Roof Flashing

What are Roof Flashing Materials and What are They Used For?

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Roof flashing materials refer to thin layers of waterproof metal sheets used to cover and protect joints and angles especially where a roof comes into contact with a wall, edge, valley or chimney, to prevent leakages. The materials are installed in an overlapping pattern in such a way that they prevent water entrapment.


Most modern home builders usually use the following materials for roof flashing, however, the choice of the material depends on the following factors; Durability of the material, cost of the material, visibility by the observer, chemical compatibility with other materials they come in contact with and is the material historically appropriate for roof flashing.

  • Copper and lead coated copper – this is the most expensive material compared to other materials but extremely durable. It’s also compatible with most wood preservatives. Coating copper with lead enhances decline of its quality. Copper also requires no painting and other treatments.Copper is the most preferred for most flashing applications.
  • Aluminum – its durable and easy to form and relatively cheap. Aluminum is the best for a chimney, Valley or base flashing but a finish must be applied to prevent corrosion especially when it comes into direct contact with treated wood, concrete or cement. Aluminum flashing requires an experienced installer as it needs to be overlapped in order to ensure water tight seal.
  • Zinc – it’s rarely used in modern home building but extremely durable and requires less maintenance. Due to the oxidizing nature of zinc to form a protective coating its extremely resistant to weathering.
  • Lead – its soft, easy to bend and one of the oldest material used for flashing however it has several health risks but can be used in areas that need a long-lasting protection from water. Lead materials are also durable and mostly preferred for chimney flashing.
  • Roof rolls – its a soft material and easy to install and therefore does not require special skills.Its mostly applied in valley flashing however its not durable and easily shrinks under some conditions and therefore rarely used.
  • Teme-plate – the material is composed of a base metal of steel or iron coated with a mixture of lead and tin. Traditionally, the material requires frequent painting to prevent corrosion.
  • Galvanized steel – it’s cheap to purchase but not durable. It’s used most around the chimneys and in valleys. Galvanized steel can be painted to meld with other structures and roofing of your home. However, it’s not recommended in areas that experience harsh weather conditions or homes with lasting roof materials such-such as tiles as the flashing will have to be replaced long before the roof.
  • Polyvinyl Chloride {PVC} – the material is easy to work with and has an inert characteristic and it’s also not affected by treated wood.Mostly used in deck building.
  • Rubber based roof flashing materials for e.g. butyl,rubber and acrylic.They are less vulnerable to damage through thermal expansion

The above materials come in rolls of different lengths and widths but can be cut and bent right at the job place to fit your need.

Recently a new flashing material has been developed and has been proven to be the most effective. The material is referred to as Bituminous which has a sticky characteristic like Tar and is used along roof eaves to prevent leakages from ice dams. The material is distributed by different companies under different brand names, but the most preferred are vycor made by Grace Production Company. However, when used the builder should remember to protect it from direct sunlight and other materials for example aluminum.


Most home builders tend to forget about roof flashing however it’s usually a critical piece of the roof system that plays the following roles:

  • Keeps you dry – Adequate reinforcement of residential areas likely to leak, flashing can play a substantial role in protecting your home and properties within it from water damages. Its, therefore, a worth investment particularly for homeowners who live in areas with moist climates.
  • Flashing helps to make the roof system more durable and prevents against ice and moisture and makes leaks not likely to occur
  • Flashing assists to protect your house at the joints of your roof so that moisture, water, debris, and dirt can’t seep into cracks and consequently damage the substructure of your roof.
  • Flashing also protects potential weak points of slope or flat roofs from been damaged which can make the roof assailable to flooding.
  • Flashing prevents insects from penetrating into the roof and consequently causing damage of the structure.
  • It offers an aesthetic quality to the roof making it look slick, neat and well-polished.

Article provided courtesy of the Staten Island Roofing Company.

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