Why Solid Decking is Required On New Builds/Re-roofs In Oklahoma

What Is a Solidly Sheathed Deck?

A “solidly sheathed deck” refers to a roof structure that’s covered with continuous panels—usually plywood or oriented strand board (OSB)—without large gaps or spaces. This deck provides a smooth, secure surface for the underlayment and shingles to be fastened to.

In older homes, especially those built before modern roofing codes, roofs were often constructed with spaced plank decking, sometimes called “skip sheathing.” While that may have been acceptable decades ago, it doesn’t meet today’s code standards for asphalt shingles in Oklahoma.

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The Code Requirement

Under IRC Section R905.2, which Oklahoma has adopted with state-specific amendments, asphalt shingles “shall be fastened to solidly sheathed decks.” This means if your home has old plank decking with large gaps, you must install a layer of structural sheathing—like OSB or plywood—before new shingles can go on.

This rule is enforced across the state, including cities like Oklahoma City, Tulsa, Norman, Edmond, and many others. Roofers will check the decking during tear-off and before new shingles are installed to ensure compliance.

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Why Oklahoma Enforces This Rule

1. Better Nail Penetration and Holding Strength

Shingles are only as strong as what they’re attached to. On a solid deck, nails have consistent penetration, creating a secure bond that can withstand Oklahoma’s high wind speeds and severe storms.

On old, spaced plank decks, nails can miss boards entirely or hit areas that don’t provide enough grip. That leads to loose shingles, wind damage, and premature failure—something homeowners and insurance companies want to avoid.

2. Increased Wind Resistance

Oklahoma is known for strong winds, tornado activity, and severe thunderstorms. A roof with poorly secured shingles is vulnerable to uplift, tearing, and blow-offs. A solid deck provides the structural backing needed to meet modern wind uplift ratings and manufacturer installation requirements.

Many shingle manufacturers also require solid decking to honor their product warranties. Without it, homeowners can lose coverage if a storm damages the roof.

3. Improved Water Resistance

Water can be relentless in Oklahoma—whether it’s driving rain from spring storms or snowmelt in the winter. A solid deck provides a flat, even surface for the underlayment, which is your roof’s first line of defense against leaks.

When decking is spaced, underlayment can sag between gaps, creating weak spots where water can pool and eventually seep through. Over time, that can lead to rot, mold, and interior damage.

4. Stronger Structural Support

A solid deck acts like a structural diaphragm, helping distribute loads evenly across the roof. This is especially important in areas with strong wind uplift pressures or where hail and debris impact the surface. It keeps the entire roof system tied together, reducing the risk of partial failure during extreme weather.

5. Energy Efficiency & Insulation Benefits

A continuous deck also helps regulate attic temperatures and improves the home’s energy performance. It minimizes airflow through the roof structure, keeping conditioned air inside and unwanted moisture or hot air outside.

While this isn’t the main reason for the code requirement, it’s a welcome bonus for homeowners looking to lower energy bills in Oklahoma’s hot summers.