How does Douglas Fir compare to cedar, pine, and pressure-treated lumber for outdoor structures?
Wood species selection is one of the most important decisions in any outdoor structure. Here’s how Douglas Fir — the material used in every NORWEH kit — compares to the most common alternatives:
Douglas Fir vs. Cedar
- Douglas Fir is significantly stronger and stiffer — better suited for structural spans and heavy loads like snow
- Cedar has slightly better natural decay resistance in ground-contact applications, but for above-grade timber framing Douglas Fir performs equally well when properly sealed
- Douglas Fir’s straight grain gives it a more refined, architectural appearance for exposed timber work
Douglas Fir vs. Pine
- Douglas Fir is considerably harder and more dense than most pine species
- Pine is more susceptible to denting, warping, and structural fatigue under load over time
- Douglas Fir holds fasteners more securely — critical in structural timber connections
Douglas Fir vs. Pressure-Treated Lumber
- Pressure-treated (PT) lumber is chemically treated to resist decay in ground-contact applications — useful for posts in direct ground contact
- For above-grade structural timber work, Douglas Fir is a superior aesthetic and structural choice with no chemical concerns
- PT lumber is not typically used for exposed finish timber work due to its appearance and surface quality
