LI,
Got any pics of the deck you are building?? I'd love to see it.
Gav,
When talking about PT Pine, I built a deck last year for $10-12 a sq.ft. Made good money at that price. Honestly, I wouldn't bring up the 'replacement' angle unless the deck is something other than pt pine. Many people build them for $8, and I restore them for $2-3. The only time I'd bring it up is on exotic woods. What I'm really going to start pushing this next year is the environmental aspect of wood restoration, i.e. saying they can triple the life of their wood if they protect it, saving valuable resources. Fences are even worse, you could literally replace the planks on a shadow box fence for what I'd charge to restore it. Makes for a tough sale.
jon