Paint dries on the air's schedule, not the crew's
A coat of paint is a liquid when it goes on and a film when it's finished. In between, water or solvent has to leave it, and the air around the wall decides how fast that happens. Warm, dry air takes moisture readily. Air that is already carrying a lot of water takes it slowly. That one idea explains most of the timing questions you'll have about a Lafayette paint job: how long to wait between coats, when the crew can start in the morning, and why a painter may stop early on a still, muggy afternoon.
What NOAA's Lafayette station records
NOAA's engineering weather data comes from a station named for Lafayette, and two of its figures bear on painting.
- Warm, damp hours. At Lafayette, NOAA counts about 2,531 hours in an average year with the wet-bulb temperature above 73°F, and about 4,176 hours above 67°F. Wet-bulb temperature folds heat and moisture into one reading, so high wet-bulb hours are hours when the air is both warm and carrying a lot of water vapor.
- Rain, wind and freezing. The same data lists a 100-year rainfall rate of 4.5 inches per hour, a 50-year basic wind speed of 120 mph (3-second gust at 33 feet) and about 9 freeze-thaw cycles in an average year.
These are long-term and design figures for the Lafayette station, not a forecast for your week. The cards below print them in full, with NOAA's link.
Reading damp-air hours the way a painter does
Latex paint dries as its water evaporates. When the air is close to saturated, evaporation slows and the film stays soft longer. A soft film picks up dust, can be marked by a ladder foot or a drop cloth, and may not be ready for a second coat when the label's standard recoat time says it should be. Labels usually give those times for moderate temperature and humidity, so on a damp day the real wait runs longer.
What a careful painter does about it:
- starts exterior coats only once the wall is dry to the hand, and stops early enough for the film to firm up before evening dampness settles on it;
- checks the surface by touch rather than by the clock before recoating;
- keeps the air moving indoors, with fans or the air conditioning running, while walls dry;
- reads the product label for the conditions it allows, and follows the label over habit.
Ask how the painter decides a coat is ready for the next one. "Dry to the touch" and "ready to recoat" are not the same thing, and the gap between them widens when the air is damp.
Rainfall rate and the small joints that keep water out
A design rainfall rate describes how hard rain can fall, not how often. For paint, the point is that wind-driven water finds every open joint in the wall. Before any color goes on, the parts that decide how long the job lasts are the small ones:
1. caulk at trim joints, around window and door casings and at corner boards, after old cracked caulk is cut out; 2. sills and the lower edges of siding, where water sits longest, scraped back, primed and coated; 3. the top edges of trim, which catch the rain and are often the first place paint lifts.
Some gaps have to stay open so siding can drain, so ask which joints will be sealed and which will be left alone. Our exterior painting page covers washing, scraping and priming in more depth.
About 9 freeze-thaw cycles
It isn't many, but each cycle means water sitting in a crack can freeze and expand. Sealing cracks before painting helps the coating ride through those nights, and it's one more reason the preparation lines in a proposal deserve as much attention as the paint line.
The statute on the card
One of the cards on this page is Louisiana's, and it quotes R.S. 37:2150.1 together with a line from the State Licensing Board for Contractors. It sets a $7,500 project-value mark for what the law calls home improvement contracting on an existing residence, and the board's own $50,000 line for its residential license. That's general wording about home improvement, and we don't stretch it to any particular paint job; the card links to the text itself.
A Lafayette proposal worth signing
Before you agree to anything, the written proposal should say:
- which surfaces are included and which are not;
- how each surface will be cleaned and prepared, including caulking and spot priming;
- the products and sheens by name, and the number of coats;
- what happens on a wet or muggy day: whether work stops, and how the schedule moves.
Compare those lines across bids before you compare totals. The pricing guide explains why two painters can price the same house differently.