Maryland Roofing Underlayment And Flashing
Acting as a second line of defense against moisture damage, roofing underlaymentprevents any water that gets past the roofing and flashing from compromising thesheathing and causing leaks. For additional protection, membranes are often usedbeneath the underlayment in areas prone to leaks, such as valleys, and help seal holescreated by roofing nails. The underlayment choice depends on your roof ’s pitch andother factors, but the standard is roofing felt (often called tar paper or builder’s paper).Historically made from paper fibers saturated with asphalt, roofing felt today utilizesfiberglass to resist tears.
The felt’s thickness is measured in pounds per square (one squareequals 100 square feet of roofing material); 15- and 30-pound felt are most common.Thirty-pound paper lasts longer and provides better leak protection. There are fewalternatives to builder’s paper for roofing underlayment. Look for recycled content.During installation, make sure your roof ’s sheathing is dry–the waterproof underlaymentcan trap moisture and damage sheathing.Breather membranes are uncoated spun-bonded polypropylene multiple ply barriers that perform especially well for metal, tile and wood shake roofs. Allowing potentially troublesome moisture to escape, they resist tears and are even strong enough to be use das temporary roofing.
Flashing and Drip Edges Another important barrier to leaky roofs is flashing. Placed in valleys and wherever chimneys, ventilation or skylights penetrate the roof, these bent metal pieces form a watertight barrier spanning unlike materials or other vulnerable areas. You can sometimes reuse existing flashing if it’s in good condition; old galvanized flashing can berecycled. New flashing is usually made from galvanized steel, and less often from copperor lead–all of which are harmful to water quality and human health.
Additionally, leadand copper production processes cause significant pollution. For durable flashing thatdoes not compromise environmental or human safety, consider powder-coated aluminumor steel, or stainless steel flashing. Although more difficult to install than galvanized, stainless steel flashing lasts much longer, and is both reusable and recyclable. Drip edges are installed along the roof’s perimeter to keep water from tracking under the eaves where it can damage the roof and siding. All roofing systems should include some sort of drip edge component. The material choices are similar to flashing, with aluminum being the most readily available and ecologically-friendly option. One fairly new innovation involves products that combine a drip edge with roof ventilation. Available in plastic and rolled aluminum, they pair with a ridge vent to provide necessary air flow, while guiding water into gutters.
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