by United Roofing MN | Oct 4, 2011
Underlayment Requirements For Minneapolis Minnesota Underlayment is a material placed on the roof sheathing before installing shingles. It is usually a thin, black, paper-like material, often referred to as roofing felt. It comes in a roll and is usually 36” wide. It also comes in different thicknesses or weights. The minimum acceptable underlayment is 15# roofing felt. Underlayment may also be a self-adhering, rubber-like material. This type of underlayment is most often used at the roof edge and in valleys to help minimize damage from ice-dams. Many shingle manufacturers recommend their own type of self-adhering underlayment and where it should be used. Some local building codes and UL standards require that a shingle underlayment be installed. Underlayment shall comply with IRC Section 905.2.3 and its application shall be according to IRC Sections R905.2.7 and R905.2.7.1. Minnesota’s climate is considered severe with respect to underlayment requirements. An ice barrier is required and shall be installed as follows: • The ice barrier shall consist of two layers of underlayment (15# roofing felt) cemented together or a single layer of a self-adhering sheet. Whichever product is used, it must be installed parallel to and extend from the eave edge to a point at least 24 inches inside the exterior wall line. • After installation of the ice barrier, install remaining underlayment as follows: For roof slopes of 2 units vertical in 12 units horizontal (2:12) up to 4 units vertical in 12 units horizontal (4:12), underlayment shall be two layers of 15# felt. Starting at the ice barrier, install the first course of 36 inch wide underlayment lapping the ice barrier a...
by United Roofing MN | Sep 27, 2011
The Importance of Roofing Underlayment We select our roofing material carefully and one of the basics is that it has got to be waterproof. It has to perform that function, so why the heck do we need to spend extra money on underlayment? While the roofing material is indeed waterproof there are other factors that come into the equation. You could quite possibly void your roofing manufacturer’s warranty if you don’t use it. Regulators around the world require it. If you don’t use it you could be in trouble, but the regulations are there for good reason:- The roofing underlayment forms an additional waterproof membrane for the extreme cases that the roofing material itself can’t handle. Extreme wind blown rain, capillary action and ice dams around chimneys etc can let water past the main roofing material. Condensation. In humid conditions variations in temperature between inside the roof space and outside the roof can cause condensation on the inside of roofing material, causing rot in timber dampness and mildew in ceilings. Thermal efficiency. A good underlayment can keep hot air inside the home in winter, saving heating costs and it can keep hot air out of the home in summer saving on air conditioning costs. Choosing the Right Underlayment There are different categories of roof underlayment. The old faithful, roofing felt and its derivatives. Be careful here and check carefully the fire ratings of these materials and your own regulations. Felt itself, as in felt hats is a non woven material. The strands are aligned in a bonding material and pressed into flat layers. The original fibres were probably wool,...
by United Roofing MN | Sep 22, 2011
Roofing Contractors Minneapolis & St Paul MN All roofing systems are made of a number of different components: roof sheathing, underlayment, roofing material, roof intersections, flashing details and ventilation. Each of these systems must be installed correctly for the system to work as designed. Roof underlayment acts as water barrier installed underneath the roofing system. Essentially, it is a roof underneath the roof. It protects your roof from condensation that may form underneath the metal due to the differences in temperatures in the attic and outside. More Information On Felt Roofing Underlayment One of the most common mistakes being made today in the installation of asphalt shingles on new or re-roofing work is the practice of not using felt underlayment. Many thousands of new homes do not have felt beneath the shingles. This is a HUGE mistake! Remember, shingles rely on gravity to keep water from entering your house. It is very possible for wind driven rain to get underneath your shingles or to enter along valleys (especially when the valley shingles have been improperly trimmed!) Without felt Underlayment, you have no hope of stopping a leak. With felt, there is a possibility that the water will travel down the felt and not enter your house. Many asphalt shingles that are installed on residential roofs carry a Class A fire rating. This rating is given to the shingles by independent laboratories. The ratings are granted only when the shingles are installed as they were tested in laboratory conditions. The shingles are tested with felt in place under the shingles. As such, if felt is deleted on your job, the shingles...
by United Roofing MN | Sep 20, 2011
Residential Roofing Services MN – Roof Underlayment The correct roofing underlayment, also known as roofing felt is critical to any roofing job. You must use it! Roof underlayment acts as water barrier installed underneath the roofing system. It protects your roof from condensation that may form underneath the metal due to the differences in temperatures in the attic and outside. What Function Does Shingle Underlayment Serve? Underlayments extend the life of a roof by protecting it against leaks. An underlayment, commonly known as roofing felt, will: Protect the roof deck from moisture prior to shingle application Provide a degree of backup protection in the event water gets under roofing shingles. Extend The Life of Your Roof With Roofing Underlayment Some local building codes and UL standards require that a shingle underlayment be installed. Ask your Minnesota roofing contractor if this is the case in your area. Also, some manufacturers offer a special underlayment product which prevents leaks caused by water backup from ice dams—a common condition in our Minnesota winters. Protection against ice dams can be obtained by using a waterproofing shingle underlayment at the eaves or lower edges of the roof, in addition to installing adequate ventilation and proper insulation in the attic floor. (See Prevent Roof Damage From Roof Snow and Ice Dams) Ask your roofing contractor about these specialized underlayments. Underlayment & Ice and Water Protection The entire state of Minnesota requires special eave protection that consist of at least two layers of Underlayment cemented together of a self-adhering polymer modified bitumen sheet, shall be used in lieu of normal Underlayment and extend from the eave’s edge...
by United Roofing MN | Sep 1, 2011
Roof Flashing Most leaks take place around roof penetrations. They need to be installed correctly and checked periodically. Did you know that 90% of roof leaks are caused by improperly installed or deteriorated roof flashings? The other 10% of roof leaks are usually the result of improperly installed windows or gutters which can cause water to leak along and inside walls of your home. Roof Flashing Done Right If you’re collecting dripping water in a pot beneath your roof, you may want to inspect the roof flashing. Anywhere surfaces intersect on a roof is a prime spot for water seepage. Flashing provides the extra protection these spots need. These problem areas include the edges of skylights and chimneys, soil stacks, vent fans and roof valleys, as well as the intersection of the roof deck and dormer walls. Most flashing is made of galvanized metal, but DIY’ers may prefer aluminum flashing because it’s easier to bend. Most flashing products are designed for easy installation, and if the material is installed correctly, then your roof shouldn’t leak. However, from time to time, the nails that fasten flashing work loose, or the flashing material pulls away from seams and joints and requires maintenance. Here’s a look at some general principles of roof flashing that will help guide you through a proper repair or replacement—or even new construction. Roof Design All roofing systems are made of a number of different components: roof sheathing, underlayment, roofing material, roof intersections, flashing details and ventilation. Each of these systems must be installed correctly for the system to work as designed. Common pitched roof systems rely on...
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