I had someone powerwash and paint the whole white facade around the front door and foyer window, but by the next season the paint is chipping and peeling off. It’s not wood, it might be some kind of composite material.

Do I need to sand all of the previous paint off?
Do I need to prime?
Is the emerald line of Sherwin Williams exterior paint good enough to finish?

who entire white part


more peeling

  • 2
    A powerwash is not a suitable primer...
    – Solar Mike
    Jul 12, 2021 at 17:46
  • It's not even suitable prep. It could be the first part of suitable prep. Jul 12, 2021 at 19:02
  • TBH, I'm not sure why you had the white PVC trim painted white to begin with. That stuff's designed to survive forever without paint at all.
    – FreeMan
    Jul 13, 2021 at 17:28
  • @FreeMan it was already painted when we purchased the house Jul 13, 2021 at 17:35
  • @FreeMan You can see that the PVC white is not as bright as the painted white so if bright white is desired then you have to paint.
    – MonkeyZeus
    Jul 13, 2021 at 17:51

1 Answer 1


The good news is that it's PVC trim so you shouldn't experience any rot issues.

The bad news is that's it's PVC trim so paint doesn't adhere to it easily.

Properly, the trim should have been:

  1. Washed: by hand or light pressure-washing
  2. Let dry
  3. Scoured with 220 grit sandpaper so that paint can better adhere to it
    • I believe the same effect can be achieved by rubbing down the surface with isopropyl alcohol
    • If sanding then rinse off the dust and let dry
  4. On a shady day:
    • Painted with a PVC paint primer which accepts latex paint
    • Painted with a high quality exterior latex paint of the desired color

As you might have guessed by now you will have to get all of the paint removed so that you can perform step #3.

The shady day is important because in direct sunlight the paint will dry too fast and not properly bond to the substrate.

  • Looks like the previous job didn’t have the sandpaper or the primer. It was destined to fail. Also to note, that side of the house is in the shade most of the day so finding the right weather is a bit on the easier side. Jul 13, 2021 at 1:39
  • 2
    @FrancisJohn Hopefully you didn't pay a premium for this person to do such a sub-par job. If this was a professional painter then I'd be quite miffed that they didn't quote you for the proper prep work. If this was a "jack of all trades" then they presumably did exactly as requested without any additional thought.
    – MonkeyZeus
    Jul 13, 2021 at 12:47
  • 1
    Do note that painting PVC trim with "paint of the desired color" is OK, so long as the desired color isn't "dark". Darker colors will absorb more light, heating the PVC and cause it to expand more than it's designed to. It's not recommended. A new coat of white, though, shouldn't be any problem at all.
    – FreeMan
    Jul 13, 2021 at 17:27
  • 1
    @FrancisJohn I just got done answering your latest question and realized I had answered this question of yours as well, hah! Any luck with the paint work?
    – MonkeyZeus
    Aug 25, 2021 at 14:49
  • 1
    @MonkeyZeus didn’t start this project yet, soon though! Aug 25, 2021 at 15:32

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