
Owning a home is one of the most challenging, yet rewarding responsibilities a person can have. You get the chance to establish a sanctuary for you and your family that provides the protection and comfort you desire. However, this can all be put at risk when you begin to notice issues with your roof such as a couple of wet spots on your ceiling. This may be your first home and may have never even looked at a roof’s foundation before let alone knowing where to begin. You go up to your attic to investigate, and come upon a distinct musty smell of mold. Signs would point to a roof leak, and one of the main causes usually would be roof rotting or roof corrosion if you own a metal roof. What do you do? You may not be an expert in roof contracting, but that is why certified experts like us at Infinite Roofing are here to help you get back to living with the protection and comfort you deserve.
What is Roof Decking?
When talking about roof rotting, we are talking about the roof decking or sheathing of the home. The roof decking plays a pivotal role in determining the safety and structural integrity of your roof.
Roof decking is the foundation of your roofing system. It is the base layer that connects the roof to the home. The roof deck is placed between the structural components, such as the trusses and joists, and the insulation/weatherproofing layers. When it comes to your roof rotting, you want to take all the steps necessary to ensure the health of your
Roof Decking Materials
Roof deck materials come as 4 x 8 sheets in a variety of different material options. The most common type of roof deck material is plywood, which comes as either OSB (Oriented Strand Board) or CDX (C to D Exposed). Other roof decking materials include steel, concrete, and cement. The main determinant of the type of material you should use is based on the amount of weight that the roof deck will need to carry, plus the weight of air conditioning equipment, rain and snow. For most residential projects the common choice of roof deck materials are OSB or CDX plywood. For commercial projects, steel, concrete, and cement are more commonly found in the roof deck. These materials are definitely interchangeable depending on your project requirements, however for now let us focus on three main materials; OSB, CDX, and steel.
OSB Plywood
OSB (Oriented Strand Board) was originated in the late 1970s as an extended use of waferboards. It separates itself from other wood-scrap materials because the long strips of wood are placed strategically instead of randomly, hence the name “oriented” because the wood strips are oriented strategically to improve the strength qualities from the waferboard. OSB Plywood is made from heat-cured adhesives and rectangular-shaped wood strands that are arranged in cross-oriented layers. Because OSB uses small wood strands for production, it is considerably less expensive than standard plywood. When produced in large, continuous sheets, the OSB is a sold-panel of consistent quality with a few voids or gaps. OSB Plywood is more susceptible to absorbing moisture and swelling up than CDX, due to the release of compaction stress in OSB created during the pressing of wood chips into the panels. Swollen OSB will remain permanent, to a degree, causing leaks, increasing decay, and creating uplift of whatever materials lie above.
CDX Plywood
CDX (Class C to D Exposed) Plywood is the lowest class of plywood and is often used in the construction industry or as a base to create other materials. Plywood is made from thin layers of wood that are peeled from a spinning log, called veneers, that are cross-laminated and glued together with a hot press. Throughout the thickness of the sheet, the grain of each layer is laid perpendicular to the adjacent layer. The final product is an odd number of layers so that the balance is maintained around the center. Since CDX is made from whole layers of logs as opposed to small strands, the plywood is much more consistent and has a less rough appearance than OSB. CDX is lighter than OSB, retains nails and screws better than OSB, and produces less swelling when exposed to water and will return to its normal thickness after drying. This feature alone is enough for roofing contractors to prefer using CDX Plywood over OSB for their roof sheathing.
Steel
Steel or Metal Roof Decks have been around since the 1930s/40s. The Steel Deck Institute (SDI) has been the biggest force in setting the standard when it comes to the design, manufacture, quality control and construction practices applied to cold-formed steel decking. The steel deck is roll-formed from structural quality sheet steel and is made to span over the roof joists or purlins to provide a flat surface to apply the weatherproof roofing. The variations in its thickness, shape, and depth can be used to meet the variety of loading requirements and spans. The steel deck’s versatility also allows for it to be used in more unusual configurations that may be sloped or curved. Steel decks are usually more costly than materials like plywood however, they provide increased longevity, durability, and a better strength-to-weight ratio backed by years of proven satisfaction in the roofing industry. Steel decks are more commonly used for flat roofing systems, which are typically used for commercial roofing projects.
