When you hire a roofer to repair a leak, replace shingles or address storm damage, you may expect the work to involve only the visible roofing materials. Sometimes, however, removing the roof covering reveals a problem underneath: the roof decking is rotten, weakened, split or otherwise damaged.

This discovery can change the scope of the project. While it may be frustrating to learn that additional work is needed, replacing damaged decking is an important part of completing a roofing repair correctly.

What Is Roof Decking?

Roof decking, also called roof sheathing, is the structural layer of material installed over your home's roof framing. It creates the relatively solid surface that supports the underlayment and roof covering above it.

Depending on the age and construction of the home, decking may consist of plywood, oriented strand board (OSB) or solid wood planks. Because the decking is underneath the roof surface, homeowners usually cannot tell whether it is in good condition simply by looking at the roof from the ground.

A leak that has existed for an extended period may allow moisture to reach the decking, where it can eventually cause deterioration.

Why Does Damaged Decking Need to Be Replaced?

Replacing damaged decking allows the roofer to establish a sound surface before installing the new roofing materials.

Installing new shingles over deteriorated decking can prevent roofing nails from holding securely, increasing the risk of loose or wind-damaged shingles and subsequent leaks.

How Does a Roofer Discover Rotten Roof Decking?

A roof’s decking is covered by both shingles and underlayment, so roofers typically only see it when removing both layers. Whether damaged decking is exposed during a targeted roof repair depends on the extent of the repair work, but a roof replacement provides an opportunity to inspect the entire roof deck for damage.

Areas around previous leaks, roof penetrations, valleys, flashing and other locations where water may have entered deserve particular attention.

A roofer may find wood that is soft, deteriorated, discolored, split or otherwise unable to provide an appropriate surface for the new roofing system.

Not every dark spot or minor imperfection automatically means an entire section needs to be replaced. The condition of the decking needs to be evaluated to determine whether it remains structurally suitable or requires removal.

Why Can Rotten Decking Make a Roofing Repair Larger?

The visible size of a roof problem does not always represent the full extent of the damage.

For example, a small area of missing or damaged shingles may have allowed water to enter the roofing system. That water can travel beneath the roof covering and affect the decking around the original entry point. Once the roofing materials are removed, the damaged area may turn out to be larger than what was visible from the outside.

This is why a roofing repair can sometimes expand after work begins. The roofer may have initially estimated the project based on visible damage, but removing the roofing materials provides an opportunity to inspect the underlying structure more thoroughly.

If additional damaged decking is discovered, those sections may need to be removed and replaced before the roofing installation can continue.

What Happens When Decking Needs to Be Replaced?

Replacing damaged roof decking can turn a relatively small roof repair into a larger project. Decking is typically installed in sheets, and depending on the location and extent of the damage, a roofer may need to replace an entire sheet or a smaller section that can be properly supported by the roof framing.

New underlayment and shingles must overlap and integrate properly with the existing materials to prevent water from entering around the repair, so some materials surrounding the damaged area may also need to be removed or replaced.

If the discovery changes the original scope of work, your roofing contractor should explain what was found and why the additional work is necessary before proceeding with unexpected costs.

Can You Prevent Roof Decking Damage?

Regular roof inspections and prompt repairs can help reduce the likelihood of moisture reaching and damaging the decking. A small roof leak may seem relatively minor, but allowing water to enter the roofing system repeatedly can lead to more extensive deterioration over time.

After severe weather, it is especially important to have your roof inspected for damage that may not be obvious from the ground.

Schedule a Roof Repair Estimate in Benbrook, TX

Get in touch with Billy Harris Roofing today by calling (817) 249-3338 or (800) 320-6074 to schedule a professional roof inspection and learn more about our roof repair services in Benbrook and throughout the DFW area.