Dunn-Edwards FLEX-PRIME® Select
Crack-bridging masonry primer
Product code FPSL00-1
Flex-Prime is what we use when a stucco wall has a multitude of hairline cracks and the finish has to come out scarless. On cracked Phoenix stucco it covers closer to 100 sq ft per gallon, and its 4–6 hour recoat adds a day to a two-day job.
Flex-Prime is best when there are a multitude of smaller hairline cracks and you want a scarless finish. When cracks are larger than what would be considered hairline, we have other techniques for fixing them in a scarless way. The data sheet puts a number on where that line falls: one coat covers cracks no greater than 1/32 of an inch, and anything wider needs patching material first.
The sheet says 100 to 250 square feet per gallon. On cracked Phoenix stucco it is closer to the 100 at the low end. It is a high-build product—it is meant to go on heavy, because that is what fills the cracks.
The recoat on this is four to six hours, where most of what we use is two to four. If we were applying Flex-Prime to an entire house on a two-day job, it would definitely make it one day longer, so at least a three-day job. If a quote for crack work looks slower than the one next to it, this is usually why.
Flex-Prime is only made in the Select grade. There is no Premium version, so this is the one to buy.
| Coverage | 100–250 sq. ft. per gallon (closer to 100 on cracked stucco, in our experience) |
|---|---|
| VOC | 50 g/L maximum as supplied (25 g/L maximum reactivity-adjusted) |
| Dry to touch | 1–2 hours |
| Recoat | 4–6 hours |
| Film build | 6.1–8.5 mils wet / 2.5–3.5 mils dry |
| Application | Brush, roller, or airless |
| Temperature | 50°F minimum |
| Masonry pH | Rated for surfaces up to pH 11 |
| Crack bridging | One coat for cracks no greater than 1/32”; wider cracks require patching material first |
| Grades | Select only—no Premium version is made |
| Substrates | Stucco, tilt-up concrete, poured-in-place concrete, brick, smooth concrete block, galvanized steel, ferrous and non-ferrous metals |
Manufacturer figures from the Dunn-Edwards product data sheet. Coverage figures marked “in our experience” are ours, measured on our own jobs in the Phoenix valley. Sources: https://www.dunnedwards.com/product/flex-prime-select/ and https://www.dunnedwards.com/wp-content/uploads/2015/01/EN-FPSL00-PDS.pdf. Dunn-Edwards® and FLEX-PRIME® are trademarks of Dunn-Edwards Corporation. We are not affiliated with or sponsored by Dunn-Edwards; we buy this product at retail like anyone else.