Why we Tint the First Coat of Paint

Interior and exterior paint have very different jobs to do; most importantly, exterior paint is protecting a structure from the elements, sun, rain, humidity and UV, whereas interior paint is generally just an aesthetic feature. If interior paint looks good, it is good.

Exterior paint, on the other hand, has a job to do, and if primer and two coats are needed to do that job, then it needs those two coats everywhere.

If 5 or even 3% of a house accidentally receives only one finish coat instead of two, those areas are likely to weather sooner than the rest of the paint job.

I discovered this accidentally when Anna had mixed a slightly different color for the second coat, as she often manually mixes paints from what is available to save driving to the store, and when applying it hit me that with the subtly different tones, I could see where had received the full two coats v's where had only one, even when dry.

Since discovering this, it has become our standard approach on full exterior paint jobs:

white primer, a slightly tinted first coat, and then the final coat. It takes very little extra effort, but makes it much easier to verify that every surface has received the same level of protection.

The tint need only be very subtle - just enough to distinguish one coat from the next without effecting the final color.