Dunn-Edwards EZ-PRIME® Premium | Exterior acrylic wood primer
We prime new fascia on all six sides with EZ-Prime Premium before it goes up — back and cut ends included — because primer's real job is sealing moisture out of the wood, not making it look better. On bare sun-baked fascia it covers closer to 150–200 sq ft per gallon, not the 275–350 on the data sheet.
When we replace a rotted fascia board, the new wood gets primed on all six sides before it ever goes up. That includes the back and the cut ends — the faces nobody will ever see again once the board is nailed in place.
The reason is that it helps seal out moisture from entering the wood. Most people believe paint is only there to make something look better. That is only half true. Paint also has the job of protecting from the elements.
Primer is always used on parts that are not seen, and its main job is protecting the surface it is applied to from something that would damage it. That is the whole idea behind priming a board on all six sides — the faces you will never look at again are the ones doing the work.
On coverage: The data sheet says 275 to 350 square feet per gallon. On bare sun-baked fascia it is probably closer to 150 to 200. Old dry wood in this climate takes far more primer than the sheet suggests.
Sometimes new wood has some bleed-through and requires a second coat of primer before the finish coat goes on.
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: dunnedwards.com/product/ez-prime-premium and EZPR00 data sheet (PDF). Dunn-Edwards® and EZ-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.