Rot Repair Roofing & Roof Health

Rot Repair Roofing & Roof Health

Roof repair, rot repair, roofing

The stages of rot repair during a Calgary roof replacement

Rotten wood on the roof deck can add extra cost to your roof replacement. Approximately 30% of houses will have deteriorating wood under the shingles that must undergo rot repair roofing before any new roof product is installed.  All rot is caused by water, which is generally introduced to the roof deck under 4 common conditions:

  • Eavestrough. During the winter ice & snow can build up in the eavestrough.  As the ice and snow piles up it will contact the roof deck underneath the shingles.  Due to a wick effect water can be drawn up to 10″ away and rot can begin to form.  In more extreme cases the wooden fascia & soffit can begin to rot.  Proper application of drip edge virtually eliminates this problem and serves to ensure that water drips into the eaves trough and not behind it.
  • Valleys, Chimneys, Vents, and Skylight Flashings.  Flashings are normally made of galvanized metal and are largely impervious weather,  If a leak occurs around metal flashing it is because it has not be installed correctly.  Often times careless roofers will try to fix their poor flashing job using cheap roofing tar, which when exposed to UV light will slowly degrade.  Eventually it offers no benefit and water will begin to penetrate the roof.  On most older homes there is no metal valley installed at all, and leaks in this area are common.
  • Improper Ventilation.  Perhaps the most insidious form of water damage, moisture buildup in the attic can wreak havoc on a house.  During cooler weather warm, humid air will migrate from the living area and stagnate in the attic.  Without proper ventilation to carry it away a layer of ice will form on the trusses and underside of the roof deck.  When the weather warms up the ice will melt and water will soak in to the plywood.  The layers of the plywood will begin to separate in a process called delamination.  This can mean entire sections of the roof must be re-sheeted – which can become quite costly.  In some rare circumstances black mould can form inside the attic and can affect the health of those living in the home.  Read more on vents and ventilation by clicking here
  • Old Wood Shake.  As wood shake deteriorates the asphalt felt paper underneath can begin to form holes.  Small amounts of water can soak into the plywood underneath.  Often times there is not enough water to show inside the home, but the sheeting will begin to rot and form mould.  Approximately 20-30% of wood shake roof replacements will have this kind of rot.

Rot repairs roofing is typically quite straightforward.  It is very uncommon to find structural damage such as rotten rafters or rotten trusses.  Standard procedure is to cut out the affected sheeting and install new product.  In most cases it is hard to predict rot, and it must be deal with on an as-needed basis.

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