When roof repairs don't make a leak go away the first time, it's usually because there's another cause for it, one that isn't even necessarily related to the first leak. There are several possibilities, so here's what to look for.
Clogged gutters hold in moisture instead of letting it drain like it's supposed to. If the clog is serious, this could cause water to pool on your roof. While your roofing material is designed to let rain flow off, it's not as effective at keeping out stagnant water. Pooling water can easily get under shingles and underlayment and seep into your house. Double-check your gutters and downspouts; even if the gutters themselves look clean, there could be clogs in harder-to-spot areas.
Ice dams occur when uneven insulation creates pockets of warmth against your roof. Ice and snow on your roof will melt in these areas but won't be able to flow off your roof. Much like pooling water created by clogged gutters, ice dams can hold pockets of water up against your roof and make it much easier for water to get in even if your roofing material is in good condition. Ask your roofer to inspect your attic insulation just in case.
Damage Beneath Shingles
Sometimes the problem can lie beneath your outermost roofing material. If shingles or tiles are repaired but you're still having leaking issues, the issue could be with the underlayment or flashing, or even with the roof structure itself. This can sometimes be hard to spot given that such damage will often be under material that can't easily be removed, but your roofing professional can inspect your attic area for you to check for signs of persistent dampness or damage.
In rarer cases, the movements of your house can sometimes cause small cracks or tears in your roof. This will typically happen if the foundation shifts, which subsequently causes the frame of the house to shift. This is a problem that can build on itself from previous roof issues. For example, improperly installed or maintained gutters can result in rainwater causing slow but steady damage to the area around your home's foundation, making it more likely for shifting to occur. If water tends to pool around the outside of your house when it rains, even if only in certain areas, it might be worth asking for a foundation inspection as you get your leak taken care of.
It's Coming From Elsewhere
It's also possible that the source of the leak isn't your roof at all. One alternate explanation is your house's siding. If water gets behind your siding it can display many of the same signs, and show up in many of the same places, as water from a roof leak. These issues can be related, but don't necessarily have to be. If you suspect this is a possibility, ask your roofer to check your house's siding as well, especially if there's any chance your previous leak could have let water behind the siding as well as into the rest of your home.
For more information on roofing leaks, contact a company near you.