Home Inspection Information Series

The question most asked by resale home buyers (after does the basement leak) is does the roof leak. Roofs are exposed to tremendous environmental stresses - rain, snow, ice, sun and extreme temperatures. Eventually, the materials wear out and require replacement to keep your house dry. A typical shingle roof will require replacement after 15 years. Depending on your particular situation, shingling may last for a shorter, or longer period.

An annual inspection is required to ensure that the roof is fulfilling its task. Special attention should be paid to the metal flashings where roof sections join each other, house walls and around chimneys. Different rates of expansion and contraction of house sections put a large strain on metal flashings.

Shingles should lay flat. Look for curling, broken or missing shingles. Shingles that do not match in colour, as well as patches of black roofing tar are both indicators of previous repairs.

Metal flashings should lay flat, without signs of tears or buckling. Around projections such as chimneys, flashings should be tight to the vertical surface and well caulked around all edges.

Fact: A common cause of leaks is from cracked or damaged chimneys. Look for loose brick, cracked mortar joints, and a solid metal or concrete cap on top. All are key components to prevent water entry.

Does the roof leak?

Look for water stains on the inside ceiling - or signs of a fresh ceiling paint job that could be hiding stains.

Look in the attic for water stains on the beams.

From outside, look for sags in the roof surface. Beams exposed to water can weaken and sag under weigh loads.

These indicators do not necessarily mean the roof leaks now. Water staining could have occurred many years ago. A professional home inspector or contractor can assess if a current problem is present and what needs to be done to fix it.

About ice build up on roofs:

Ice build up along the eave of a roof can result in an "ice dam" forming, blocking the free flow of water from the roof.

Ice occurs when snow on the roof melts from sunlight or heat escaping from the house. As the water reaches the cooler edge of the roof, it re-freezes. This can be an indicator of poor insulation in the attic, or insufficient ventilation in the attic space. Ice dams can also occur during warmer, sunny winter days or during period when the temperature is warmer during the day and cooler at night.

The best protection is to install an ice shield next time the shingles are replaced. An ice shield is an impervious membrane installed along the edge of the roof that provides a secure water barrier under the shingles.

When re-roofing, ask your contractor if his quotation includes an ice shield.

Caution:

Shingles can become soft in hot weather, and brittle in cold weather. Minimize walking on the roof during temperature extremes. Don't chip ice from a roof - you will do more damage than good. Roofs and ladders can also be very slippery. Your safest call would be to a roofing professional who has the knowledge and safety equipment to assess and correct your roof problems.