Proper Wrapping To the Editor: Thank you for the insights into the proper way to install housewrap ("Wrapping the House: Do's & Don'ts, 3/00). I can see that I have made a few mistakes, but now I have no doubt about the proper way to tackle flashing and wrapping details. We do have a brake and use it. Al Brand Valhalla, N.Y. Competing With the Big Boxes To the Editor: I enjoyed Paul Eldrenkamp's article on charging for estimates (Strictly Business, 3/00). Although I agree that we should not charge for estimates, I think the dialogue about what is "included" in a package of services is important. I have observed an "unbundling" trend in services from lawyering to home improvement. Some lawyers