What is the Best Option for Roof Decking in 2024?

Choosing the best option for roof decking or sheathing is one of the most important decisions when installing or replacing a roof.

The roof deck serves as the foundation and surface that all other roofing materials are attached to.

This article will provide a comprehensive overview of the different types of roof decking materials.

It also provide the key factors to consider when selecting decking, and recommendations for identifying the best option for your specific roof.

Table of Contents

Key Takeaways

When selecting optimal decking, carefully evaluate climate, roof type, and budget . Get professional input.
Verify decking specifications meet local codes for structure, fire safety, wind zones, and other standards.
Hire experienced roofing contractors for proper installation of all flashing, fasteners, and accessories required.
Inspect roof sheathing regularly and address any moisture issues, damage, or deterioration promptly. For maximum longevity, invest in quality decking materials suited for your specific roof requirements.

What is Roof Decking?

Roof decking, also known as roof sheathing, is the first layer installed during new roof construction or re-roofing projects.

It is comprised of sheets of material such as plywood, oriented strand board (OSB), metal panels, or gypsum boards that are fastened directly to roof rafters.

The main purpose of roof decking is to provide a flat, even surface for attaching the roof covering materials like shingles, tiles, or metal roofing.

Additionally, roof decking provides structural stability by tying all of the rafters together into a uniformed surface.

Types of roof decking configurations

Solid sheathing – Sheets of decking material laid side-by-side across the entire roof surface with no gaps between sheets. The most common approach.

Open or skip sheathing – Sheets of decking material installed with spaces between each sheet to allow for ventilation.

Other less common roof decking types include plank decking with individual wood boards and various proprietary integrated structural decking systems.

Key Factors Selecting best option for Roof Decking

Choosing the optimal roof decking involves evaluating a number of important factors:

Local Climate and Weather

The climate and weather conditions for the area should influence the decking decision.

In cold northern regions with heavy snow loads, higher strength and insulating decking materials are ideal.

In hot southern climates, materials with better fire resistance and reflectivity may be preferable. Coastal regions with hurricane risks require decking able to withstand high winds and impacts.

Roof Type and Pitch

The roof style and slope must be matched to appropriate decking options.

For instance, low slope or flat roofs require materials with greater resistance to standing water and ponding issues.

roof type and pitch — Roof type and pitch

Steeply pitched roofs require decking with higher shear strength and surface traction. Specialized metal decking may suit unique roof shapes like domes or barrel roofs.

Budget

Decking costs, both material purchase and installation, can vary significantly.

While initial cost is a factor, homeowners should also consider total value gained over the lifespan of the decking. More durable and resilient decking may cost more upfront but save money long-term.

Fire Safety

Roof decking products are assigned fire safety ratings, like Class A, B, or C. Builders must follow local fire codes and ratings required in each jurisdiction.

Areas at high risk of wildfires may require specific fire rated roof assemblies.

Weight and Load Capacity

The weight of decking materials impacts the load on the underlying roof structure. Heavier products like concrete require reinforced framing.

Lighter metal or synthetic decking is easier to retrofit. Load capacity must account for dead loads of the roofing system itself plus live loads like rain, snow, or foot traffic.

Prioritize durability and longevity to maximize your investment and minimize future maintenance costs.

Durability and Longevity

How long decking retains its Durability and Longevity against moisture, UV exposure, pests, and other elements indicates its usable lifespan.

While no roof components last forever, high quality decking can extend replacement cycles by decades.

Best Option for roof decking

Now that we’ve covered the key selection criteria, let’s examine the most prevalent roof decking materials and categorize their relative advantages and limitations:

Plywood Roof Sheathing

Plywood panels for roof decks come in 4×8 or 4×9 sheets, usually at least 5/8” thick. The wood veneer plies are layered at right angles to provide strength.
Used for decades, plywood offers proven performance if installed and flashed properly. Edges need additional waterproofing.
With no knots or voids, plywood provides excellent fastener retention and surface strength for attaching roofing.
Disadvantages include potential for moisture degradation and surface defects if quality is low.

