Category: Typar
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By: John D. Wagner
Walking past a remodeling job recently, I looked at the structure, which was covered in housewrap with some siding already installed and said to myself: “There’s no seam tape and no window flashing. The housewrap has been ‘X’ cut and peeled back around rough openings. The application is substantially useless. When the mold hits, any warranty will likely be void.”
I can’t count how often I see housewrap installed improperly. Some contractors simply staple it up, overlap the seams 6 inches and start siding—which is wrong. Housewrap, also known as weather-resistant barrier, is designed to work as a system comprising the housewrap, seam tape and flashing so it performs well in four key areas: 1) moisture resistance, also called water holdout), 2) moisture vapor transmission, 3) surfactant resistance and 4) strength or tear resistance.
Housewrap resists weather, but the weather doesn’t know to avoid seams or rough openings. Weather assaults the entire wall, and the housewrap must be installed so it can balance resistance to air infiltration (wind) and water (mostly liquid that gets behind the siding). It must also allow diffused water vapor to escape from inside the structure. Why the need for high performance and such attention to detail during installation? The average house produces 3 to 6 gallons of water vapor each day, or 2,190 gallons per year. The moisture is often water vapor, diffused or driven through the walls by temperature differentials between the conditioned space and the outside air. But there’s water coming from the outside, too. Moisture in the form of humidity or liquid water as rain inevitably gets behind the siding.
If your contractor customers aren’t installing housewrap properly, it will admit and trap water as a liquid or vapor inside the wall, and the water creates ideal conditions for rot and mold. By not sealing the seams or flashing rough openings, water from outside will likely get into the wall. For your customers’ sake, you must underscore the importance of buying a housewrap system (tape, flashing and the rolls of wrap) and warn contractors that they risk system failure if they aren’t using all of the system’s components. You can’t expect standard sheathing underneath the housewrap to magically stop moisture, unless it’s a sheathing system specially engineered to act as a weather barrier. The sheathing will have an effect but, according to the Air Barrier Association of America, a typical 2,500 sq. ft. home has more than 1.5 miles of cracks and crevices, and water or moisture will find its way into those openings.
It’s about Balance
The best housewrap balances its ability to hold water out and allow the escape of water vapor from within. If the housewrap has low water holdout characteristics and results in high vapor permeability (vapor permeability is measured in “perm”), it will likely admit too much water. On the other hand, if the housewrap does not allow enough water vapor to leave from the inside of the wall (low perm), that trapped water vapor may condense within the wall, potentially leading to rot and mold. A housewrap with an exaggerated capability for water holdout achieves that performance at the expense of its ability to allow diffuse water vapor and vice versa. When evaluating what housewrap you offer on your shelves, keep these things in mind:Moisture resistance and moisture vapor transmission: Most building science research states that a well-balanced housewrap should have a perm rating between 10 and 20.
Surfactant resistance: A surfactant is a compound that lowers a liquid’s surface tension and degrades the water holdout capabilities. Your housewrap should have superior resistance to them.
Strength: The strength of a housewrap is determined by its resistance to tearing. With building cycle times running more than 120 days, remember that a housewrap functions as temporary siding subjected to the weather, especially wind and sun. Look for a housewrap that is engineered for tear-resistance.
In addition, look for a manufacturer’s statement about UV resistance. Finally, ask your rep how the housewrap enhances the thermal envelope. Independent studies by DOE and Energy Star show that housewrap, when properly installed, flashed and sealed as a system, can lower energy bills between 25-40%—all the more reason to take the manufacturer’s installation recommendations seriously.
The direct ocean front condo building shown is just ten years old. Had the correct housewrap, tapes and flashing been properly installed during construction, this expensive repair would not be needed.
