Although not the most common reason your porch roof leaks, damaged roofing material might be the most obvious. When you begin inspecting your porch roof for potential leak causes, damaged roofing material should be easy to spot. If something has fallen on the roof, like a tree limb, you may see exactly where the problem is. Damaged shingles or other roofing materials can certainly allow water to penetrate the roof and spill into the porch area below. If the damage isn’t so obvious, you may have to remove some roofing, after the rain of course, and locate the exact spot where the water is getting through. Once the top layer is removed, you should see the water stains on the underside of the roof sheathing.
Far more commonly you’ll find that the flashing on your porch roof is the reason you have a leak. Over time the flashing can get corroded or damaged by the environment. The flashing may even have been installed incorrectly. If you locate the spot where the flashing is letting water through, you may have to remove some roofing and siding around the problem area and replace it, making sure it is installed the proper way.
If you haven't cleaned out your gutters in a long time, your leak may simply be water spilling over clogged rain gutters. Even if you take good care of your gutters, you may find that the porch roof leak is located at the point where the roof meets the gutters. Water will channel behind the gutters and drip onto the porch below, possibly running down the wall of the house if the gutters are not attached properly to the fascia board, which is the board at the end of the rafters that the gutter attaches to. The gutters may also have been installed without enough roof overhang to drip the rain into them.
If you are looking for a quick fix, you may be tempted to phone a handyman to slop some tar on your roof to patch it, which is not a good idea and should be avoided if at all possible. The reason it is a bad idea is because it is very temporary if it works at all. Also, the tar seals in any moisture from the leak into the roofing materials below it, which can cause corrosion and age your home faster than it should.