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WHY REPAIRS?

When budgets are tight and the roof is leaking – what else???


When you have the following conditions present on your roof-
we can assess your need for repairs!

BLISTERS
RIDGES
POUNDING WATER
L E A K S
ALLIGATORING
EXPOSED FELTS
CRACKED FLASHING DETAILS
BLUEBERRIES
PITCH POCKETS
SPLITS
WHEN YOU DON’T HAVE A ROOF PROGRAM IN PLACE!


Definitions of Some Conditions That Could Be Found on Your Roof:

Alligatoring: a result of the drying out and shrinking of the asphalt surface resulting in a “mud-cracking” pattern. The pattern is most pronounced in areas of exposed asphalt.  It is caused by the heat and UV rays of the sun beating down on the exposed asphalt surface.  If left untreated, the alligatoring condition can develop into splits in the roof membrane.  As the surface continues to shrink and dry out, cracks will develop down to the depth of felts and may stress-crack the membrane in cold weather.  These crack channels will allow water to penetrate and damage the roof system.

Bare felts: areas lacking in surface asphalt, mineral, granule, or aggregate due to wind and water erosion. Weathering causes the roofs surfacing materials to oxidize and wear away after a period of time.  Loss of protection from the surfacing material results in accelerated deterioration of asphalt (the roof’s water repellent) and felts (the roof membrane’s strength). Heat and UV rays dry out unprotected asphalt which then leave the bare roofing felts exposed to the elements. The exposed membrane will then absorb moisture and degrade through freeze/thaw or wet/dry cycles, causing premature failure.

Blisters: soft spongy pockets or swellings in the roofing material.  They occur between layers of felt or between the roof membrane and substrate.  Air or moisture vapour entrapped within a blister expands as the roof and outside air temperatures rise. This results in sufficient pressure to push the roofing felts upwards and apart.  Blisters may be ruptured by roof traffic, expanding frozen water, or hail (especially during colder weather). Some blisters may become so large as to affect drainage, which may then cause pounding water.  Laps could also be pulled apart, resulting in leakage. A ruptured blister will immediately allow water to penetrate and damage the roof system.

Blueberries: these are the result of dried out surface asphalt. They appear on the roof as small blue or black balls or berries. When the top pour of asphalt erodes to this stage, the roof system has lost at least 40% of it's waterproofing ability.

Perimeter Flashing Deterioration: expansion and contraction movement of the metal edge causes a sawing action that cuts into the perimeter flashing.  Moisture can then enter the roofing system and building.  Moisture entry will cause damage to the insulation and reduce its insulating properties.  It will also allow water to enter the building causing internal damage.

Pitch Pockets: metal protrusions that penetrate the roof system to allow conduits to run from the roof top into the building.  Movement from the protrusion can break the waterproofing compound, creating cracks.  Over time, the release of solvents from the compound can cause the material to shrink, leaving gaps along the edges of the pan and around structural support.  Water can enter through a defective pitch pan and find its way into the interior of the building. Moisture can also penetrate into the roof system leading to premature failure.

Ridges: these show up on the surface of built up roofs as linear buckling felt lines protruding upward through the surface layers of asphalt and aggregate. Ridges are formed by either thermal changes expanding and contracting the roofing felts or by gaps in the underlying insulation that allow vapour to migrate upwards through the roof system. Over a period of time ridges will grow and erode until they are stripped of their protective asphalt. These exposed ridges, through repeated weather cycling, will eventually crack and split to allow water into the roof system.

Splits: membrane splits are usually caused by building movement, ridges, and expansion and contraction.  Such movement can be caused by lack of attachment of one or more of the component parts of the roof system, or where the building itself generates movement.  Weak or inflexible membranes reach a point where they cannot accommodate further movement. At this time the roof splits open. The open split allows water to enter the roofing system, saturating the insulation, and causes leaks into the building.  If allowed to persist, the area of damage will expand.

Pounding: pounding water occurs as rain or snow melt water collects in large pools on the surface of a roof system. These pools begin to form because of two reasons: (1) roof drains are blocked or clogged with debris, (2) roof drains are built along side building support columns which maintain a consistent height while the rest of the roof system is built on a deck which tends to move and deflect under the downward pressure of weight. In both cases, roof depressions that collect and hold water will tend to grow in size as the added weight of the pounding water will continue to deflect the roof deck even further.  Pounding water has many negative effects on a roof system. The added weight can crush insulation to the point where it becomes a useless thermal barrier - this will cost you big money since your HVAC system will have to work longer and harder to maintain a comfortable interior temperature. In the winter pounding water will expand as it freezes. This expansion will weaken small imperfections in the roof system. Small cracks and tears will widen until they rupture to allow water into the building. Pounding water also accelerates the aging of a roof. The natural waterproofing oils in the asphalt will separate from the membrane if the system remains submerged under water for periods longer than 48 hours. And finally, a negatively deflected deck becomes a structural concern. The deck’s tolerances will only accept a limited amount of  weight and deflection before it becomes a candidate for a roof collapse. The roofing felts are not waterproof. They are a 100% wood fibre compound and left unprotected, will absorb water. Over a period of time, they ultimately rot, exposing the next layer of asphalt. This layer is installed at one third the rate of the initial top pour and its oxidation rate is much greater.  When it disappears the next layer of roofing felt is exposed and the cycle continues.

Additional Suggestions:

Many building owners could prevent costly replacement of their roofs if they would pay more attention to their flashing. If properly maintained, roof systems can last the lifetime of the building. Proper maintenance begins with the flashings.

At least 80% of all roof failures begin at the flashings. Flashing have greater exposure to the weather, and will begin to deteriorate before the roof surface shows any indication of disrepair.  To an expert, the flashings reveal the true condition of a roof system.




Copyright 2010 Global Roofing Services Inc.:  Toronto Roofing.  All Rights Reserved.