At the edge of the roof, gutters capture the rain water and channel it to the downspouts and drainage lines below, conducting the water away from the house before it can damage vulnerable parts of the walls. The Wall System. Rain drops roll down the house's painted siding, are deflected by the sloping window sills, and bounce off the weatherboards. Not a single drop gets in to your cozy interior. Wall System Overlapping clapboards or wider weatherboards serve to shed rain, just like roof shingles.
Trim boards protect the edges of the relatively weak siding materials.
A thick, wide water table board may run along the lower edge. While its top, beveled edge sends water away from the wall, the lower edge sends it away from the foundation wall below. Moldings and lesser trim boards close any remaining gaps to the weather. Windows make the wall itself useful to people by keeping the weather out, providing light, and letting air inside. Moreover, they perform complex functions through their sliding and close-fitting connections.