Why do you keep referring to applying the paint or stain at the spread rate [square feet per gallon] recommended by the manufacturer? Is it really that important? Isn't it reasonable to try to get extra "mileage" out of a gallon of paint?
It is important because how thick or thin the coating is applied impacts many properties. This applies to paints, primers, stains, clear coatings and elastomeric coatings. Some properties directly impacted by spread rate (and thus film thickness) are:
- Hiding and Uniformity of Appearance
- Crack Resistance
- Mildew Resistance
- Stain Blocking (primers)
- Corrosion Resiatance (primers)
- Flow-Out and Smoothness (which affects appearance and durability)
- Scrub Resistance
- General Longevity of Protection While hiding may, for example be acceptable when a coating is spread thin, other properties can be seriously compromised.