Window Sills

Important details for window sills are:

• - minimize the number of joints
• - ensure minimum slope of 15° to sill
• - provide drip groove
• - provide adequate flashing including end dams
• - caulk all joints

The most fail-safe detail is to choose a stone, concrete or metal sill material that is tailored to the window opening and has a slope on top and a drip groove/lip on the under side.