In most cases, minor roof damage can simply be repaired–you don’t need to replace the entire roof. However, the roof deck is one of the few parts of the roof that can’t be repaired, only replaced. In today’s post, Mass-Tech Roofing and Building Co. shares a look at roof decks and explains why repairs are not an option for this crucial roofing component.
The roof deck, also known as decking or sheathing, is the layer of plywood or composite that covers the upper roof framing. It is the flat surface that the other parts of the roof, including moisture barriers and the outer roofing material, are fastened to. The side of the roof deck that faces the attic can be filled with cellulose-based or expanding foam insulation. A well-maintained and properly installed roof deck can last for decades and may even be used for a second shingle installation.
The decking is protected from most types of roofing damage, thanks to the outer roofing material and the moisture barriers underneath. There are two ways a roof deck can be damaged, both of which will require a new roof installation: severe impact caused by a large falling object, such as a large tree branch during a storm, or moisture infiltration. The latter can be caused by punctures on the roofing surface or trapped moisture in the attic.
The problem with damage caused by moisture infiltration is that it’s easy to miss unless you regularly inspect the attic from the inside. Signs that point to damage to the roof deck include water stains on the trusses, rafters or the decking material itself if not covered with insulation. Clumps on the insulation and rusty streaks from nail heads also indicate contact with moisture.
Unfortunately, damaged decking cannot be repaired without a partial or full roof teardown. The roof deck is considered a part of the roof’s support structure, which makes spot repairs impractical. This highlights the importance of components like underlayment, moisture barriers and flashing — they protect the roofing structure from damage caused by moisture infiltration. The best way to protect the roof deck from damage is to invest in quality roofing materials and work with experienced roofing contractors.