bags of 0/4 and 4 bags of 0/1, margin included.