Water Leaking Behind Siding

Rainwater leaking from a gutter ends up behind siding and causes a wall to rot.

Water leaking behind siding.

Vinyl siding is designed as an exterior cladding only and is supposed to be installed over other materials such as a weather resistant barrier. My photo above of ice below some courses of vinyl siding traces a moisture problem traced to improper installation of a through wall vent for a direct vent heating appliance. Some areas were extremely heavy. When the siding becomes damaged there s a higher risk of the water running into your walls which could lead to mold growth structural damage and a compromised foundation.

If there are gaps and water can get in you can use tri polymer caulking to fill it in. Preparation for siding while correct installation reduces the risk of water running behind the siding it can t completely stop it. Water leaks at soffit or eave overhang penetrations for chimneys that permits water to leak at the roof surface then pass behind the siding if the chimney is not properly flashed. Some areas were extremely heavy while others were just a single streak.

Vinyl is a potentially leaky material and water trapped behind siding leads to decay and mold. If an installer uses a material such as incorrectly this only exacerbates the problem. At some point in the past an owner had vinyl siding installed over old siding. While gaps and openings permit leaks behind the siding some siding openings are normal such as aluminum or vinyl siding bottom edge vents.

Bottom to top rain will hit the roof and make its way down your siding until it hits the ground. Step 2 you can also check above the window or door to see how the siding is attached there. As gravity takes over and pushes the rainfall downwards you better hope your siding was installed correctly. If your gutters are not directing the water to the downspout system the siding takes the brunt of the torrent resulting in wear and tear as well as water damage.

If it was installed properly there shouldn t be any water running behind the siding and causing issues. Check to be sure weep holes are open along bottom of window openings. Caulk along the seams of the siding where it meets the window. The extra thickness of the vinyl.

In this video this old house general contractor tom silva shows how to prevent water from leaking in behind vinyl siding. During a very heavy 2 days of rain water began running from between pieces of siding. This is a caulking that s flexible and works well with vinyl siding. However it is possible for water to get behind the siding if it s not installed properly.