From weather conditions like strong winds, torrential downpours, heavy snow loads and harsh ultraviolet (UV) rays to other elements, such as fallen tree branches and critters, there is a myriad of things that can cause premature damage to roofing shingles. But the thing is, the problems do not stop there. What is also susceptible to extreme damage is the material located underneath the shingles called decking. While a little bit of damage to this component might not seem too urgent of a matter to some homeowners, it can actually lead to a host of serious issues — not to mention hefty repair bills — if left unaddressed for too long.
What Is Roof Decking?
Roof decking, also called sheathing, refers to the layer of materials located above the rafters and below the underlayment, which is installed beneath the shingles. It is considered the foundation of the roofing system that connects the roof to the house. It has to be strong to bear the weight of the roofing components but flexible enough to give in slightly under load or during high-wind events.
An important function of roof decking is to help regulate the moisture levels inside the home. It keeps rain and snow out and allows excess moisture to escape through the attic.
What Is the Best Material to Use for Roof Decking?
In residential roofing applications, roof decking is commonly built using plywood or a plywood composite known as oriented strand board (OSB). OSB is made from wood strands, which are mixed with waterproof resin and interweaved together in thick mats. Similar in strength and performance to plywood, it resists warping and distortion. When it comes to protection against moisture, however, plywood remains the better choice despite being more expensive than OSB by a few dollars per panel.
How Can Roof Decking Get Damaged?
Roof decking can be damaged due to many different reasons. One instance is if snow sits on the roof for an extended period, which is why it is important to periodically check and clear the roof after at least six inches of snowfall. This is because ice dams can start forming at this depth. Flat roofs are also more prone to damage since they do not clear as fast as pitched roofs.
Damage to the decking can also occur in segments of the roof where shingles are missing as a result of advanced age or deterioration. Most roofs are designed to last for approximately two decades, though the actual service life largely depends on the quality of materials and installation, local climatic conditions, and roof maintenance practices.
Another thing that can lead to damaged decking is poor ventilation in the attic. Over time, a hot and humid attic can set off the warping of the decking. Albeit rare, the incorrect installation of solar panels on the roof can also cause decking damage. A home solar power system is a great way to dramatically reduce energy costs, but roof-mounted solar panels still pack weight. All that extra weight can cause the decking to split.
Finally, one of the worst things that roof decking can encounter is water damage. Since it is primarily made from wood or wood composites, roof decking is particularly susceptible to various forms of water damage. Once it has developed rot, then it has reached the point of no return.
What Causes Roof Decking to Rot?
Water can seep into a roofing system in many ways. Missing shingles, overflowing gutters, torn flashing around chimneys and vents, ice dams in the winter, and excessive humidity in the attic can all allow moisture to gradually make its way into the roofing system and contribute to the rotting of the decking. A leak is an obvious sign of unwanted water in the roof. If not patched up on time, it can lead to the growth of mold and mildew, damage to the structural supports of the roof and, in some cases, fire if it comes in contact with electrical wiring.
What Are the Signs of Rotted Roof Decking?
You need to watch out for a number of signs to spot damaged roof decking. One of them is a roof leak, which can lead to dark-colored stains or discoloration on the ceilings and interior walls, peeling wallpaper, or bubbling or cracked paint. A brief inspection of the attic can help unearth streaks on the rafters or in the insulation. Light beams passing through the room also signify the presence of gaps or holes in the roofing installation.
A sagging roofline is another clear indication that there is a serious problem with the structure of the roof, including the decking. When waterlogged, the decking can begin to warp, and in almost all instances, this can lead to a deformed ceiling and roofline.
Should Damaged Roof Decking Be Repaired or Replaced?
When the roof decking has sustained water damage, particularly rot, a simple repair job is simply not an option. It must be fully replaced instead. If the replacement of damaged decking is put off, it can open the floodgates to a host of problems and repairs. Sure replacing a roofing system is a costly and time-consuming process, but it is certainly less expensive in the long run than having to replace affected parts of the home, such as stained drywall, water-damaged electrical connections, and waterlogged roof joists and beams.
When it is time to replace your damaged roof, make sure you find a roofing installation company that specializes in the type of roofing structure you have. Reputable roofing contractors use high-performance underlayment to support the shingles and protect the roof decking. Roofing underlayment also adds an extra layer of protection to vulnerable areas in the roof, like the seams and edges where water is most likely to penetrate. A good roofing system also includes ice and water barriers. It also comes with a strong warranty, increasing the level of your comfort and peace of mind.
Why Are Roof Inspections so Important?
The roof is exposed to weather conditions all year round. That is why the National Roofing Contractors Association (NRCA) recommends that you should have it inspected professionally at least twice a year — once in the fall after the hot and humid weather has subsided, and once in the spring after the onslaught of snow and ice has faded out of the picture. It is also a smart move to perform an inspection after a big storm, hurricane or other hazardous weather event.
Routine inspections are crucial in understanding the condition of the roof and managing its needed maintenance. For example, an experienced roofer can identify improperly installed flashing membranes around dormers and suggest an action plan to remedy that problem — which is to use step flashing, a structural metallic barrier specially used between the walls of the dormer and the roof, to help prevent leaks in that area. With regular inspections, you will learn that small repairs are necessary to ensure your roof can effectively resist the effects of year-round weather conditions.
Roof inspections can also help you determine whether you need to file a claim with your insurance provider. When a claim is filed, your insurer and roofing company will work together to perform the repairs or replacements needed to restore the condition of your roof.
