Leaking skylights account for a large proportion of calls to local roofers. Not a huge surprise in a climate as wet and rainy as Vancouver’s. If you have skylights in your home or are thinking of having one installed, here’s some information to help you anticipate and prevent potential problems.
Causes of a Leaking Skylight
When it comes right down to it, skylights actually leak for a limited number of reasons.
- Poor design. All skylights are not made the same. Some are prone to failure due to poor joints and seals or cheap plastics flanges that break later on.
- Wrong one for the job. In the coastal climate of Vancouver, it is critical that a skylight be designed to accommodate varying temperatures, rain, snow and other factors. In some cases, a roof-hugging design may look better, but be ultimately more troublesome than one with a high curb allowing adequate protection from surging rain or snow and ice buildup around vulnerable openings. A good skylight should also be up to carrying snow loads and seals capable of withstanding immersion in melt water for indefinite periods.
- Leaks from other areas. Despite a drip or leak appearing around a skylight, the actual problem could be from a roof cap, vent flashing or other place higher up on the roof. Water can travel great distances along the underside of roofing, sheeting and rafters before finding an outlet.
- Improper installation. Even a great skylight design can be subverted by poor installation techniques. The installer needs to follow the proper steps required for each skylight model, and pay special attention to the flashing, seal and/or flange installation. This is crucial in helping to prevent problems with a leaking skylight.
- Age. All material things wear out eventually. Acrylic bubbles deteriorate faster than glass. During re-roofing, it is a good strategy to replace skylights of the same age as the roof. This will not only assure a cleanly installed roof, but head off problems from a leaking skylight that has expired too soon after a re-roof. Old and cracked flashing, dried out or damaged and cracked seals, and deteriorated joints and parts can become chronic sources of troublesome leaks.
- Condensation. While not an actual leak, this can be a nasty problem leading to unsightly and costly damage. Condensation usually occurs because of one or more of these three factors.
- Single thickness glazing. Condensation quickly forms whenever moist warmer air meets cooled window surfaces. A single layer of acrylic or glass offers very little insulation value and therefore no condensation protection.
- Failure of the seal in double-thickness layers. Glass skylights usually do not present this issue. Acrylic bubble skylights are notorious for their seals failing and condensation occurring.
- No or improper insulation of the skylight tunnel. Some skylights are installed where they must have a tunnel routed through the attic to join the skylight on the roof with the room below. It is sometimes overlooked that this tunnel should be insulated since it goes above the ceiling insulation layer and through the normally unheated attic. The walls of the tunnel can chronically drip condensation in cold weather.
Use a Skilled Vancouver Roofer to Avoid Leaking Skylight Syndrome
It is highly recommended that any homeowner wishing to install a new skylight or replace an existing one hire the services of an experienced Vancouver roofer. Money saved on a do-it-yourself project of this kind can easily be outweighed by the price of damage done to a house or its contents by a leaking skylight.
As a renovator Doug did many rot repairs which gave him a good understanding of where and why buildings leak, and how to prevent it. He realized the need for a different approach to roofing; one that educated the customer enough to make good decisions. With better trained installers and a quality inspection process Absolute Roof Solutions was born…” Read more.
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