Pressure-treated lumber can be painted, but it does require more time and patience than painting regular lumber. Pressure-treated lumber needs to cure for at least three months before it is painted.
After waiting three months for the wood to cure, painting pressure-treated lumber begins by cleaning the lumber with a stiff-bristled brush and soapy water. If the water soaks in, the lumber is dry enough to paint. Prime the lumber with an exterior-grade primer suitable for pressure-treated wood. Once the primer has dried, a top coat of pressure-treated-specific paint is applied. Latex paint works better than oil on pressure-treated lumber.