Flashing repairs and how they should be done.
Flashing is a vital component to any roof. It is also a common source of roof leaks. Flashing is normally a sheet of aluminum that seals your shingles or chosen roofing material to its surrounding walls and penetrations. Different forms of flashing can and should be used at different areas of your home depending on slope of the roof, material being flashed to, and the amount of exposure in a certain area. I hope to give some basic insight into flashing methods and general applications below.
Step flashing can be seen in the caption above at the ends of the copper roof where it meets the brick. The flashing is installed overlapping to ensure the water runs down the roofing surface. This method is not recommended for extremely low pitched roofs. Step flashing is the most common form of flashing around chimneys and wall penetrations and is very reliable. This form of flashing can last 50 years in some cases. This flashing is sealed to its penetrating surface with a sealant and in situations where the penetrating wall is masonry or stone, it will often be cut to allow the top side of the flashing to be tucked into the cut.
Valley flashing is essentially a sheet of metal placed in the valley sections of a roof. This is a normal practice on extremely steep roofs and is often exposed as the shingles are often not pliable enough to make the transition across the valley on extreme pitches. Valley flashing has changed some in recent years on lower pitched roofs. With the advent of newer products, such as stick down water proof membrane, it has become more cost effective for homeowners with all pitched roofs to have the protection of valley flashing. Sands Roofing has started using valley flashing in ALL valleys. Valley flashing can help protect one of the most vulnerable sections of your roof.
Counter flashing is normally used on porous surfaces such as brick and stone in place of step flashing. When a roof has counter flashing it will actually have 2 types of flashing used together to create a seal. The bottom flashing can be installed like counter flashing and the upper piece will be cut into the surface with a reglet to seal the upper flashing to the wall. It will then be installed to overhang the lower flashing creating a seal against rain. Some would argue that counter flashing is subject to water splashing behind the upper flashing while running down a steep slope.
All flashing will need maintenance over time. Sealant needs to be checked regularly. If the flashing is exposed to direct, hot sun in the afternoon, it will need to be checked more often. Sealant exposed to hot afternoon sun tends to dry out faster and crack, thus allowing leakage to occur. This does not mean it was installed improperly. The architecture of your home, as well as the amount of direct afternoon sunlight plays a large part in the longevity of flashing and the sealants lifetime.
Have your roofer talk to you about the different methods of flashing they use. You will find that roofers will vary on the method they choose to use and that is okay. The number one concern is to ensure that the roof flashing is installed correctly and a high grade sealant is used (not silicone caulk). Roof flashing will need maintenance as the sealant dries and cracks. If Sands Roofing can help give us a call at 803-520-6154