Donald Hester
Washington State Licensed Home Inspector #647
WSDA#80050
InterNachi Member #NACHI10022401
509-670-9572
Contact Us
Washington State Licensed Home Inspector #647
WSDA#80050
InterNachi Member #NACHI10022401
509-670-9572
Contact Us
Blogs
The drop on the drip- Improper drip edge flashing
Submitted by DonHester on Tue, 09/25/2012 - 11:32. The drop on the drip- Improper drip edge flashings. Wenatchee and Chelan Home and Real Estate Inspections
Sometime even basic ideas are hard to do right. A basic principle of pitched roofing is the covering is a water shedding device. That means the control of water has to be from upper layer over the lower layer to create a shed plane. This is the basics of all roofing materials and their flashings.
In older home construction we used wood trim or moldings which would protect the edge of the roof decking from getting wet. These older roof decking materials consisted of solid wood planking, and even if it did get wet, in most cases the wood was able to dry without damage.
In modern construction we are using plywood or composite wood (OSB) for the roof decking. These materials especially OSB (oriented strand board) requires thorough protection from the weather. If not, they tend to suck up water like a sponge and will delaminate and rot away.
Add to this the ever present use of composite materials for fascias moisture protection is even more important. Without a drip edge, water may run down the side of the fascia and siding, causing staining and eventual damage.
The installation of drip edge is to prevent this water intrusion of these materials and to get the water to drip away from the materials below. So why is drip edge flashing seem to be so hard to install correctly?
(Note- the eave is installed over the rake)
The drip edge needs to be installed in a manner consistent with the shedding principle. That is that the upper layer is over the top of the lower layer.
The drip edge may also support the part of the shingle that extends past the decking along the eave. The drip edge should be under the builder's felt or ice guard and over the fascia.
As an extra precaution, you may want to cover the nail-heads with roofing cement then stick the felt down. At the rake (side), the drip edge is installed over the felt and fascia. (Note: High wind installations are different for the drip edges. The drip edge at the eave is installed over the underlayment with roof cement over the drip edge.)
Here is a short video on drip edge installation
If building practices were adhered to, we would create more durable buildings that will cost the consumer less money over the life of the structure. Too many times we take short term cost savings at the expense of long term replacement and maintenance cost.
“All things are cheap to the saving, dear to the wasteful”
Benjamin Franklin
NCW Home Inspections, LLC is a Licensed Washington State Home Inspection service located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Oroville, Cle Elum, East Wenatchee, Quincy and many more…
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