Most problems in building structures are caused by stagnant water and leaks. Keeping water out of the roof is very crucial for roofing systems. If you want to maintain a dry & long-lasting roof, it is essential to familiarize yourself with the term “roof flashing.”
The primary purpose of this article is to provide information about the different types of roof flashing available in the market. By knowing these types, you can easily engage in a discussion with your roofing contractor regarding the specific type of flashing you require for your roof.
What is roof flashing?
Roof flashing refers to a thin sheet of metals used to prevent water penetration into the roof and to direct water away from certain areas of the roof.
It is primarily used where there is an intersection whether it is between a roof and a wall (or) between roofs. It is an essential part of the roof. If it is not fixed properly, then it can lead to a roof leak which may be costly to fix.
Types of roof flashing
There are various types of roof flashings available and it has been used in various places on the roof. Some of the major types are listed below.
1) Step flashing
Step flashing is a widely used type of roof flashing that plays an important role in preventing water infiltration at the intersections between the roofing material and vertical structures like walls or chimneys.
To block water from infiltrating the roof, a piece of metal step flashing is positioned underneath a shingle or any other roofing material, with the other end fitted against the wall. This arrangement ensures that water is directed away from the roof.
During installation, individual pieces of step flashing are layered on top of each other, creating a barrier that allows water to flow down the roof without seeping into the underlying structure.
2) Continuos flashing
It is a long continuous piece of metal sheet that channels water from the wall to the shingles below.
It is used at the base of a dormer or chimney walls to prevent water from getting into your roof. It is also known as “Apron flashing”.
3) Counter flashing
Counter flashing is commonly used at places where the roof meets the vertical wall, for example, a chimney. There are two layers in the counter flashing.
The first one is the base flashing and is provided at the bottom and the second one is fixed at the top of the base flashing and the other end is inserted into the wall by cutting a groove into the wall.
The main purpose of counter flashing is to divert the water that drips off from the wall to the roof to prevent water leakage at the wall–roof joints.
4) Drip edge flashing
It is used to protect the roof edges from water intrusion. It is installed along the eaves and rakes of the roof.
The primary purpose of the drip edge flashing is to divert the water away from the fascia to prevent the water from seeping into the underlying roofing structure. It channels water from the fascia to the gutters.
It covers the gap between the roof deck and fascia board called “Carpenter’s gap” thereby restricting the entry of unwanted pests into your home.
5) Valley flashing
The flashing provided in the area where two roofs met together to form a valley is called valley flashing.
The primary purpose of valley flashing is to direct water away from the valley by channeling down the water thereby preventing the water pooling and seepage into the roof structure. It is installed along the valley.
The shape of valley flashing can be either a V or W shape. The valley flashing can be made of aluminum, stainless steel, copper, etc. Since it is visible from the top, it can dramatically increase the appeal of the roof.
6) Vent pipe flashing
Vent pipe flashing is specifically designed to protect the areas around the vent pipes, which extrude through the roof.
It is used to create a water-tight barrier around the vent pipe, preventing water from entering the roof through the opening. It is also used to cover up the opening between the roof and the vent pipe thereby preventing pests and debris.
7) Skylight flashing
Skylights are nothing but a type of window that is fixed on the roof. Skylight flashing is specifically designed to protect the areas around the skylight frame from water infiltration and debris accumulation.
Proper care must be given during the installation of skylight flashing as it involves integration with the roofing material.
8) Kickout flashing
It is a particular kind of flashing that diverts water from the roof to the gutter thereby preventing the water to reach the intersection of a wall, where it can be trapped.
The kick-out flashing is installed at the edge of the roof slope where it meets the wall. It is typically a metal piece, such as aluminum or galvanized steel, that is shaped like a mini gutter.
Materials used for roof flashing
The three commonly used roof flashing materials are,
1) Galvanized steel
These galvanized steel materials are coated with zinc to enhance its corrosion resistance. It can last for about 40 years or even more. It is slightly difficult to install.
It is the most commonly used material for roof flashing. It is easy to form any shape we needed and is also pretty much lightweight. It is the least expensive one among all the three and can last for 20 years or more. It is a thin material that can be easily broken if mishandled. It can easily get rusted, if proper care is not taken.
It is the most expensive one of the three. It enhances the overall curb appeal of the roof. It is light, easy to install, and even lasts for decades.
Common issues with roof flashings
1) Corrosion – The use of flashing materials in the roof will provide a long life to the roof by keeping the roof dry and out of the water but we should remember that these materials also have a limited lifespan so they will need a replacement at some point.
If they are not painted during installation, then they might need replacement or repair sooner because of corrosion.
2) Improper repair or installation – The time between the maintenance or repair is also dependent upon the workmanship of the roofing workers. For example, in flashing work, it is important to avoid any exposed fasteners.
All the fasteners must be concealed under the roofing material, but some contracts didn’t conceal the fasteners and over time it may get rusted.
3) Leakage of water – Improper installation or any damage to the roof flashing can create gaps and allows water to infiltrate. This in turn causes leaky roofs and many problems.
4) Separation of flashing material from the roof – Flashing that is not fixed properly at its place may get displaced due to high winds or snow loads etc.
5) Breakage of flashing material – Flashing materials can develop cracks and may even break in the long run due to constant changes in climatic conditions.
6) Lack of maintenance – It is essential to inspect the roof and roof flashings periodically so that the damages can be assessed and repaired early to prevent further damage. If this step is neglected, even small damage can cause a complex of problems in the long run.
1) What are the types of roof flashing?
- Step flashing
- Continuous flashing
- Counter flashing
- Drip edge flashing
- Valley flashing
- Vent pipe flashing
- Skylight flashing
- Kickout flashing
2) What are the types of roof flashing materials?
- Galvanized steel
Hope this article gives you some valuable information about Roof flashing. If you find this article helpful, let us know in the comment section.
Image credits: Lyonsroofing.com, JLConline.com, Deerparkroofing.com, Evobuild.com.au, Oatey.com, Skyspec.com, Stormmastersgutters.com