Types of Roof Decking Damage
Roof decking, or sheathing, is the structural foundation of your roofing system. Learn more about the types of damage that can affect it.
Roof decking, or sheathing, is the structural foundation of your roofing system. Learn more about the types of damage that can affect it.
Roof decking, sometimes called roof sheathing, is the structural foundation and base layer that supports the roof underlayment and shingles. It’s commonly made of oriented strand board, plywood, or wood planks and nailed directly to the roof’s rafters or trusses to ensure even weight distribution and overall stability.
Because wood decking serves as the structural foundation and anchor point for your roofing system, it must remain in good condition at all times. If damage occurs, it can lead to structural failure, and we know you like having a roof over your head.
Although roofing systems are designed to withstand the elements, they can and will fail over time, especially if you live in an area prone to heavy wind, hail, and frequent rainfall, all of which eventually take a toll on your system, especially if there are already existing ventilation problems.
In this article, we’ll review some of the most common types of roof decking damage we see during our exterior and interior inspections.
Decking is made from wood, so it isn’t resistant to moisture. That’s why it’s protected by an ice and water shield, underlayment, and shingles.
Rot and decay usually result from poor attic ventilation, although they can also be caused by flashing damage and penetrations in the shingles. If moisture builds up, it leads to heavy condensation on the wood, trapping it in the decking beneath the shingles. Some common signs of rotting or decaying decking include:
Rot and decay issues are resolved by replacing the compromised boards and addressing the underlying issue, which, as we mentioned before, is usually poor attic ventilation. However, sometimes the cause is roof leaks from impact damage.
Delamination occurs when the wooden layers that make up the sheathing (if the decking is made from plywood) separate and come apart, weakening the wood’s structural strength and jeopardizing its ability to hold nails securely and support the weight of the roof system. OSB decking has compressed strands and can swell and separate.
Delamination is commonly caused by excessive moisture and high humidity, which weakens the wood. Excessive moisture and humidity usually result from poor ventilation and inadequate insulation.
Signs of delamination include:
Sagging is when the roof decking bends or sinks. Sagging commonly occurs when the decking loses strength, with obvious aesthetic signs such as dips or wavy areas in the roof.
Roof decking commonly sags due to:
Pest issues are actually quite important to resolve immediately. If your roof is damaged from animals or insects, like ants, termites, mice, birds, raccoons (like Jimothy!), and squirrels, who love snacking on and burrowing into wood, your insurance company is unlikely to pay for any repairs. Always check your policy, but pest damage is usually a named exclusion.
Carpenter ants and rodents can chew away at your roof decking, while raccoons and birds damage sheathing to make nests and habitats. When pests infiltrate your roof, it increases your risk of water damage and structural degradation over time.
Common signs to look out for:
Roof decking is covered by the underlayment and shingles, so identifying damage isn’t always easy to spot from the exterior, but you can notice signs from your attic. We always recommend that homeowners check their attic every now and then for potential mold, condensation, or blocked vents. If humidity is high or there are grease spots in the attic, your bathroom and kitchen vents are likely directing into your attic rather than outside.
On the roof, look for curling shingles, visible sagging, or soft or spongy spots. Unfortunately, if it’s at this stage, wood rot and decay are almost always going to be present and require decking repairs.
During the winter, look for ice damming or uneven snowmelt on the roof. Ice damming isn’t normal, and heat tape won’t fix the problem because it doesn’t address the underlying issue. Ice dams are caused by warm air leaking from your living space into the attic, insufficient insulation, and poor ventilation.
Replacing roof decking is an invasive process that involves removing roofing materials from the affected areas, then cutting out and replacing the boards, so being proactive is always the best method.
If you’re not familiar with your roofing system, whether it’s because you’ve just moved in or you’re unsure when it was last inspected, schedule an assessment. That’s the best prevention method. A professional can quickly identify ventilation blockages, humidity and condensation problems, and insulation issues.
As mentioned earlier, try to get up into your attic a few times a year to check for condensation and mold. And after any inclement weather event, perform a ground-up inspection of your roof.
Beyond inspections, we recommend:
If you don’t know when your roof was last inspected, or you’ve noticed any of the issues we talked about in this article, schedule a free inspection with L&S Home Improvements today.
We perform exterior roof and interior attic inspections to identify ventilation and insulation problems and determine the condition of your entire roofing system. When you work with us, you can expect honest, unbiased advice. We are also homeowners and understand the (sometimes) disadvantages of owning a home! We want the most cost-effective solution for you, and that’s what we’ll offer.
Our licensed and insured team has been repairing and replacing roofs across Macomb, Oakland, and Wayne Counties for decades. Visit our website to learn more about how we help homeowners like you, or contact us today to get started with a free, no-obligation inspection.
