How to Finish Pressure-Treated Wood

Apply a preservative to pressure-treated wood as soon as you have completed the building project, but wait at least one to two months before painting or staining. The preservative will slow drying and keep the boards smooth. Paints and stains, however, won't penetrate until the wood has lost a significant amount of moisture.

Prepare the wood by sanding lightly by hand or going over it with a wire brush. The process by which wood is pressure treated causes it to develop more splinters than non-treated wood might have. Remove as many of these splinters as possible.

Add a fungicide to the paint or stain you are going to apply. Although pressure treating strengthens the wood against decay, it does little to prevent surface infestation of mold and mildew.

Paint or stain as you normally would.