Roofing

Roof, chimney and skylight flashings need regular maintenance to prevent leakage.

Lack of maintenance to roof components may significantly reduce their life span or allow leakage. Read the maintenance section provided. Where roof coverings or flashing areas need repair, there may be underlying, unseen damage to the sheathing or to the roof structure.

We recommend an annual inspection and tune-up to minimize the risk of leakage and to maximize the life of roofs.

The basics…

The roof protects the building from water, snow and sun.

Slope

The roof pitch is measured by considering how far it goes up (rise) against how far it spans horizontally measured from a plum line through the centre of the ridge (run). Always use twelve feet as the run, so a roof that goes up six feet (over a distance of twelve feet) would be said to have a 6:12 slope.

Roofs with a rise/run ratio of 4:12 down to 2:12 are considered to be ‘low slope’ and need special shingles or other treatment. Roofs with a slope of 2:12 or less are considered to be flat.

Roof Coverings

Asphalt shingles are the most common roof covering for sloped roofs, followed by metal sheeting. Cedar, terra cotta, slate or concrete shingles are also available.

Flat roofs have a waterproof membrane, usually made of asphalt, tar, PVC or rubber. The gravel seen on many flat roofs protects the tar, asphalt and so on from the UV rays of the sun. It has nothing to do with waterproofing.

Semi-Detached & Townhouses or Row-houses

Properties which have adjoining roof surface will also require monitoring of these adjoining surfaces. A neighboring property with a roof in poor condition could develop leaks which may migrate beyond the property line which could cause damage although the roof cover on your side may be new.

Life Expectancy

Climactic changes such as increased ultra-violet light and air pollution have drastically reduced the life expectancy of most roof covering materials

Asphalt shingles: 15 – 20 years depending on the climate and proper ventilation. Manufacturers’ claims for 25 or 30 year shingles are not always substantiated in the real world.
Metal: 20 – 50 years – but you may have to do some maintenance such as repairing seams or painting.
Wood shakes: 30 – 50 years.
Wood shingles: 15 – 20 years.
Concrete or clay tiles: 50 – 100 years – but these are very heavy and need additional support for the roof structure.
Flat roof: 10 – 35 years (depends on material)
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Ice Damming

Ice dams are caused when inadequate or poorly installed attic insulation or major air leakage allows heat from inside the building envelope to escape through the roof and cause snow to melt on the roof. The water runs down the roof until it meets the colder overhang, where it freezes.

Subsequent melting water, trapped behind the dam, builds up until it seeps under the shingles and penetrates the roof. There is a good likelihood that leakage will result.

Installing tarpaper and/or ice and water shield when repairing or re-roofing generally prevents moisture penetrating the attic spaces. To resolve the problem on a more permanent basis, improve attic insulation and ventilation, especially at the eaves. In extreme cases – heating cables are a temporary fix.

Do not walk on roof shingles during the winter months in very cold climates. Resist offers from roving bands of snow clearance contractors. Few residential roofs are damaged by snow loads and walking on the shingles when they’re frozen will cause significant damage, which won’t be visible till spring. Likewise asphalt shingles can be damaged in hot weather by walking on the roof covering thereby removing the stone granules.

Flashings

Flashings are the materials that are used where necessary to prevent the entry of water through joints between materials. Flashing should be used at the junction of roofs, walls, chimneys, over window and door openings, in roof valleys and on other critical areas. Flashing plays a major role in protecting your house from water penetration. Failure to maintain these components can result in serious damage to the interior of the structure. Failure to perform regular maintenance for skylights and solariums, or add-on spaces can result in water penetration and damage.

Chimneys and flue pipes

Chimneys and flue pipes are used to discharge the gasses that are produced when we burn fossil fuels (gas, oil, wood and so on) to heat our homes or heat water. Chimneys are designed to withstand significant temperatures, (above 1,200 degrees Celsius during a chimney fire) and the constant heating and cooling associated with thermostat controlled devices.

It’s essential therefore that all chimneys and flue pipes are examined and maintained annually. This may only mean having a licensed chimney sweep come once a year. We recommend that all chimneys are cleaned and examined as soon as you move into your new home and before you use any wood burning devices.

Liners

Flue liners are the metal, cement, terra cotta or clay pipes, used to protect the exterior part of the chimney and the interior of the house from fire, heat and acids.

Damaged flue liners are a potential fire hazard. Any damage, rust or other deterioration must be repaired or the unit(s) replaced immediately. Gaps or openings in the flue liner can also cause damages.

Many oil burning devices do not have stainless steel flue liners. Many jurisdictions now require this feature. If your home happens to be in that geographical area, you may find that your oil supplier will refuse to supply oil until the liner is installed.

Flue pipes must be kept clear of roof materials to prevent fire. The chimney flue should be high enough above the roof to avoid downdrafts.

This is a guide to recommended clearances.

Trees and vines

In some areas, its popular to allow vines or other foliage to grow over and around the exterior of chimneys and flue pipes. In most cases where the vines grow near the top of the chimney, they present a significant fire hazard and should be cut back to clear the top by at least three feet.

Never grow vines on siding, stucco or over roof areas. The roots will penetrate the exterior, causing damage and creating a potential for leakage.

Trim trees that overhang roofs so as to create a six foot clearance. Extreme caution is required in trimming near overhead electrical power lines.