Roof decking (also called roof sheathing) is the most important part of your roof system. It’s the foundation of your underlayment and shingles. Virtually every part of your roof is fastened in some way to your roof decking or sheathing, including the flashing, drip edge, fascia, gutters, skylights, etc. But like everything else, roof decking won’t last forever.
If you’ve ever seen a sagging roof, you probably saw a house with rotted roof decking or sheathing. For most homeowners, roof sagging is a clear sign of decay. However, structural issues beneath your shingles may not always be so obvious, and fixing an issue with your roof decking or sheathing won’t be cheap. In some cases, it may add upwards of $300 in material costs alone to the average roof replacement bill.
But there’s more to learn about roof decking installation and maintenance if you want to ensure your roofing investment protects your home as long as possible. Let’s dive into the details that homeowners need to know to take proper care of their roof decking or sheathing.
While some roofers prefer one term over another, roof decking and sheathing are the same thing. Both terms refer to the flat wood boards that form the base of your entire roof. Roof decking (or sheathing) is secured across the trusses and joists of your home. When a new roof is installed, roofers will nail or staple your underlayment and shingles directly to the decking (or sheathing).
Originally, before the mass availability of plywood, roof decking was made of planks (namely 1×6 or 1×8 boards, laid across the full length of the roof to cover it completely). Today, plank decking isn’t used as much anymore. However some older homes may still have original plank decking and some homeowners may install it as a deliberate choice. That said, plank decking is very expensive and can be quite susceptible to leaks between boards.
Because of this, homeowners choose either OSB (oriented strand board) or plywood when building a new home or replacing a roof.
Here’s a look at each type of material:
Several things can damage your roof decking, including water, hail, heat damage, fungus, termites, and even falling trees. Unfortunately, not every type of damage can be spotted from the ground. You may require the help of a professional roofer to diagnose the true problem. That said, here are some ways you can tell if your roof decking or sheathing needs to be replaced.
The quickest way to tell whether or not your roof decking needs to be replaced is to inspect your roof. As a homeowner, you may not be able to safely climb onto your roof or properly inspect it for damage without a professional eye. But you will likely be able to inspect your ceiling and attic.
Look out for leaks or signs of deterioration. If your attic is unfinished, you should be able to look at the underside of the roof decking directly for signs of damage or rot. If you are able to climb a ladder safely, you can also survey your roof from the edge to look for sagging or other concerning signs of damage.
In any case, it’s always best to have your roof inspected by a trusted roofing expert. These professionals have an eye for roof damage and can recommend the best course of action to bring your roof back up to code.
Roof damage is usually evident. However, some forms of damage are harder to spot than others. In some cases, you may not notice them until your roofing materials are completely removed during the replacement process.
Here are some signs to check for:
If your roof decking or sheathing isn’t deteriorated or rotted in any way, you may not technically need to replace it just yet. If your roof is installed properly in the first place, the roof decking should last nearly 100 years. However, if your roof wasn’t installed or maintained correctly, rain, wind, heat, snow, and other types of weather may shorten its lifespan.
Roofing materials play a huge role in protecting your roof decking. For example, synthetic shingles are rated to last between 30 and 50 years on average. If you have these installed with new decking, it will likely protect it for just as long (if not longer). On the other hand, asphalt shingles (while more affordable) are only rated to last about 20 – 30 years and may offer less protection for your roof decking in terms of longevity.
If for some reason your roof decking is only projected to last another decade, you may want to proactively replace it. In many cases, waiting too long to replace your roof may cause major issues and expensive repairs down the line. If your roof system isn’t up to code, your home may become vulnerable to leaks and water damage.
With that in mind, it may be a good idea to replace your roof decking somewhat early to make sure the rest of your home is protected from the elements. Doing this just before you decide to sell your home may also add tangible resale value to your property.
If your roof decking or sheathing needs replaced due to extensive damage or rot, you will need to replace the entire roof. That means adding new shingles and underlayment along with new decking/sheathing. This may cause the project to take longer than the initial estimate.
Here’s how our replacement process at Baltic looks when roof decking is included in the project:
To make sure you get the most life out of your new roof, it’s important to make sure your decking or sheathing is properly protected. While it’s true that roof decking naturally decays over time, there are ways to preserve the materials so that they last longer in general.
Here are a few best practices to help extend the life of your roof decking/sheathing:
Roof maintenance is an incredibly important part of taking care of your roof. That’s why some professional roofing companies offer roof maintenance programs. In exchange for a monthly or yearly fee, the roofing company will regularly inspect your roof and repair any damaged areas such as cracked singles, broken flashing, or torn sealant. It’s important to clean off any debris that could cause water drainage or clog your gutters. When possible, removing snow from your roof can also help to prevent ice dams.
Keeping gutters clean is essential to ensuring proper water runoff. To protect your roof decking from water damage, you want to be sure that water has a clear, controlled path away from your home. If something gets lodged in the gutters, it may cause water to run back onto your roof, leak underneath damaged shingles, or run straight off the edge of the roof to eventually erode your foundation.
In Illinois, ice and water shield membrane is mandatory with any roof replacement project. It’s a great way to protect your home from harsh winter weather no matter its age.
Typically, these large pieces of specialized underlayment are installed in the same places you might find roof flashing. You may use ice and water shields to trim eaves and rake edges, line roof valleys, or seal gaps around skylights, chimneys, and roof vents.
Especially in the Midwest, ice and water shield is an essential part of a roofing system. It can help keep your roof decking safe from ice dams, rain, and snow that may melt through damaged shingles.
Roof flashing helps to ensure proper water runoff in multiple areas on your roof. Most of the time, metal flashing is installed near roof joints near sidewalls, in roof valleys, and around other protrusions on your roof. Without flashing, water could run between roof joints and gaps between pieces of roof decking.
Drip edge is a specific type of flashing that protects your roof edges, as well as prevents water from running back against flashing or underneath your shingles onto your roof decking. It is typically installed at the eaves or rake edges of your roof to direct water into the gutters or away from the foundation. Without proper drip edge flashing, water may quickly ruin your roof decking or other key structural elements of your home.
Roof decking/sheathing should not be ignored. If you’re in need of a full roof replacement, it’s important to know when and if you should replace your roof decking so that you can have an informed conversation with your roofing contractor. It’s also important to understand your roof decking so that you can regularly inspect your roof for signs of damage.
That said, you may not always be able to tell if your roof decking is in good shape yourself. For peace of mind, it’s best to have a professional roofer diagnose the true condition of your roof decking/sheathing.
But how do you know your roofer is telling you the truth during your inspection? At Baltic Roofing, we’re proudly local to the Chicagoland area and our reputation for honest roofing work and great workmanship means a lot to us. That’s why we’re committed to being your trusted, local choice for high-quality roofing.
If you hire Baltic Roofing for a roof inspection, we’ll look at every part of your roof in detail and report back to you with an honest assessment. We’ll only recommend what’s necessary to bring your roof back up to code and today’s standards..
Want to know if your roof decking (or sheathing) is still in good shape? Call us today to schedule a roof inspection.
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