From our many discussions with contractors over the years, we’ve learned that roof-over installation introduces an increased risk of workmanship errors. Moreover, a tear-off will reveal defects in decking that might otherwise go undetected. We have also learned that a growing number of contractors recommend a tear-off to their customers because they believe that a
The roof deck is most vulnerable to leaks where it meets a vertical wall, at penetration sites such as a soil pipe or chimney, or at changes in slope such as at a valley, saddle, mansard, hip, or ridge. This vulnerability is due to: Deferential movements (e.g. the roof deck moves but the chimney does
Many shingles manufacturers do not require that shingle underlayment be used under their shingles for the standard shingle warranty coverage to be in effect on slopes of 4/12 and more. However, when we look at the performance of the roof system a as whole, underlayment has a legitimate role to play. Underlayment is considered to
On slopes below 4/12, down to 2/12, the risk of leaks is great, caused by phenomena like wind-driven rain and capillary action that can make water flow uphill, or by the backup of water behind ice dams. To reduce this risk, a redundant system – called shingle underlayment by its manufacturers – is applied beneath
Roof systems go way back. The asphalt composition shingle is a modern version of a shingle system invented as far back as the Egyptian dynasties, but no one can be sure of its origin. Wood shingles and shakes were probably the first shingles used in America by the colonists who brought the shingle concept from
Cracking Through Reinforcement Depending upon the style of shingle, the normal weathering characteristics described earlier may be a sign of more serious problems. For example, cracks across a typical three-tab shingle may be a sign of a weak reinforcement. This type of cracking threatens the waterproofing integrity of the roof and needs to be addressed
Just as the human body ages and changes appearance over the years, so too will a roof. Due to the severity of the roof environment, even a one-year-old roof may look different from a roof that was just installed. While cracks or blistering may first be noticed at close range (as from a ladder when
When a new roof was installed, friends and neighbours may have remarked how it enhanced the beauty of the home. However, research indicates that aging begins soon after the shingles are installed and progresses rapidly during the initial curing phase of its life cycle. During this stage, granule loss may occur, small blisters may develop
You may be asking yourself, “What can I expect a roof to look like as this aging process takes place?” One or more of the following conditions may occur over time: Curling As the asphalt hardens over time, the granules which were once securely embedded begin to break away. Occasionally you may have seen the
Consider the conditions a roof must endure. First there is the intense heat of the sun, which scorches the surface of the roof and raises rooftop temperatures 50º – 70ºF above ambient temperature. The sun’s rays are relentless, especially during the early afternoon hours. In addition to heat, the sun is the source of ultraviolet