Reading the old paint before choosing the new
The quickest way to understand what an exterior repaint will involve is to look closely at the paint that's on the house now. Every kind of failure has a cause, and each cause has its own fix. A painter who reads those signs before writing a proposal can tell you what preparation the job needs, and why, before anyone opens a can.
What the Cedar Rapids station lists
NOAA's engineering weather data for Cedar Rapids lists a 50-year basic wind speed of 90 mph (3-second gust at 33 feet), a 100-year rainfall rate of 3.3 inches per hour and about 54 freeze-thaw cycles in an average year. Those are design figures from the station, quoted as NOAA gives them. Two of them bear directly on exterior paint: the freeze-thaw count and the rainfall rate.
A freeze-thaw cycle is a crossing of freezing in both directions. When water has found its way behind a paint film, through an open joint, a split board or a gap at a window head, each crossing can freeze it, swell it and pry the film a little further from the wood. A hard rain tests every joint, sill and drip edge, which is where water gets in.
Peeling down to bare wood
Paint that lifts off in flakes and shows bare wood underneath usually means moisture got behind it. The fix starts with finding the water: a failed caulk joint, a missing drip cap, a gutter that overflows onto the wall, or damp coming from inside the house. Then the loose paint is scraped back to a firm edge, the edges are sanded so they don't show through, and bare wood is primed. Painting over peeling paint without stopping the water just puts a fresh coat on the same problem.
Blisters
Bubbles in the film can be heat blisters, from painting a hot wall in direct sun, or moisture blisters, from water pushing out from behind. Cut one open. Bare wood with water inside points to moisture. Paint underneath points to heat. Moisture blisters need the source traced, just like peeling.
Chalk
Rub a dark sleeve along the siding. If it comes away coated in powder, the old paint is chalking as its resin breaks down in sunlight. New paint won't hold well on chalk, so the walls need a thorough wash, and sometimes a bonding primer, before the first finish coat.
Mildew and dirt
Gray or black spotting that comes back after a rinse is often mildew, which grows on shaded, damp walls. It should be cleaned off with a suitable cleaner and rinsed well before priming, or it can grow through the new paint.
Cracking and alligatoring
Fine cracks, or a pattern like reptile skin, mean old layers have lost their flexibility. Light cracking can be sanded and primed. Deep, widespread alligatoring may need the paint taken off back to a sound surface, which is slow work and a big part of the price on those walls. Our surface preparation guide explains how prep is matched to the surface.
Older paint and the lead rule
On a house built before 1978, scraping and sanding the old film can disturb lead-based paint. 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. EPA runs the program in states it has not authorized, and Iowa is one of the states it lists as running its own EPA-authorized program.
On such a house, you can ask the painter whether the firm holds RRP certification and how the crew will contain chips and dust: plastic on the ground, misting while scraping, careful cleanup and bagged debris.
How Iowa's rule describes the work
The Iowa rule that defines construction for contractor registration (871 IAC 23.82, used by Iowa Code 91C.1) lists painting and wall covering contractors, including house painting, as construction. That definition is quoted as the rule words it.
What to ask before the work starts
- Which faults did you see on my house, and what caused them?
- Where is water getting in, and will that be fixed before painting?
- How far back will loose paint be scraped, and which areas get primer?
- Which product goes on each surface, and how many coats?
See our exterior painting page for the full sequence of an outside job.