Hi Michael,

for 200 sqm you would require 3 X 15 L drums.

A theoretical calculation would involve multiplying your 200sqm by 2 (2 coats) and dividing by estimate of 8 sqm/L per coat.

This amounts to approx 50 litres or 3.3 X 15L drums.

Since one can expect slightly greater coverage from the second coat, 3 drums should be sufficient!