You Can Also Read

What Is Roof Deck Construction: A Great Approach To Design Excellence

Selecting The Best Roof Sheathing For Your Home: A Detailed Guide

Oriented Strand Board (OSB) Roof Sheathing

OSB has surpassed plywood as the leading roof sheathing thanks to lower cost. Manufactured from wood chips and adhesives pressed into mats and layered, it resists warping or delaminating.
Provides adequate strength but higher density means heavier panels. OSB lacks surface integrity of plywood so supports spacing must be closer.
Prone to performance degradation if allowed to get wet. Edges still need moisture barriers.
No natural knots but OSB can crack at fastener locations when subjected to loads.

OSB vs. Plywood Comparison

OSB	Plywood
Very cost effective	Higher cost per panel
Higher density, heavier panels	Lower density, lighter weight
More prone to swelling and rot if exposed to moisture	More resistant to moisture degradation
No natural knots but fastener cracking potential	Contains some knots but excellent fastener retention

When selecting roof decking, consider your specific needs and priorities in terms of strength, durability, fire resistance, insulation, weight, and cost.

Metal Roof Decking

Steel and aluminum roof deck panels offer high strength-to-weight ratios. Very lightweight but energy transfers across entire surface.
Metal deck installs over supports with screws, clips, buttons, or welds. Provides excellent spanning capacity.
Factory finished metal panels resist weathering. Limitations include heat conduction and potential for dents from hail impacts.
Avoid combining dissimilar metals during installation. Higher cost but long lifespan.

You Can Also Read:

What Is Metal Roof Decking: A Complete 7-Step Guide To Durable Material

Poured Structural Concrete Roof Decks

Concrete creates a monolithic, continuous structural roof deck when poured over forms and rebar grids. Provides very high compressive and shear strength.
Outstanding fire resistance and insulating value. Ability to mold into complex geometries.
Downsides include high weight requiring reinforced structural framing and potential for shrinkage cracks over time.
Higher installation cost but extremely durable and effective.

Gypsum and Fiber Panel Roof Sheathing

Factory made gypsum boards and treated fiber panels offer affordable synthetic sheathing alternatives to wood.
Limitations include lower shear strength, minimal insulation value, and moisture vulnerability if exposed. Better for interior roof assemblies.
Provides roof deck continuity but requires supplementation with higher strength structural layers.
Useful for inhabitable attic spaces below roofline needing fire barriers.

Roof Decking Cost Comparison Table

Material	Typical Cost per 4×8 Sheet
OSB	$9 – $18
Plywood	$15 – $30
Steel Deck	$1.20 – $2.50 per sq. ft.
Aluminum Deck	$3 – $5 per sq. ft.
Concrete	$8 – $12 per sq. ft.
Fiberboard	$7 – $10
Gypsum	$10 – $14

Conclusion

Choosing the best roof decking involves research and expert consultation to match the optimal material and construction method to your roof’s unique specifications, local building codes, budget, and expected lifespan.

With appropriate decking properly installed, your roof will provide reliable performance for decades to come.

FAQ’s

What’s the best roof deck?

The best roof decking provides structural integrity, durability, and weather resistance at a reasonable cost. 5/8” tongue-and-groove plywood and oriented strand board (OSB) are top choices for pitched roofs. Engineered wood is exceptionally strong for flat roof applications.

Is it better to use plywood or OSB on a roof?

Plywood edges out OSB for roof decking when strength is the top priority. However, OSB continues gaining acceptance by codes and offers structural capabilities at lower cost. Both should carry exposure durability ratings for weather protection.

What is the recommended roof sheathing?

Plywood and OSB sheathing rated for roof application offer durable protection from the elements at affordable prices. Polyisocyanurate or XPS foam sheathing enhances insulation. Fiberboard, metal panels or underlayments boost severe weather performance.

What is the best material for decking on a flat roof?

Plywood provides a sturdy, economical substrate but engineered wood or plastic lumber excel on flat roofs by limiting expansion and contraction stresses.

Are rooftop decks worth it?

For city dwellings short on outdoor space, rooftop decks create enjoyable relaxation and entertainment zones. Just account for the complexities of reinforcing the roof structure to handle deck loading.