Leaking Roof Valley: How to Repair a Lead Valley

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  • 4-8 hours
  • Beginner
  • 25-70
What You'll Need
Replacement shingles
Roofing nails

If you have a roof valley in your home, then you may find that your lead valley starts to leak, or even to allow water to run onto the ceiling of the floor below. If you find that this is a problem, then you will need to repair your roof valley before anything serious happens, such as plaster loss, or even major water damage. A lead valley is a particularly difficult item to dispose of, as lead is toxic, and so a repair may involve simply patching up your lead roofing. Following some basic rules will give you a quick and simple way to repair your lead valley roof.

Step 1 - Find the Cause

Find the place where that leak is coming from. Many roof valley leaks are caused by roofing nails that have been poorly placed and are acting as a dripper, feeding water through from the roof above. The roofing nails are fine so long as the lead of the roof valley is intact, but once it starts to crack or fracture due to water pressure, corrosion or other damage, the nail provides a space for water to run into the home. Check the entire roof valley carefully to locate the source of these problems.

Step 2 - Remove the Shingles

Once the roof Valley has begun to leak, you will need to cover the valley with flashing in order to prevent a repeat of the problem. In order to lay the flashing, the shingles on the roof will have to be removed. You may want to carefully measure the flashing and only lift up as many shingles as you need to get that into the roof, or you may want to lift up a number near to the valley, in order to ensure that the roof is fully protected in the future. Place the shingles to one side for use later.

Step 3 - Lay the Flashing

Take your flashing, and lay it down carefully over the connection between the roofs. You may need to cut the flashing to fit, and you will also need to screw it in tightly in at the top and bottom, or seal using a waterproof adhesive such as caulk. Leave the flashing to dry completely before returning.

Step 4 - Replace the Shingles

Once the flashing is dry, take another layer of caulk, and spread it over the surface of the flashing. Start replacing your shingles. You may find that some of the shingles are damaged, in which case you should throw these away, and replace them with a different set. You may also want to use new roofing nails, taking care not to damage the flashing as you push the nails through the shingle. Cover the roof with a layer of roofing tar to protect the new flashing, and leave to dry.