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In today’s market, builders are always looking for that edge that will give them a leg up on the competition. At the same time, homeowners are always searching for products that will enhance their home’s value, while providing superior performance and peace of mind. One such product is NAHB Green Approved TYPAR housewrap and its family of TYPAR flashings and tapes. Together they form the “TYPAR Weather Protection System” which offers a 10 year warranty against damaging water infiltration. Water infiltration can lead to costly structural damage and unhealthy indoor air quality. This warranty includes materials and labor. The installer needs to use TYPAR housewrap, TYPAR flashing, TYPAR construction tape and install the housewrap with capped staples or capped nails. Equally important is for the installer to follow the window and door manufacturer’s recommended guidelines for proper installation. Proper integration of the fenestration with the TYPAR Weather Protection System will insure a successful project and a home that performs over time.
While there are an abundance of excellent performing window products in the marketplace today, without question, one of the most common in the Northeast is the Andersen 400 Series Tilt-Wash double hung window. For over 20 years this window has been filling openings in some of the country’s harshest environments. Proper installation is essential however, to the window achieving its design performance. Companies, like Andersen, subscribe to one of two installation systems. The first is the “barrier method”, which is designed to seal all four sides and prevent any water from entering the perimeter of the window. The second is the “drainage method” (pan system) and seals the side jambs and head jamb, while the sill sets into a panning system to channel any water out if it gets by the flashing system. In their instructions, Andersen subscribes to the “drainage method”. (See installation details @ www.andersenwindows.com; click on 400 series TW under “Service/installation” view pdf on Basic Installation”).
In their 11 page detailed installation instructions there are some points to note. First is preparing the rough opening. Proper cutting of the housewrap includes cutting across the head jamb and up at 45 degree angles at each corner. This flap will go over the head jamb flange as a final step and serve a critical function in shedding water away from the opening. Cutting the remainder of the opening is done by making a vertical cut down from the center of the head jamb to a point mid way down then at an angle to each corner of the sill. The side and sill flaps of housewrap are then wrapped to the inside and stapled off. Pans are available from a variety of sources. 9” TYPAR “Flex Flashing” serves as an excellent material to form a superior performing pan that is also very cost effective. By following Andersen’s step by step instructions, along with taping any vertical and horizontal seams with TYPAR Construction Tape (over lapping the courses of housewrap by six inches), you can be assured of a high performance, trouble free project.
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In today’s ultra competitive roofing market, one way dealers and their customers can differentiate themselves from the rest of the pack is by offering the end user a synthetic roofing underlayment instead of the traditional Type I (No. 30) or Type II (No. 15) roofing felt. Innovative synthetic roof underlayments offer numerous benefits that traditional asphalt saturated roof felts don’t. Unlike synthetic roofing underlayments, roofing felt is made of wood fibers, so it expands and wrinkles when wet. Often overlooked, roofing felt can be damaged by jobsite exposure, including UV, wind, and rain. This jobsite exposure often leads to rips and tears to the felt that need to be replaced before covering with shingles. Because of its non-organic construction, synthetic roof underlayments such as Surround by Typar are made of a high strength polypropylene material that’s rot resistant and lays flat during installation. The unique polyolefin coating on Surround produces a slip resistant surface while providing increased water resistance and longer UV resistance. Furthermore, the physical properties of Surround make it far lighter and easier to handle than roofing felt while making it as much as 10 times stronger than roofing felt. Not only does Surround meet ICC and Miami-Dade County codes, it’s also backed a by a 30-year limited warranty.
The primary function of a roofing underlayment is to provide a secondary line of defense against moisture intrusion under roof shingles, shakes or clay tile. As a secondary role, roofing underlayments also protect roof decks from moisture during construction and later when shingles may be damaged after a wind storm. The additional durability, strength, water resistance, and ease of installation of synthetic roof underlayments like Surround have caught the eye of roofing contractors nationally. Surround is a versatile solution that can be used under asphalt shingles, tile, shakes, slate, and metal roof coverings. This relatively new product will continue to represent a growing market segment of today’s Building Materials Industry.
Boston Cedar was honored with the 2009 and 2010 Fiberweb Distributor of The Year Award.
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