How to Protect your House from Damage Using Roof Flashing

flashingWater can seep into your house walls and cause damages to your building. If your house has mold and moisture problems, this might be occasioned by the water. To prevent these problems buildings are installed with roof flashing. Roof flashing is a material used over the joints in a roof to prevent water from leaking or seeping in. It is usually a form of aluminum, copper, sheet metal, plastic or galvanized metal. Galvanized metal and aluminum are the most popular and are said to be the best option. If you are going to install the roof flashing yourself, use aluminum as it bends easily.

Roof flashing is installed in intersections like edges around a vent, skylight, chimney, roof valley, or soil stacks. There are many pre-made roof flashing out there already shaped depending on where they are used. These pre-made roof-flashing include Vent pipe flashing, step flashing, valley flashing, and drip edge flashing. How the do you install roof flashing?

  1. Step flashing

Step flashing is shaped in a way that allows it to fit each course of shingle. Many choose step flashing because even if one piece fails, the water will hit the next one. The water is then directed to the shingles, and it drains down the roof. When installing step flashing for chimneys, lay the base about 4 inches past the ends of the chimney and bend it to go around the chimney and the base. Use plastic roofing cement under the base of the flashing and galvanize with roofing nails. Do this around the chimney without attaching the top piece bending around the chimney. Wrap the counter flashing around the chimney. Leave a one-inch gap between the bottom of the side flashing and the shingles. Seal the top of the counter flashing together with any holes with the plastic roofing cement.

  1. Valley flashing

roof flashingThese are “V” and “W” shaped flashings used in the valley areas of the roof. Lay a waterproof membrane before installing the valley flashing if you live in areas with lots of ice and snow especially. Set the flashing on top of the underlayment as per the manufactures direction. Ensure that it is aligned with the drip edges at the end. Trim the flashing and nail along the outside edges every foot or so. Seal the seams and nail heads with roofing cement.

  1. Drip edge

Install them after the valley flashing. They are attached along the edge of your roof using nails as they are corner shaped. Mail them over the fascia board but under the builder’s felt. Make sure that you cover the nail’s head with roofing cement. To protect a felt from rain and the wind at any overhang, install the drip edge over the felt and fascia.

  1. Vent pipe

To install a vent pipe flashing, slide the flashing over the vent pipe and tuck the uphill part of the flashing under the shingles. Fasten the flashing with galvanized roofing nails and apply roofing cement to the nail heads and bottom tabs of the shingles that were disturbed.

You can also opt to buy flashing in bulk and cut and bend it to go around different objects that might be on your roof. Provision for cuttings waste when purchasing the in bulk to shape on yourself. Also, note that you need to install the top edge of any flashing in a way that it doesn’t come into contact with the sheathing or wood panel.


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