Water Damage To Roofs

A leaky roof may be caused by a number of factors, including ice dams, poor roof design and/or accumulation of heavy snow in specific areas. Any of these issues may cause water to move under the flashing and leak into the home. Special care should be taken to ensure snow does not accumulate near flashed areas and roof eaves.

Ice Damming on the Roof

Ice dams can happen anywhere that cold weather results in freezing weather conditions. An ice dam is formed when the snow on a roof melts and runs down the roof toward the edge of the roof (the eaves). Melting can be caused by heat in the attic or heat from the sun, and is more common on south or westward facing roofs that receive more sunlight. Melted snow tends to re-freeze on the eaves of the roof where the temperatures are generally colder. As the area of ice grows on the roofʼs edge, it acts as a dam and stops water from properly flowing into the eavestroughs. As this blockage continues, water will begin to back-up under the shingles. If left unattended and allowed to buildup, ice dams can cause water to enter into the attic and possibly damage the interior of the home.

Did you Know?

Attics require circulation to properly expel moisture, heat and to prevent condensation problems. If you are considering adding insulation to the attic, make sure that you do not block air circulation to the soffits.

Preventative Measures

Where ice dams occur, removing ice formations and clearing away snow can provide temporary relief. Clear as much snow off the roof as possible, especially snow by the eaves, attic roof vents, bathroom vents and kitchen vents. Remove ice formations from the eaves and at the end of the valley that is formed where two roofs join – exercise extreme care, use safe work practices and do not damage the roof or roofing materials (i.e., shingles).

Warning Signs: Chronic Ice Dams

Chronic ice damming may indicate that the insulation in the attic has moved away from the area near the wall. Where ice dams are a re-occurring issue, check your homeʼs attic insulation and, if displaced, returned to its proper position. The Insulation should be positioned up to the exterior perimeter of the wall but should not interfere with the soffits and the exchange of air in the attic (See Chapter 3, Carpentry & Framing, “Attic Ventilation”). A cardboard batten is usually installed to maintain the necessary 2-inch space between the top of the insulation and the underside of the roof sheathing.

For more information on Attic Ventilation see Chapter 3, Carpentry & Framing, “Attic Ventilation.”