Inspect what will carry the deck
Footings, posts, beams, joists, connections and lateral stability form the load path. A new composite surface does not make weak or decayed framing sound. Have the existing structure assessed for condition and suitability for the proposed layout.
Check the house connection and water protection, ground conditions, signs of movement and the way stairs and guard posts attach. Do not diagnose structural capacity from a photograph alone.
Design for the actual site and use
Support spacing and foundation design depend on the product, layout, local requirements and loads. Heavy features, raised decks and unusual sites may need professional design. Snow, occupancy and concentrated loads cannot be reduced to one national span table on this website.
Resolve permits and utility locating before excavation. Keep inspection access available as the work proceeds.
Make structural responsibility explicit
- Who inspects and designs the structure?
- Which repairs, footings and connections are included?
- Who obtains permits and books inspections?
- How will concealed problems change the scope?
Compare these answers alongside the surface-board quotation.