The direction of a material
Wood has a direction. Fibres run predominantly along the length of a piece, while end grain exposes their ends. This affects how a piece takes up moisture and how its surface appears. On an accessible sample, compare the end with the long face rather than treating the material as uniformly patterned.
Growth rings can suggest how a board was cut, but a small photograph is not a reliable species identification. Stain, finish, weathering, and lighting can all disguise color. Record grain direction and visible geometry before reaching for a name.
Watch the meeting with water
In an exterior assembly, examine where horizontal faces, cut ends, and fixings meet. Is water encouraged to drain? Can air reach the back of a piece? Are there sheltered pockets that could stay damp? These are useful questions even when the hidden layers remain unknown.
Do not probe, scrape, or remove material from a building during an observation walk. A soft-looking area or a dark stain needs contextual assessment, not an improvised test by a passerby. Photograph from permitted positions and record uncertainty explicitly.
Specify questions, not guesses
For a material sample, write down its source, stated species if supplied, finish, and intended location. Keep the label with the sample. If the information is unknown, say so. A confident-looking unlabeled block is less useful than a modest sample with a clear record.
Questions for a supplier or designer might include expected movement, maintenance, fixing method, and replacement access. Answers depend on the particular product, assembly, and environment. A reference notebook can organize those answers; it cannot replace them.