Everything You Need to Know About Roof Decking

Sloped roofing systems wouldn’t be complete without roof decking. In this blog, the roofing contractors at Henderson Roofing discuss everything you need to know about this essential roofing component.

What Is Roof Decking?

Roof decking, also known as roof sheathing or simply, decking, fills the spaces between trusses and joists. It provides a flat plane where components such as underlayment (felts) and shingles can be fastened to. Insulation is typically installed on its underside. On metal roofs, decking absorbs vibrations and makes the roof quieter.

Roof Decking Comes In Different Types

There are several types of roof decking, which gives homeowners and builders more flexibility when choosing among various roof replacement options.

1. OSB – Oriented strand board, or OSB is the most common type of roof decking, thanks to its relatively low cost, durability, and ready availability. OSB is made of interwoven wood strands that are bonded with adhesive.
2. Plywood — Plywood is another popular and durable decking option. The installation method is the same as OSB, with individual boards spaced accordingly to allow for thermal expansion and contraction.
3. Tongue and Groove — Tongue and groove decking is made of two-by-six boards, with a “tongue” on one edge that fits into the “groove” on another board’s edge. This type of decking is typically seen on homes that do not have a ceiling. The boards, when seen from indoors, add an aesthetic element.
4. Plank Sheathing — Plank sheathing is typically seen on homes built before 1970. Instead of a solid surface, roofing material such as wood shingles are installed on planks spaced about one and half inches apart.

Decking Doesn’t Always Need to be Replaced

A typical roof replacement process involves stripping the old roof down to the roof deck. Most types of decking are usually good for two roof installations before it’s due for replacement, assuming it’s not damaged by moisture infiltration. A third installation using the same roof decking is generally not recommended, as it would have too many holes from fasteners to ensure a secure installation.

Your roofing contractor will determine during an initial inspection whether the decking will be kept or replaced. If you intend to switch to another type of roofing—from cedar to asphalt shingles, for instance—the decking will be replaced to match the new roof’s requirements.

Henderson Roofing is your leading provider of roofing services, including roof leak repair. Give us a call at (401) 615-2224 and (860) 415-4055 or fill out our contact form to schedule an appointment.