1) Improper Ventilation
Roofing contractors should know enough about attic ventilation to vent your attic properly. Requirements are 1 square foot of ventilation for every 300 square feet of attic space with a combination of intake and exhaust vents. Intake vents are normally in your soffits and exhaust vents are on top of the roof.
If the roof isn’t properly ventilated and your shingles begin to fail before their time, they won’t be covered by the warranty. Improper ventilation may reduce your warranty to 10 years.
2) Installation Over Non-Approved Roof Decking
Your roofing contractor should be able to tell what type of roof decking you have and if it is approved to install shingles on. Some approved roof decks are plywood, OSB, and wood board sheathing at minimum thicknesses. Some decks like large woodboard sheathing may cause bucking so extra precautions should be taken.
Other roof decking materials are “permission-required” decks and must be installed to manufacturer specifications and need special fasteners to not void the warranty. Other roof decks like Cementitious wood fiber board, insulation boards and gypsum are not approved and require approved decking to be installed on top of them although these are not so common on houses.
If the roof contractor doesn’t properly prep the decking after tearing an old roof off, this too can void the warranty especially if there are existing nails sticking up that pierce the shingles.
Tearing off everything (even old felt paper) to be able to see the roof decking clearly will help prevent these scenarios. Taking the time to check for and pull all existing nails or pound them into the decking and taking every precaution necessary to ensure the warranty stays valid is something every roofing contractor should strive for.
3) Improper fastenings
One of the most common causes of shingle failure is improper fastening and this is not covered by the manufacturer warranty.
If not fastened properly your shingles may blow off, if this happens you will be responsible for going after the roofing contractor or pay for it yourself. There are several ways fastening can void your shingle warranty.
1. Over-driven nails rip through the shingle and make it very easy for the shingle to be blown off by gusts of wind.
2. Under-driven nails will hold up the shingle above, preventing it from properly sealing down to the shingle below. This can let dust in which will prevent the sealant from activating, and allows wind to catch the shingle and tear it off.
3. Nails that are driven crooked into the shingle cut into the shingle on one side of the nail, while the other side holds up the shingle above. These two things combined makes for a perfect opportunity for shingles to be blown off by wind.
4. Nails that are too short. Nails must be long enough to penetrate through the shingle and all the way through the sheathing. If the roof decking is thick, nails must penetrate up to 3/4″ into the wood.
5. Too few nails. Each type of shingle requires a certain number of nails to be used per shingle, the average is 4 nails placed evenly.
6. Improper placement of fasteners. Each type of shingle also has a “nail line” where nails are required to be placed to achieve the designed performance. If the nail line is missed, then blow-offs are more likely to occur and are not covered by the manufacturer warranty.
No one really wants to go through the process of having to check up on their roofing contractor. The best way to avoid costly mistakes such as these, is by doing your homework and researching the contractor you are considering hiring. Hiring a company like Atlanta Roofing Specialists, who includes a 10 YEAR WORKMANSHIP WARRANTY with their roofs and with over 20 years handling manufacturers specifications and experience in providing quality service will help ensure you will never see these types of problems.
Save yourself the trouble of wondering if you’re contractor is “up to snuff”, call Atlanta Roofing Specialists today for your Free Estimate at 770-419-2222.