Advantages And Disadvantages Of 2 Common Flashing Materials

Roof flashing is used to prevent leaks around such structural roofing elements as vents and chimneys. Because of the wide variety of flashing materials available today, choosing between them often proves a daunting task for homeowners. This article will present the advantages and disadvantages of two common flashing materials:

1. Copper flashing

The primary advantage of copper as a flashing material is its high degree of durability. Because it is relatively pliable, it can be made to fit even complicated configurations with a minimum of joints. Where joining is necessary, copper can be easily soldered. Soldering, as opposed to mechanical or chemical fastening, is the strongest and longest lasting way to join pieces of flashing into a single, watertight unit.   

The main disadvantage of copper flashing is its high price tag. In addition, working with copper flashing requires a more complicated skill set, meaning it must be installed by experienced, accomplished craftspeople. This, in turn, increases the overall cost of copper flashing. In some cases, rain water running over the copper can also cause staining of other roofing materials. To avoid this, it may be necessary to install features such as drip edges and overhangs.  

2. Aluminum flashing.

Much cheaper than copper, aluminum falls into the middle-range where price is concerned. Overall labor costs are often lower due to the fact that aluminum flashing can be purchased preformed for a number of applications. Aluminum flashing may be installed unfinished, but it can also be painted. Painting not only allows greater aesthetic integration, but it also increases the lifespan of the metal, by protecting it from corrosive elements. 

Aluminum is highly susceptible to corrosion when exposed to materials with a high alkaline content. Unfortunately, the mortar, cement, and/or concrete used in chimney masonry and other rooftop brickwork are highly alkaline substances. Aluminum is therefore a poor choice for use in such situations.

Furthermore, aluminum cannot be soldered the same way that copper can. This means that pieces of flashing must be joined through a combination of mechanical fasteners and adhesive substances, such as caulk. The strength of such bonds relies heavily on the quality of the adhesives used--a fact which often drives the price up past initial expectations. And even when applied correctly, such fastening methods will not remain water-tight as long as soldered bonds.

Bottom Line

Choosing the right flashing material can be a difficult task. A number of factors must be carefully weight, including price, lifespan, and proper integration with other roofing materials. This information in this article should provide a good introduction to qualities of two of the most common flashing materials.   For more help, try contacting professional roofing companies.