Flashing is often your home’s last line of defense against water damage. There are several different materials that are commonly used for flashing and each is best suited for specific situations and in combination with different building and roofing materials. Before we talk about the different types of flashing materials, let’s take a minute to talk about what flashing is and how it works.
What is Flashing?
Flashing refers to the materials used in joints on the roof or walls of your home. Its job is to prevent water from seeping in and causing damage to the home’s walls and ceilings, causing structural damage to the home, or creating moisture and mold problems throughout the home.
On the roof flashing is found anywhere there is an elevation transitions in a roof line. This includes valleys, around chimneys and pipes, around dormers, and around any skylights or other structures that come up through the roof. Flashing is also commonly found beneath the first course of bricks on a home or chimney, above all wood trim around doors and windows, and where stairs and decks attach to the home.
How Flashing Works
Flashing works by directing water to flow around openings instead of over or into them. When installed correctly, flashing provides protection from its layers by the way it is installed. When used on the roof, flashing is placed under the shingles and around any protrusions like chimneys and pipes with a base that rises above the roof slightly. The shingles or roofing materials are then placed over the flashing. This will guide water around the protrusion and down the roof.
When used on valleys, joints, and other seams, flashing is placed across the joint and underneath the roofing material and usually bent in a way to provide a valley for water to flow down and away from the home. When flashing is used on external decks and stairs, it is placed in an “L” shape along the base of the structure where it meets the home, and against the side of the home. This prevents water from seeping behind the base of the structure where it can cause problems.
Common flashing materials
The type of flashing material used will depend on where it is being installed, how visible that location is, how much the budget is, and whether any aesthetic or historical appropriateness needs to be considered. The most common choices include:
1. Copper and Lead-Coated Copper
This is one of the most durable materials to use for flashing, but it is also the most expensive. Copper is a relatively soft metal, however, the technique to form it properly requires experience and practice. Joints can be soldered together easily to create watertight seals for custom applications. Copper will eventually age to show a green patina that gives an architectural authenticity to some styles of homes.
A common choice for chimney flashing, valley flashing, and base flashing, aluminum is versatile and durable especially when a finish is applied to extend its life. Aluminum is also more affordable than copper although aluminum without an applied finish cannot be used in direct contact with concrete, cement, and certain types of treated lumber as these materials will cause it to corrode. Joints in aluminum flashing must be overlapped or caulked with special sealants and usually require an experienced installer for larger jobs to ensure a water tight seal.
Lead is one of the oldest and most durable materials used for flashing. The health risks associated with lead have caused it to be replaced with safer materials, however, lead is still used in areas that are not easily accessed that also need long-lasting protection from water. Special handling is required for lead application.
4. Galvanized steel
One of the most affordable choices for flashing, galvanized steel is commonly used around chimneys and in valleys. Pre-formed pieces are usually available making installation easier. Galvanized steel can also be painted to allow easier blending with the structures and roofing of the home. It is, however, the least durable choice of metal and isn’t recommended for use in harsh conditions or with long lasting roofing materials such as tile and slate as the flashing will have to be replaced long before the roof.
5. Galvalume Steel
AJ Wells preferred flashing metal is galvalume steel. This material is most commonly used because of the combination of the barrier corrosion protection from the aluminum as well as the galvanic protection capabilities from the zinc.
6. Stainless Steel
A very durable material that is well suited for harsh environments, stainless steel is a better choice for some climates than galvanized steel although it is more expensive and requires special tools to configure properly. Stainless steel flashing is often prefabricated in the shop before bringing on site. Stainless steel is also not affected by contact with concrete or masonry and makes a suitable alternative to aluminum in those circumstances.
7. Roofing Roll
This is a soft material that comes in roll form and is quick to install. It is also very affordable and lasts about as long as a typical asphalt shingle installation making it a common pair. It is mainly used in valleys and requires no special skills to install. It is not as durable as other choices, however, and can shrink under certain conditions so it is generally used sparingly.
The Importance of Proper Installation
In order for flashing to protect your roof and your home from seepage and water damage, it must be installed properly. Improper installation can give the appearance of a protected home while devastating damage is occurring unseen underneath the flashing. Repairing deteriorated flashing can require taking up large sections of the roofing materials, and damage underneath can result in expensive additional repairs.
Confusing? AJ Wells Can Help
When the correct flashing materials are chosen for your climate, roofing or building materials, the flashing will protect your home. Proper installation of flashing will protect your roof, the structure of your home, and everything underneath it from the dangers of water damage. If you’re not sure which product or material is right for you, let our professional roofing contractors help you choose so you can feel confident that your home is protected. Many roofing companies don’t understand how to properly deal with underlayment or flashing problems, with the experience and expertise from the Jacksonville roofers at AJ Wells, you can rest assured that every component of your roof and flashing material is properly installed and guaranteed.