Protecting Your Property from Wood Rot
You can’t see them, but they can make a beautiful property look dilapidated. They are not visible to the naked eye, but they can threaten the structural integrity of a large building. When they attack, they can turn solid wood into pulp. What are these evil creatures? I am speaking of fungi, of the wood decaying variety. These organisms need only water and warmth to begin their campaign of destruction. Once warmth and water are introduced to wood, the fungus spores will blossom and begin to grow and feed, and ultimately destroy the wood where they reside. Many times this damage is undetectable until it is too late. Before you know it, your property is covered with wood rot, residents are unhappy, and the property looks terrible. Fortunately there are some ways you can prevent wood rot from occurring, but you have to know what to look for and stay vigilant.
The Building Envelope
Buildings are designed and constructed with water infiltration in mind. The area of architectural and engineering practice related to this issue is called Building Envelope Design. The Building Envelope includes all the building components that separate the interior environment from the exterior environment. It serves as the outer shell of the building and includes the exterior walls, foundations, roof, windows, and doors. Building designers take into consideration 4 major performance objectives when designing the building envelope:
1. Structural Integrity
2. Moisture Control
3. Temperature Control
4. Control of Air Pressure
Moisture Control is the most important of these objectives relative to wood rot. The building envelope is designed to control the rain and direct it away from the structure to prevent high moisture content. If moisture content is above 20%, it provides a potential breeding ground for fungi. Below are listed the primary areas of where water infiltrates the building envelope and causes wood rot. When performing your periodic inspections, be sure to look for failures in any of these areas. If you identify a failure in the building envelope, it is important to address it immediately to mitigate the amount of damage.
Causes of Wood Rot
1. Failing Caulk
Caulking refers to the use of a flexible sealing compound to close gaps in buildings other structures against water, air, dust or insects. It is an essential component of the building envelope and plays a pivotal role in protecting your property against wood rot. It is important that you inspect the caulk joints regularly, because once the caulk fails, your wood will begin to rot soon thereafter. Typical places where you should inspect are the Trim/Window Joint, the Trim/J-channel Joint, or the Window/Brick Joint.
2. Failing House Wrap
House wrap is the water resistant barrier, usually installed beneath siding that prevents water from entering the wall assembly while allowing water vapor to pass to the exterior. The brand most commonly known is Tyvek, however there are other options available. Common failures of the house wrap are due to missing house wrap, breaks in the house wrap or reverse lapping of the house wrap. House wrap should be installed beginning at the bottom and working your way up the building so that the top layers overlap the bottom layers. There should be no breaks and seams should be taped.
3. Missing Cap Flashing
Cap flashing is a form of flashing which is designed to protect against water infiltration over windows and doors and other similar penetrations in the building envelope. It is typically a metal such as aluminum or copper and is impervious to water. Cap flashing is an effective waterproofing element in the building envelope but is not always installed. If you find that an area of window/door trim is continually rotting, you should consider installing cap flashing. If rot is occurring where cap flashing is installed, then the cap flashing is most likely installed incorrectly.
4. Faulty Siding
The purpose of siding is to shed water away from the building. It is important then to look for any areas in the siding that might trap or collect water instead of directing it away from the building. The J-channel is a common problem area, because it is installed around windows and doors and siding terminations. If the horizontal pieces are installed incorrectly then the J-channel will collect water which can then enter the building structure. It is also important to inspect all penetrations through the siding such as hose bibs, HVAC disconnect lines, dryer vents, light fixtures, etc. Make sure these areas have proper flashing or are sealed properly.
5. Roof Leaks
Roof leaks are a very common cause of wood rot. What makes roof leaks tricky is the fact that water often travels great distances along the rafters before entering the wall. This means that the wood damage could be 50 feet away from the source of the leak. It is important to have regular roof inspections from a qualified roofer, or to promptly make roof repairs when discovered. Roof inspectors should check for missing shingles or flashing, ensure that all roof penetrations are sealed, and make a determination on the remaining life of the roof. If possible, they should enter the attic to check for water stains on the roof deck or rafters.
6. Gutter Leaks
It is very important to make sure your gutters are functioning properly. If they are not functioning properly, water can pour out in large quantities onto various parts of the building envelope that are not intended to handle that much water. Keeping your gutters clean is the best and easiest way to avoid this from happening. You should set up a regular cleaning at least twice a year. Over time gutters can begin to sag, so you should check to make sure the gutter is sloping downward toward the downspout. Also inspect all joints and terminations to make sure they are properly sealed. You should also have a qualified gutter installer determine if your gutters are large enough to handle the water runoff of a roof your size.
Many property managers are using this information in defending their property against wood rot and have reaped the benefits. You are now better equipped to win the battle against the nefarious wood decaying fungi. The more diligent you are in staying on top of the above mentioned areas, the more money you will save in the long run and the better your properties will look.