Now imagine that much water running down the face of your foundation, or splashing up onto the house at driveways, decks and steps, and it’s easier to see why water intrusion is an issue at basements and doorways and why wood rot occurs more often at lower locations on the exterior. Poorly managed runoff water can also cause erosion beneath the building’s foundation, driveways, walkways, patios and garage floors. Properly installed and maintained rain gutters, with downspout extensions that get the water away from your house, really are necessary for the long-term health of the building. And they do help in the winter too – splash-up from snow melting on the roof can keep surfaces near the ground constantly wet, especially over hard surfaces like decks, steps and driveways.