Can I apply ArmorRenew to painted or sealed wood?

Yes, but those surfaces must have been painted at least 1-2 years prior. Remove previous coatings/sealers by power washing

Yes, but those surfaces must have been painted at least 1-2 years prior. Remove previous coatings/sealers by power washing any old and flaking paint as ArmorRenew, like all coatings, can only stick to what is under it, so if your existing paint is peeling, it should be stripped or sanded. ArmorRenew Primer should always be used for wood surfaces and is required to activate the lifetime warranty for wood surfaces. ArmorRenew can be applied to existing coatings if you are unable to remove them but they should be lightly sanded prior to coating for good adhesion, and the primer used. If your existing coating is really stuck on well, then sanding it for prep is fine. Pressure treated wood should be aged at least 1 year prior to coating.