Ct, turn on the midwestern boy charm and gentlemanly ask her out. Remember though, if you've just gotten finished working on two attic AH's in the church, you may not quite look or smell your best, so her expressions or responses may not be what you'd like.
The advice on harassment is dead on, seriously. We had a harassment case within our local fire department, where I'm a volunteer member. A lot of us were involved in the investigation, whether just being interviewed or two guys with potential charges being leveled against them. It all proved to be a groundless case thankfully. Still, it makes one realize that there can be a very thin line between just asking for a legitimate date and harassment. It all depends upon the perception of the one who is receiving the invitation.
If she is desirable and seems likely to be interested, I see little harm if asked properly. Should you ask, do so as a gentleman and make certain honorable intentions are being offered. If she says 'no', that is the end of it. While persuing a person of desire who may be playing hard to get can be fun and full of intrigue, in cases of customers or other professional relationships, let it go at NO. When people push the decline is when things can get sticky. Tell her you never do this sort of thing, keep the charm going without seeming a player. If you need an excuse to reenter the premise, come back when in the morning when you look and smell best, try the 'I left a tool', disappear for a few minutes, then reappear with your gratitude and an invitation to coffee, lunch date or other. Remember you're talking about a church, so you better return with a screwdriver or something in your hand!
Don't confuse me with facts, my mind is already made up.