You see some shingles have come off, and you spot the water stain on a ceiling, so it is easy to make the guess that water leaked through the roof. Well, you may be right, but there are other possibilities. Water does not always come straight down, especially during high winds. If you have read other posts here, you may feel that I am repeating myself, but I wanted to have some common causes in one post for those of you trying to find out what is happening in your home after the storm.
At my first inspection after the storm, I found a wet spot in the corner of an exterior wall and a first floor ceiling. The second floor was dry in the area above it. When examining the attic, I found that the siding had thin cracks which allowed water to flow in and down to the first floor through the wall cavity. I provide this an example to show that a roof is not always the culprit.
The only true way to know where the water is entering the home is to be looking around during a storm. With the sunny weather we are now having, you have to look at some areas to make a guess. Here are some places to check:
In the attic- look for signs on the sheathing under the roof for wet spots or spots that are discolored. If it is on the sheathing, then it is likely to be a problem with the shingles. Vents can have small holes which can let a good amount of rain into the house. Damaged vents can have their flashing damaged . The flashing around these vents is the piece which prevents water from entering the house. If you have a roof which has two roof lines at different heights, check the corner areas; water can build up there. Roof caulk is needed on nail heads or around flashing which is leaking. Tarps would be needed for damaged shingle areas, until repaired.
Exterior walls- expansion joints, trim around windows and doors, and corner joints all need to be properly caulked. If the caulking is missing or cracking, this can allow water penetration into the wall. Any cracks in the exterior wall can trap rain water, which then flows into the house. Look for cracks in stucco, mortar joints for bricks, or in masonry veneers. For wood or aluminum style sidings, you need to look for gaps in the siding. The solution is to caulk all of these with a door and window caulk.
When you do not notice a problem in those locations- you may want to consider if the leak is new. I have seen plumbing leaks in walls were pipes are running. Water condensate on refrigerant lines for the air conditioning system, which caused ceiling stains. Also on the air conditioning, safety pans can overflow.
I hope this gives you some ideas of where to look, so you will know which contractor to call out for repairs. Caulking is simple enough for many homeowners. Ask at your local hardware store, and they will set you up with a caulking gun and the right tubes of caulk.