I think you can definitely let them know when you apply that you want to not have them contact your current employer unless they are making an offer. This is a fair thing to request. I also would love to talk to you about the builder you are working with. Can you shoot me an email: Allan@allandubon.com
Sarah, I often work with people looking to move out of their current employment into a different venue and many are facing the same dilemma as you. You might have to let potential employers know that you wish to give your current employer notice yourself and that you request them not to be contacted, as Allan mentioned. I always suggest that my client have a "deadline" in mind when they will realize they are ready to talk to their current employer about the move.
Certainly if you are merely looking, that deadline is not concrete, but realize that word will get out as people in similar industries tend to have friendships, contacts even via spouses and sooner or later your investigation will be known. I think checking out what's available that interests you quickly and with as many potential employers is a good idea and then perhaps return to your current employer and be honest about your decision to move on.