No. 25
2007-02-22
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PROPER INSTALLATION OF DRIP AND RAKE EDGES

When replacing shingles on a roof, it is important to give proper consideration to flashing details on the drip and rake edges. Although drip edges are not currently required by the National Building Code, they are good roofing practice.

When water runs down the roof, it pauses a moment before pouring off. When this occurs, the water may run back under the edge of the shingles often wetting the roof deck. This could cause the sheathing or fascias to rot after a few years. The easiest way to prevent this from happening is to install a drip edge at the eave and the rake.

Preformed drip edge flashing can be made of aluminium, galvanized steel or copper. Though there are many shapes of drip edge flashing available, it is important to use a product which does not hinder water from running off the roof.

At the eaves, the drip edge should be installed before the eave protection membrane. At the rake, the flashing is installed over the underlay.

The above figure shows the correct application of the drip edge. The flashing should be nailed centered in the top surface every 8 to 10 inches.

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