Moisture is the main character
Ask most people what weather does to paint and they'll say sun. In Tyler the more useful question is about water in the air. In an average year at Tyler, NOAA counts about 1,918 hours with the wet-bulb temperature at 73°F or higher, against about 330 hours at 93°F or hotter, with a 100-year rainfall rate of 4.0 inches per hour. The muggy hours outnumber the very hot ones many times over.
That changes the painting problem. Coats take longer to give up their water. Dew can settle on a wall late in the afternoon. Shaded siding and north-facing trim stay damp, and damp, shaded surfaces are where mildew, algae and moss get started.
Mildew comes off before paint goes on
Paint applied over live mildew will grow it back through the new film, often within a season. So the first job on most exteriors is cleaning, and it's worth seeing it spelled out in a proposal:
- Identify it. Dark specks that don't smear like dirt, and that lighten under a drop of diluted household bleach, are usually mildew.
- Kill and rinse. A mildewcide wash, or a cleaner the paint maker specifies, followed by a thorough rinse.
- Let it dry. Wood and masonry that look dry on the surface can still hold moisture. Many paint labels give a maximum moisture content; a crew with a moisture meter can check it.
- Fix the cause. Shrubs pressed against the siding, a gutter overflowing onto a wall, or a sprinkler hitting the house will bring mildew back. Trimming and redirecting water is cheap compared with repainting.
Choosing coatings for a damp climate
Exterior acrylic paints breathe, which lets moisture in the wall escape rather than pushing the film off as blisters. Many are sold with mildew-resistant additives; that's worth asking about for shaded walls. On bare wood, a primer the topcoat's maker approves comes first. Glossier sheens shed water and dirt more readily, which is why trim, doors and handrails are usually satin or semi-gloss. The paint sheens and finishes guide explains the trade-offs.
Indoors, bathrooms and laundry rooms see the same problem in miniature. A paint labeled for high-humidity rooms, a working exhaust fan and patience between coats do more than any color choice.
Planning the painting day
On an exterior in humid weather, the hours in the middle of the day are often the safest window:
- Start after the dew has burned off, not at first light, so paint isn't going onto a film of water.
- Stop early enough that each coat can set before evening dew returns. The can lists a minimum temperature and often a time before rain or dew; both matter.
- Watch the forecast for heavy rain. A sudden downpour on fresh paint can wash it down the wall or leave it spotted.
- Allow extra time between coats. Recoat times on labels lengthen when the air is humid.
The cold side of the year
Winter is shorter than summer here, but it isn't absent. NOAA's engineering weather data for Tyler lists about 20 freeze-thaw cycles in an average year. Each cycle can freeze water that has worked behind a cracked caulk joint or into bare wood, which is why sealing gaps and spot-priming bare spots belong in any exterior quote. Exterior paint applied on a cold day also needs time above its minimum temperature after the crew leaves.
Lead in older paint
For a home built before 1978, the existing paint may contain lead, and scraping or sanding it makes dust. Under EPA's Renovation, Repair and Painting Rule, anyone paid to do work that disturbs paint in homes, childcare facilities and preschools built before 1978 must hold RRP certification, firms included, even sole proprietorships, and their workers must be trained in lead-safe work practices. If your house is in that group, ask the painter whether their firm holds RRP certification and how they'll contain and clean up the dust.
Questions to put to a painter
- How will you clean mildew, and how will you confirm the surface is dry before priming?
- Which primer and which topcoat, by product name, and how many coats?
- Which hours of the day will you apply exterior coats, and what makes you stop?
- What is caulked, and with what?
More on scope and products is on our exterior painting and interior painting pages, and the pricing guide covers what changes a price.