| More Information | Ventilation explained |
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Roof / Attic Ventilation
Roof top ventilation, which is technically attic ventilation, is a highly important element of roofing. Proper roof ventilation will increase the longevity of your roof.
Poor roof ventilation will vastly shorten the life of the materials. We see this scenario daily, roof systems failing far short of the material life expectancy. Had a very small investment been made when the roof was installed, adding proper attic ventilation, the roof would have lasted much longer.
Proper attic ventilation will extend the life of a roof along with reducing problems as it helps balance, or minimize the temperature differential between the air in the attic and the air outside. Simply stated; Proper roof ventilation will remove moisture and heat from the attic.
Problems caused by poor ventilationTrapped moisture and heat can raise energy costs by putting a load on your AC. It can also cause ice dams, damage to roof system and structural components. Not to mention, personal items stored inside the attic where temperatures can easily reach 150° F (65° C).
Trapped moisture (more of a concern in humid regions) causes condensation. Condensation that forms inside an attic can come from use of tubs, showers, washing machines, clothes dryers dish washers, etc. In extreme cases condensation can be bad enough to be mistaken for a leaking roof.
Other Condensation Concerns•Deck Deflection the deck of the roof can warp, deteriorate, become spongy (soft)and very dangerous to walk on. The adhesives used in the plywood can deteriorate or Dry Rot. This can happen happen over the course of several years, extreme cases can develop this problem in as little as two years. This occurs because one side of plywood decking / sheeting needs be able to "breathe" by being exposed to circulating air....no circulation combined with condensation...wood cannot "breathe"
•Rust; In humid regions water vapor condenses first metal inside the attic; nails, plumbing straps, straps holding duct work etc. Any uncoated metal will rust over time, this could cause the metal to deteriorate to the point of failure. Rusted straps on duct work could break allowing it to fall on ceiling joists, or worse yet, through a suspended ceiling or drywall.
•Mold, Mildew, Fungi; While the health concern regarding mold has yet to be medically proven, mold, mildew and fungi WILL cause dry rot. Dry rot does not not remain in a localized area, it will spread and damage any lumber that is effected.
Ice Dams
•Ice Dams occur when snow melts from the higher portion of the roof, then refreezes along the edges of the roof. Ice will buildup under the shingles causing damage, followed by leaks. Another more immediate problem arising from ice dams will occur when the water melting from the ridge of the roof puddles, or pools behind the ice dam where it will find it's way under the shingles, past the underlayment and into the attic. Ice dams can be avoided with proper ventilation, good insulation and air circulation, creating a "cool roof".
In some scenarios the architecture of the home will lead to ice dams being more prevalent on certain areas of the roof eves although there is proper ventilation and insulation. In cases such as this, the use of heat tape or heat element underlayment is useful and suggested along with installation of heat tape in the gutters and down spouts.
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