General Guidelines and Helpful Tips from the the State of Minnesota – DOL
The 2015 Minnesota Residential Code adopts the 2012 International Residential Code (2012 IRC). Roofing materials must be installed in accordance with Chapter 9 of the 2015 Minnesota Residential Code and the manufacturer’s installation instructions.
Building permits are required for re-roofing existing dwellings. Building permit fees are established by the municipality. Building inspections are performed at various stages to verify code compliance. Permit costs and required inspections can be obtained by contacting your local department of building safety.
Frequently Asked Questions
Do I need a new roof? How old is it? A roof that has been properly installed, ventilated, and has not been damaged can last 20 years or more. An inspection of the roof should be done periodically. Look for cracks, curled or cupped shingles, worn mineral coatings, exposed nails, previous patches, holes and exposed underlayment or sheathing.
Does the roof leak? If the answer is yes, it is necessary to determine why. If you have inspected the roof and it looks sound, the problem could be roof flashing. Many roof leaks are result of bad or misapplied flashing. You should spend time in the attic looking for water stains, particularly around vents, chimneys and vertical wall elements above the roof. Flashing can sometimes be replaced or repaired without installing a whole new roof.
Do it myself or hire a professional? This is a question only you can answer based on your skill level and time. An asphalt roofing project can be successfully accomplished by the homeowner if you take the time to become familiar with the roofing procedures. Be sure to plan your project around the weather and allow enough time to get a proper cover on the roof before it rains. Steep-sloped asphalt roofs and those with multiple valleys can present special problems, so be sure you have the right equipment and skills before undertaking this type of roofing project. Other types of roofs such as wood shingles, shakes and clay tile normally require special skills for installation. If you decide to hire a professional, be sure the company is a state-licensed contractor or roofer.
Should I overlay the existing roof or tear off the existing shingles? There are two options available for re-roofing installations. One would be to tear off the old roof before applying the new one. The second would be to lay new shingles over the existing roof. Roofing materials are heavy, so multiple layers can affect the ability of a roof to hold the weight of winter snow. An overlay can be the less expensive option. However, it is not necessarily always the best choice. There are advantages to tearing off the old roof before installing a new one.
• If there are any defects in the roof deck, they will be revealed when the roof is torn off. These defects should be repaired before applying the new roof. If condensation problems exist in the attic, they too will be revealed when the roof is torn off. Properly designed attic ventilation can then be installed in order to help eliminate such problems.
• When the old roof is torn off, an ice-protection underlayment must be installed before applying the new roof. This will help prevent ice damage.
• Tearing off the old roof and starting with a clean deck before re-roofing may result in a smoother finished-roof system.
• Tearing off the old roof will typically result in a longer roof life than when the roof has been laid over. This is because they are installed smooth over sound material and have new underlayment installed.
Recovering versus replacement? New roof coverings shall not be installed without first removing all existing layers of roof coverings where any of the following conditions exist:
• Where the existing roof or roof covering is water-soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing.
• Where the existing roof covering is wood shake, slate, clay, cement or asbestos-cement tile.
• Where the existing roof has two or more applications of any type of roof covering.