I was writing on a different subject this week, when I was reminded of an inspection that I performed in the summer. Late one evening a past client of mine turns up with a friend in tow, asking if I would please come look at her house. There was a roof leak that was driving her nuts, but no one could find it. I pulled out my tools, and went over to her house.
She explained that she already had called out an HVAC contractor, a roofing company, a plumber, and a general contractor. They found nothing, but they all agreed with her that it had to be a leak from the roof. She had a closet where the rug was soaked, and in another part of the house a carpet was wet. The contractors had checked the various pipes, pans, and shingles, but they found no leak. To truly find a roof leak is difficult. You may find evidence of a trail of water stains on the framing down to the insulation, and then on to the walls in the interior, but I saw none of this. I did find a problem with the framing, and with a vent pipe that was improperly installed, but no moisture. These issues were not mentioned to her by the other contractors.
After crawling through the attic, I looked at the house, specifically the bathrooms. One of the leaks could have been from a lavatory in one bathroom, but the other moist spot could not have been explained by that means. I told the homeowner that I was going to walk around the house. She looked puzzled. If it is a roof leak, why was I going to look at the exterior walls?
Directly outside of the closet wall, I saw that the grading was high. In fact, it was up to the weephole in the brick. The weephole is there to allow moisture to escape from behind the brick. A palm was directing rain water from its leaves to this spot. The wall here was soaked. I walked to the other side of the house to see a brand new patio with beautiful stone pavers. Instead of taking out the old patio, the contractor cemented these stones onto the old patio slab. The new patio was slanted to bring water back towards the house. The new stones happened to also bring the patio up to the weepholes. For two different reasons, the rain from the roof was getting into the house, but not through the roof, rather through the walls. When I pulled back the carpet where the weepholes were, I found moisture stains emanating from the walls. Score one for the inspectors; other contractors zero.
Sometimes a client becomes so fixed on an idea that the contractor who comes out to look at the problem will go along with it. If you are a homeowner, try not to influence the opinion of the worker who is coming out for the repair. State the simple fact without your conjectures. Let them explore the possibilities. In this case, the first guy out might have discovered the source.