All too often, homeowners put off a much-needed roof replacement because the shingles look fine. Unfortunately, damage to a roof may not be immediately obvious. Your roof is made up of three main layers: the decking, which is typically made of plywood and forms the roof base, the underlayment, which creates a water barrier on top of the decking, and the shingles, which create the main upper weather barrier. If the decking fails, then the rest of your roof can't keep your home dry. The following are signs of decking issues.
1. Moisture Damage in the Attic
Water that makes it through the decking ends up in your attic, so a quick visit upstairs can often be the quickest way to determine the state of your roof. In the early stages of damage, you may only see a few water spots or signs of discoloration on the underside of the decking. As the damage increases and the leaks worsen, the insulation can get wet and begin to mold. In the most severe cases, the decking will begin to rot. You will be able to easily push your fingernail or a screwdriver head into the saturated wood. Musty odors in the attic are another symptom of leaks and decking issues.
2. Spongy Feel On the Roof Exterior
If you ever walk on your roof, such as to install holiday lights, then you are likely aware that the surface feels solid underfoot. If moisture gets into the decking, the wood fibers swell. Over time, these swollen fibers break down and the roof feels spongy underfoot if you go up on it. First and foremost, get off the roof if you notice this sponginess. It's a sign of rot, and the decking may not be able to hold your weight.
3. Sagging Ridges or Roof Sections
The same moisture in the decking that leads to rot and sponginess can also cause the roof to sag under its own weight. Sagging is typically easy to spot from the ground. Often, it shows first in the peaks and ridgelines, which will develop obvious bows or dips along their length. You may also notice sagging on certain sections of the roof, particularly on low-pitched roofs, as water may collect in the sagging section when it rains. A sagging roof may be at imminent risk of collapsing, so a repair is required.
If you suspect decking damage, you need to contact a residential roofing company immediately to discuss getting a roof replacement.