Material estimates go wrong in two places: the area is measured casually, and the grain size's effect on consumption is ignored. Get those two right and any supplier can convert your numbers into an accurate quantity for their specific product.
Step 1 — Measure the real area
- Width × height for every wall face, in feet or metres — measured, not recalled.
- Subtract large openings (doors, windows) but ignore small ones; the offcut wastage roughly cancels them.
- Add returns, parapets, pillars and boundary-wall faces — the surfaces everyone forgets and then runs short on.
- Keep elevation faces separate from compound walls in your notes; you may choose different grains for each.
Step 2 — Understand what drives consumption
Texture consumption is not one number like paint, because the layer thickness follows the grain:
- Grain size: coarse dana lays thicker, so a coarse wall consumes more kilograms per square foot than a fine one. This is the biggest variable.
- Surface evenness: an undulating wall takes more material to level than a true one.
- Applicator hand: heavy trowelling uses more; it is worth asking who is laying it.
Step 3 — Ask the supplier the right question
Not "what is your coverage?" but "what is the coverage of this grain, at the thickness you recommend, on a plastered wall?" A supplier who answers per grain size is estimating; one who gives a single figure for everything is advertising. Coverage is a property of a specific product laid a specific way, which is why we quote it against your wall details rather than printing one number here — send your measurements through the contact page and we will size the material for the job, including a sensible margin.
Why a margin matters
Running short mid-wall forces a joint (see why wet edges matter), and a later batch of natural stone can vary subtly in shade. Ordering the full job plus a small reserve from one batch avoids both problems — the reserve also serves future repairs in a guaranteed-matching grain.
Frequently asked questions
Can I calculate from the bag weight alone?
Only once you know that bag's coverage at your chosen grain and thickness — which is exactly the per-product question above.
Does the binder change the quantity?
The binder is calculated alongside the dana as part of the system; ask for both quantities together so they arrive matched.
What about primer?
Primer is measured like paint, per square foot of the same area you measured in step 1 — one measurement serves all three materials.