Incised vs. surface-treated framing: what's the real difference?

The distinction that matters most is preservative penetration versus moisture exclusion.

Incised, pressure-treated lumber

Small incisions help preservatives penetrate the wood.

• Preservative is introduced into the lumber under pressure.
• Incising can improve penetration in species that are difficult to treat.
• It is designed to resist fungal decay and insects, according to the treatment specification.
• It is not waterproof; wood can still absorb moisture, swell, shrink, and crack.

Surface-treated or coated framing

A coating or topical preservative protects the surface to the extent allowed by the product.

• A brush-on preservative or water repellent primarily acts at the surface.
• It generally does not provide the same penetration or standardized protection as properly pressure-treated structural lumber.
• Coatings can wear, crack, or require reapplication.
• A water-repellent coating is not necessarily a wood preservative, and neither automatically makes framing waterproof.