Be clear about your outcome
When our church led the way in building the new $3-million community center in our town, we did not expect the outcome to be new members for our church. We did expect the community center to become a gathering place for the community.
When we helped start the local Boys and Girls Club by hosting them in our building, we didn't expect to get new members for our church. We did expect to provide a safe after-school program for underserved kids.
When we worked to establish a community music school that is headquartered at our church, we didn't expect it to increase membership either. We did expect it to provide quality music instruction for children.
When we partnered with artists and educators in our community to start Soundcheck, the monthly teen open mic night, we didn't expect it to bring new members to our church. We did expect Soundcheck to be a venue for artistic expression, and to increase arts awareness in our town.
Because we understood going in to each of these projects that there probably would not be an immediate payoff for our church in increased membership, our congregation was not disappointed when no new members joined from any of those programs.
Be clear about your desired outcome before you start a project. Don't try to sell every project as a membership project. Churches can be on mission to transform their communities, too.