Dosing and coverage

Coverage is the number professionals ask for first and the one that is hardest to give honestly, because it depends on the surface as much as on the product. A square metre of sealed tile and a square metre of raw brick do not take the same amount, and a quotation built on the wrong one of those loses money in one direction or the other.

The working figure is 70 square metres per litre, or 7 square metres per 100 ml, on smooth and sealed surfaces applied as a thin, even layer. That is the figure the coverage calculators on the site use. A table per surface class (smooth and sealed, porous and unsealed, textile) follows with the technical data sheet; until then, treat 70 m² per litre as the ceiling and expect less on anything that absorbs.

Estimating an edge job in the meantime. Most professional application is linear rather than area based: metres of skirting, frames and thresholds, not square metres of wall. Measure the perimeter of each room, add the door and window frames, and treat that running length as your unit. Convert to area with 70 m² per litre for smooth surfaces, and allow more for anything porous.

What increases consumption. Porous surfaces, which absorb. Rough and textured surfaces, which have more real area than their measurement suggests. Detailed shapes such as bed frames and racking, where much of the product goes past the target. Cold surfaces, where the spray behaves differently. Inexperienced applicators, who saturate.

What reduces it. Sealed and smooth surfaces. A correctly sized nozzle at a consistent pressure. Detail work with a cloth instead of spray. And measuring the job before you fill the tank.

Reapplication interval: up to 6 weeks under typical conditions, and sooner on high-contact surfaces or where treated edges are wet cleaned. Reapplication consumes the same quantity as the first application; there is no reduced maintenance dose.

Planning a contract. Take the running length per site, apply the coverage figure once it is published, add a working margin for detail and waste, and price the visit rather than the litre. Then record actual consumption per visit for the first few visits and correct your own figure from real data. A number you measured on your own sites beats a number from any data sheet.