Structures that add genuinely usable floor area (a sunroom, or a canopy over an existing deck) tend to add more perceived value than purely decorative additions.
What matters for resale
- Quality of materials and a documented warranty (buyers and valuers both look for this).
- Whether consent was obtained where required - an unconsented structure can complicate a sale.
- How well it integrates with the existing house, not just the deck.

