Deciding to Brush or SprayBelieve it or not, lots of people brush paint on their house exterior. And I mean the whole house, not just trim. Brushing means a quicker start time, less masking, more attention to details, and if cost is a concern, less paint required.
Spraying your exterior means you can cover tricky obstructions from utilities (wires, pipes, gas meters) and architectural details. But you will lose paint from overspray.
Quantity With BrushingOne gallon of exterior acrylic-latex on a clean, painted or primed surface--a minimum of porosity--is estimated by manufacturers to cover about 400 square feet. I've found this to be true, though I can squeeze out even more than that.
Quantity With SprayingThe same amount of paint will cover about 150-200 square feet of wall. I would be more careful and even estimate more like a 1:3 ratio (1 gallon brushed on will require 3 gallons when sprayed on).
Dripping is about the only factor that will affect quantity of paint used with hand-brushing. But spraying has a few more factors that will increase the quantity needed:
- Wind: Even a mild, 5-10 mph wind is enough to blow away paint.
- Paint Remaining in Sprayer and Hoses: When you are finished, remember to pump paint remaining in the hose back into the can instead of disposing of it. Paint residing in even 25' of hose can add up.