Q: What things should I look for when I inspect my roof?
Here are four things to look for on the inside, from up in the attic:
- Places where the roof deck is sagging
- Signs of water damage or leaking
- Dark spots and trails on the wood
- Wet spots on the drywall that forms the floor of the attic
- Outside light showing through the roof boards.
When you take a look at the exterior of the roof, pay attention to such things as damaged flashing, missing shingles, curling, blistering, buckling, rotting, and algae growth (which occurs most often in humid climates and appears as dark or greenish stains on the shingles).
- Visually inspect your roof for cracked, torn, bald, or missing shingles.
- Scan the roof for loose material or wear around chimneys, vents, pipes, or other penetrations.
- Watch out for an excessive amount of shingle granules (they look like large grains of sand) in the gutters -- this is a sign of advanced wear.
- Check for signs of moisture, rot, or mold. Note that wet spots may not be directly under your faulty shingle; water can travel down to its lowest spot before it drips. Mold, fungi, and bacteria can grow quickly -- within 24 to 48 hours of a water-related problem.
- Examine the drainage, and make sure gutters and downspouts are securely attached. Also ensure all drains are open and allow water to exit, and all gutters and downspouts are free of debris.
- Check that all bath, kitchen, and dryer vents go entirely outside of your home, not just into the attic space.
Q: When do I need a tear-off as opposed to an overlay? ie. when is it OK to put new shingles on top of the old ones?
If you have one layer of shingles on your roof now, you can have one more layer for a total of 2 layers. It is much less work, faster, and less expensive to do an overlay as opposed to a tear-off. When done properly, an overlay is just as good and you cannot tell it's an overlay.