Prior to the use of starter flashing, most roofs did not have a flashing installed. Without this flashing the sheathing along the eave edge would deteriorate over the years of exposure. Most of the time the sheathing would become so deteriorated that it would need to be replaced and usually before the roof needed replaced. A costly repair that could be avoided with the installation of a flashing.
What is a starter flashing? The term was coined from a roofer which describes the flashing that is installed under the starter course thus the name starter flashing. There are many different types of starter flashing but the type we are speaking of for the Seattle market has the dimensions of 1″x3″. A one inch hemmed leg and a three inch apron. What is the purpose of starter flashing? Well it does have two main purposes the first of which protects the sheathing edge from deterioration and the second function supports the underlayment and asphalt shingles from drooping into the gutter. A quality roof job should consist of this flashing to assure the roof structure will keep it’s integrity over the years.
The next time you re-roof be sure that the contractor you hire specifies and installs the starter flashing. The added cost is cheaper than making structure repairs later.