How Can I Tell When My Roof Is Rotting/Corroding?
As a homeowner, you want to do anything that you can to keep your home safe from the elements of mother nature. Your first line of defense is your roof, so how can you tell when your front line is starting to deteriorate?
First things first, is it even safe for you to check your roof? We do not recommend grabbing a ladder and going on your roof to do an inspection. According to the American Association of Orthopaedic Surgeons, last year there were about 500,000 ladder-related injuries due mainly to homeowners trying to clean out their gutters or perform their own roof inspections/repairs. Our team of certified roofing contractors have specific equipment and years of experience in doing roof inspections safely and thoroughly and will provide a free, no-obligation estimate for any repairs or replacements needed.
With that being said, there still are some telltale signs that you as the homeowner can check for yourself to see if an estimate would be needed.

Roof Rotting
Here is a list of signs that your roof deck may be damaged or rotting:
- Shingles curling, cracking, or buckling
- Missing shingles
- Holes in the roof
- Mold or mildew in the attic
- Spongy feel when walking on the roof
- Granular wear to shingles
- Damage around chimneys, pipes, and other penetrations to the structure.
- Wet spots on your ceiling
- Sudden increase in electric bill
There are some DIY inspections that you as a homeowner can do to find the beginning signs of roof deck damage.
- Attic Inspection: Carefully make your way up to your attic and check for any signs of rotting wood. Do you see any signs of staining or moisture on any of the plywood or insulation? Can you feel any dampness in the wood? Is there a musty mold smell lingering? Can you find any holes, possibly made by a new furry neighbor? Is your attic fan and ventilation system free of dust & debris and circulating the air properly?
- Ground Check: You can take a trip outside and stand in front of your home to view your roof from the outside. Are there signs of curling or missing shingles? Can you notice any sagging or structural integrity issues with your roof?
- Research Roof’s Age: Severe weather or a poor ventilation system can decrease the life expectancy of your roof. If your roof is more than 20 years old, it’s a good idea to reach out for a professional roof inspection.
Roof Deck Corrosion
Roof deck corrosion occurs when using steel for your roof deck construction and has been exposed to water either from a hole created from severe weather or poor roof or insulation installation causing gaps between the roofing and insulation and allowing for water exposure.
WARNING: We do not recommend walking on a damaged metal roof structure. Corroding metal roof decking can cause structural instability which can lead to the roof collapsing if too much weight is put on the structure, leading to injury. Please refrain from having work done on units on your roof if you suspect instability in your roofing structure.
Some visible signs include:
- Visible rusting in roof deck
- Pieces of roof deck missing or falling from structure
- Wet or damp insulation
- Holes/leaks in roof
If you believe that your metal roof decking may be damaged, immediately have a professional roofing contractor, e.g. Infinite Roofing, come do a thorough and safe inspection of the roof.
So What Do I Do? Repair or Replace?
Rotted or corroded roof decks, whether made of plywood, steel or any other material, cannot be repaired and must be replaced. Contact your local certified roofing contractors and set up an appointment to have the damaged roof deck to be replaced.
Our professional roofing contractors here at Infinite Roofing would replace the rotted roof decking, along with the top of the line GAF and Versico accessory products to help prevent further roof deck rotting or corroding such as:
- Lifetime Roofing Shingles
- Proper Attic Ventilation
- Proper Roof Deck Protection
- Ice & Water Barriers
- Starter Strip Shingles
- Ridge Cap Shingles
Adding these top of the line products will increase the longevity and durability of your roof decking. When it comes to protecting the welfare of your home and family, you want to have the best certified roofing contractors and products out there. Here at Infinite Roofing, that is exactly what we intend to provide for you.
Leave a Reply