Staining pressure-treated wood is a recommended practice. While inherently resilient, it's not impervious to moisture and UV exposure. Staining treated wood is feasible and recommended for enhanced protection and longevity. Applying stain and sealant safeguards against degradation, prolonging its life span. These measures shield the wood from environmental threats while augmenting its aesthetic appeal, ensuring your investment endures the test of time.

Applying a sealer or topcoat after staining wood is highly recommended, though not always strictly required. A sealer protects the wood from moisture, UV rays, and weather-related issues, which is especially important for outdoor surfaces like decks and fences. It also enhances the stain's durability, prevents fading over time, and gives the wood a cleaner, more professional-looking finish. For some indoor applications, a sealer may not be necessary, depending on the type of stain used and the level of protection needed. It's always best to check the stain manufacturer's recommendations and consider the wood's intended use and exposure when deciding whether to apply a sealer.

The opposite is actually true: Wood stains tend to appear lighter when they’re fully dry. However, stains may darken as they weather and oxidize with age. Stains might also darken on surfaces left in direct sunlight, as UV rays can break down pigment particles and cause them to darken over time.

It is definitely worth sanding a deck to ensure the wood absorbs new stain. Sanding a deck removes the outer layers of aging wood, allowing the stain to penetrate. It also gives a fresh look to the entire surface as part of the deck refinishing process. Without sanding, your stain or sealant is less likely to absorb into the wood. While sanding a deck is a time-intensive project, the rewards are noticeable and long-lasting.