Catholic Wedding Q&A
Can we have our wedding someplace other than a church building?
In most cases, Catholics are required to be married in a Catholic church building (see Canon 1118). There are some exceptions. When a Catholic marries someone who is not Catholic, the Catholic party may request permission from the local bishop to celebrate the wedding at the other person's place of worship. Because Church law states that a wedding may be held in "some other suitable place" besides a Catholic church, it is technically possible that the local bishop might allow outdoor weddings, but few do.
No one would argue against the beauty of a natural setting; after all, creation reveals the presence of the Creator in a powerful way. But Catholics remember that Jesus Christ promised to continue to be present whenever his friends gathered in his name. The church building is the "house" in which the followers of Jesus do this on a regular basis to celebrate weddings and funerals and baptisms and confirmations and reconciliations and anointings of the sick—in short, all the most important events of their lives. For Catholics, it makes sense to begin a new household in this sacred house. Doing so symbolizes the new family's connection with the wider community of believers—not only those present at the wedding, but also all the parishioners who gather in that space, and ultimately, the universal Church.
For more information
Must Catholics Have Their Wedding in a Church?
An excellent article that explores this issue in more detail, from BustedHalo.com.