Creating communities / relationships.

I've been thinking hard about how to best create lasting relationships with customers. Recently I had dinner with a friend who seems to read endless blogs about marketing. My friend started talking about building a community around our brand. My initial reaction was it seems impossible to create communities around a roofing company or custom home builder. So I started looking into his ideas and reading up on inbound marketing. What do you guys think about building these communities around your brand and how do you market to existing customers in such a way to foster relationships that are lasting. While we do repeat business for some of our customers I feel we are loosing lots of opportunity with our roofing customers because we rarely ever hear from them again after we finish the job and get paid. Any ideas and insight is greatly appreciated.