Is It Raining Inside Your Place? Checked Your Roof Lately?
If the sounds “drip, drip, drip” are a big part of your life right now and if there are bowls and buckets spread out all throughout your home positioned to capture cascading droplets of water from several parts of your ceiling then there is a very good possibility that an expensive roof repair or a replacement may be in your “not to distant” future. But just in case, you may want to read on and find out whether you have a less expensive alternative.
Many of us assume that a leaky roof means replacement is imminent, and often that’s true, but such may not be the case at your place. It could be a flashing problem. No, not the kind where naked people are involved. That’s a different kind of flashing. The kind of flashing we refer to is the kind that helps to make a roof water-tight. And it doesn’t make any difference what kind of roof you have either. Flashings are a part of every roof. Flashings keep water out at certain locations where the roofing itself can’t. For example: Most types of roofing aren’t capable of sealing themselves to pipes and ducts, or to skylights, or to intersecting roofs or intersecting walls. Flashings actually make water-tight connections possible at these locations. Actually, a flashing is nothing more than a shingle itself. Take a vent pipe that goes through the roof for example: A vent-pipe flashing is used to seal the penetration. Essentially the flashing is nothing more than a large, flat metal shingle that contains a piece of rubber (in its center). The rubber portion of the flashing seals itself tightly around the pipe and the large, flat metal portion easily laces into surrounding shingles. On a flat roof the same rubber grommet also is used to seal itself to the pipe while the large, flat portion provides ample surface area to facilitate a good connection to tar and other types of flat (and low slope) roofing materials.
Flashings are made from a variety of materials the most common of which include: galvanized sheetmetal, fiberglass or plastic, lead, and yes, even copper. Heavy-gauge galvanized sheetmetal is by far the most common flashing in use today. It is relatively inexpensive and easy to install, and if properly maintained, it can last a lifetime. Lead is used almost exclusively on certain tile roofs and although copper flashings can last longer than galvanized sheetmetal the cost is generally not worth the extra life.
By telling you a little bit about how roof flashings are connected we hope to give you an idea about 1) how they can leak, and 2) how they can be repaired or replaced.
In places where the roof intersects with a wall, the flashing is ‘L’ shaped and travels the entire length of the connection. It resides behind the wall covering (siding or stucco) and beneath the roof covering and therefore its existence may not be so obvious. The flashing travels up and behind the lower edge of the exterior wall covering at least six-inches preventing leaks under even the most torrential downpour. The roof side of the L-flashing is connected to the roof material with hot tar or some other sealant.
On pitched roofs wall to roof connections are slightly different. Where the roof and wall are parallel the flashing resides behind the wall covering and above the shingles. Where the roof slopes along a wall the flashings are still L-shaped, but not continuous. At pitched areas the flashings are shingle length and overlap in the same way that shingles do – one end lacing into the shingles and the other side fitting behind the exterior siding.
A slightly different technique is used to connect the flashing to masonry. The connection to the roofing is the same. However, with stone and brick the flashing is laced into a mortar joint and literally mortared in place. A second flashing is used to cover the point where the first flashing is mortared into the masonry. It also is tied into a mortar joint – six- or seven-inches further up the masonry wall. The upper flashing is known at the “counter-flashing”. We think it ought to be called the cover flashing. You pick! In any event, with two flashings together – both mortared in place –- water-tight connections can be made between the roof cover and a vertical masonry surface.
The point at which two pitched roofs join (at an inside corner) is known as a valley and is where most shingle materials rely a piece of metal for a water-tight connection to each other. Yes, you are correct sir! This one is known as “valley flashing”. With all of the shingle nailing that goes on along the valley flashing there is a very good possibility that a leak can result. This occurs occasionally in new roof installations.
Flashings also exist at the roof’s edge to protect damage to barges, fascias, rafter tails and other wood parts that can easily be damaged by watershed. Edge flashings travel under the roof covering and over the wood in question. Generally these flashings would not be a culprit in the case of a roof leak because the normally reside outside the leak area – at the outermost edges of the roof.
Off the roof many other connections depend of flashings for water-leak prevention. Horizontal joints between stacked sheets of plywood siding use something called ‘Z’ flashing to keep water out. The flashing starts on the face of the lower sheet bends over to cap the top of the lower sheet and then travels up behind the sheet above – sort of in the shape of a backwards Z. Other Z flashings are used at horizontal connections between exterior siding and penetrations such as doors and windows. A similar flashing used at cantilevered wood decks and at waterproof decks whether cantilevered or not. What you might have determined as a roof leak could actually be a leaking deck flashing letting water into a wall from one or more stories above. By the way, water can travel down as many walls as there are that exist. There is no limit.
As you can now see flashings of all types play a big roll in preventing water from getting into your home via the roof and walls. How’s that for a segue back to leaks? Because they are metal and/or rubber (and generally not regularly maintained) metal flashings corrode, rust and otherwise deteriorate to a point where they can leak – sometimes long before the roof or siding material is even close to failing. The rubber section of a pipe flashing usually fails long before the metal portion does.
Whether it be a roof or siding leak it is very important to check the flashings first. Regardless of where they are they are usually easier and less expensive to repair than alternative patching or replacement. When drip, drip, drip is the sound you’re listening to it’s time to check flashings. And don’t just look for a leak in a flashing. Sometimes the hole is hidden under roofing, counter flashing or mortar. Test flashings in the area of the leak. If rubber is near the leak test that part first.
By the way, keep in mind that flashings of all types last longer a fresh coat of paint is applied every several years. How simple could it be? And, that’s all there is to it.