Water Intrusion : Protect Your Home from Water Seeping in from Outside

Exterior Flood Damage

water intrusion San Diego CAAn important aspect of durability of a home is effective management of water like water intrusion. Having and attractive exterior finishing makes a home look good, but you cannot rely on those to give flawless protection from flood damage. None of the exterior finishes, be it stucco, siding or brick is water proof. Stucco and brick are porous while siding contracts and expands creating the gaps between boards. Water from snow and rain will penetrate all kinds of exterior finishes. That is why there is a need for a drainage plane in every home.

A drainage plane is layer of water resistant material which completely covers the exterior of home. It integrates with the flashing in order to give drainage a path from roof to ground. When the water penetrates the exterior finish, the drainage plan works with the interconnected flashing to guide the water back to exterior. Framing and sheathing is protected by the drainage plane from getting wet and the drainage plane also prevents the buildup of moisture in the exterior wall cavity. Here is how you can secure different parts of home’s exterior from water:

Water Intrusion Through Wall Cavities:

The housewrap has a design specially made to keep the water out of the wall cavities. In case some small quantity of water does get through, it is allowed by the housewrap to dry to exterior. The important thing in having effective installation of housewrap is to provide continuous coverage through lapping every piece shingle-style; the individual pieces should be lapped from the bottom to the top. Windows, the utility penetrations and the intersecting roofs are few of critical areas of houses which need special attention.


The openings of windows are quite vulnerable areas as they interrupt continuity of drainage plane. In order to help with prevention of water intrusion, the window opening should be sealed and flashed properly. It is important to correctly layer the pieces of flashing, in order to prevent the water intrusion from seeping behind the window flashing. The window flashing is layered in shingle style so that the water can be guided downwards.

Utility Penetrations:

When a dryer vent, hose bib or any other fixture is installed in exterior, a hole is created in the drainage plane. It is important for the drainage plane to be continuous so that water intrusion can be prevented. The continuity of drainage plane is maintained by flashing as it integrates with drainage plane and it directs the water away from the penetrations. Installing the preformed flashing panels is an effective of flashing penetrations.

Despite the best efforts, some of the water may still penetrate through exterior finish. When this happens, there is a need for second line of defense against intrusion of water so that the water is drained back to exterior. By installing the housewrap properly and by integrating it properly with flashing, the water is guided downwards and away from home, protecting the walls from water intrusion and flood damage.