No-Rot Gel
Yes. For best results allow the preservative to dry for as minimum of 24 hours. Use can then use a "builders bog" type filler and quality oil based primer then your choice of quality exterior oil or acrylic top coat.
Timber Preserver:
Yes, but with caution. Timber Preserver's active ingredeint, Copper Naphthenate, is also used as a paint drier in oil based paints. As such it can be prone to colour bleed. To paint over Timber preserver we recommend the following:
Allow at least 2 weeks to dry. Preferably more if practicable.
Use a quality stain block type acrylic primer such as those made by Zinsser or Dulux
If colour bleed through occurs with the primer, do not continue painting. Strip back the primer to bare timber and allow a further 2-3 weeks to dry.