3 Signs That Your Roof's Underlayment May Be Damaged

The underlayment on your roof provides a secondary barrier against water leaking into your home. It's a waterproof barrier that's attached directly to the roofing deck when a roof is installed. The shingles, tiles, or metal panels on a roof protect the underlayment from being damaged by heat, wind, sunlight, and falling tree branches.

Despite being protected by the roof above it, the underlayment can still be damaged. Unfortunately, it's often difficult to tell when there's a hole in your underlayment since it's covered and hidden by your roof. If there's a hole in the underlayment, water and moisture will start to damage your roof deck, and this can lead to water damage in your attic. To learn three signs that your underlayment may be damaged and letting water into your home, read on.

1. Leaks in Your Attic

When your underlayment is damaged, the first sign is typically a leak in your attic. When the roof deck becomes saturated with water due to a damaged underlayment, some of the water will slowly drip down into the attic below it, resulting in a very slow leak. You'll see water stains on the ceiling or walls, and you may smell mold growing in your attic due to moisture intrusion.

2. Sagging Roofline

Another sign that your underlayment may be damaged is a sagging roof. When the roof deck becomes saturated with water, it will start to rot. A rotting roof deck isn't as strong as one that's undamaged, so it will begin to sag under the weight of the roof above it. You'll notice that parts of your roof seem sunken as the roof deck slowly collapses because of the weight. This is a serious problem that needs to be fixed by a roofing contractor immediately, as your roof may eventually collapse into your attic if the roof deck entirely rots away.

3. Mold on Your Roof Deck

If you smell mold when you're outside your home and can't find out where it's coming from, it may be coming from your roof. Roof decks are made from either plywood or oriented strand board, and mold can grow on both types. When the roof deck becomes saturated with water, it turns into a perfect breeding ground for mold. Mold can eat the wood fibers in the roof deck, and it's also kept dark and moist by the roof above it shielding it from the sun.

A damaged underlayment needs to be replaced as soon as possible in order to prevent damage to your roof deck. If you think that your roof's underlayment may have a hole in it, call a roofing contractor and have it inspected. If you wait until your roof deck starts to rot away, the cost to repair your roof will be much higher since you'll need to tear off the rotted roof deck and replace it as well. Calling a roofing contractor to repair the underlayment will limit the damage along with the cost to fix your roof.