Environmental (green) issues, such as sustainability and cool initiatives, are also covered. Underlay support Underlays must be supported either by polypropylene tape, or 0.9 mm minimum galvanised steel wire mesh. More Information: See How to Install Metal Roofing Fasteners. Use your judgment to determine spacing per your geographic location, weather conditions and of course your local building codes. Nemes says he was the first to bring European manufactured synthetic roofing underlayment to North America in the 1990s. Over time, condensation can affect more than just your roof. The key is the thin breathable film between the layers of non-woven.”. Thereof, how far apart should purlins be? Our products may be used as a carrier for plants, or seed for pre-vegetation prior to assembly on the green roof,” he adds. Finally, when you do not completely remove the roof and attach the panels to roofing shingles, imperfections such as waves and dips in the metal will be more clearly visible because of the need to fasten them tightly to the existing shingles. Consequently, the most feasible option might be to use fiber board to fill open spaces between the purlins. “Our products are used all over the country wherever there are temperature swings. “Typically under metal roofs the nylon products are used but some customers prefer our polypropylene products. In most instances, a structure can only withstand a maximum weight of 10 pounds per square foot so you should be good to go as metal roofing is not very heavy. You also need to install spacers close enough so you don’t have oil canning, and to eliminate problems if someone needs to walk on the metal sheathing.”. Consequently, Fabral discourages using this method. If your patio has open beam architecture, and is designed to have a roof consisting of structural metal panels (that is, the panels attach directly to the beams without any sheathing) then you don’t need an underlayment. If choosing this option, it is important to note that one layer of shingles weighs from 2.4 to 3.2 pounds/square foot. It’s also important to make sure you’re using the right plywood for the job. Z Shaped Purlin: This type of z purlins is much stronger than C purlin and often used at joints and overlaps with each other. Colbond started out in subsurface drainage and sound control, then moved to roofing and green roofing products. Breathability means that moisture becomes gaseous and penetrates material based on the differential between the inside and the outside pressure. I can't afford to deck with 5/8 or 3/4 ply and pay upwards of $150 a square for structural panels. First, you can pull back the shingles to get to the existing substrate, which is a costly effort. Decking must be ply. Ours is adhered directly to the steel so you don’t have moist air migrating through our fleece through the steel. Place corner pieces where panels will meet bends at the edge of the roofing. It works for residential and commercial and is more expensive upfront, but if you consider the manpower and material needed to create space, this comes out the same and can even save money,” Nemes says, noting that these synthetic roofing underlayments have been in Europe since the mid 1980’s without a problem with moisture penetration. Underlay shouldn't be necessary if done correctly, and the ceiling/attic area is sealed from indoor condensation. Roll Self-Adhered Roofing Underlayment (225 sq. Two other types include: SBS Modified Bitumen, peel-and-stick underlayment that will not allow moisture to penetrate the underlayment; and Anti-Con, which absorbs the same way but is applied to the roofing panel by the manufacturer before it gets into the field. In the early 2000s, there were a handful of synthetic underlayment products all trying to wrestle a sliver of the market away from asphalt felts. If your building will have a finished interior or will be heated and cooled it may be worth considering one of the methods that use an underlayment of OSB Sheathing and Roof Felt. Newsletter/Ezine Sign-Up        Download Supplier Directory Listing Form      Advertising Opportunities      Contact Us, Design And Build With Metal has information on metal roofing (standing seam and batten seam, shake, tile, shingle, corrugated and screw-down roofs); metal wall cladding products (ribbed, smooth faced, insulated metal panels, aluminum composite panels, and curtain walls); metal buildings (pre engineered steel, wood post frame, hangars and self storage); insulation; doors; paint coatings; and many related products (including roof accessories like snow guards, screws and vents). But the highest use is with metal roofing. No matter the roofing material, preventing or minimizing condensation can be achieved with careful design of a building’s roof system including the use of vapor retarders, insulation, ventilation, or moisture barriers. Screw fasten the purlins using fasteners directly screwed into the trusses or rafters. From the 2012 IBC (International Building Code) Table 2304.6.1 – over framing spaced 24 inches on center, 7/16” OSB fastened with 8d common nails six inches on center at the edges and in the field will support a maximum design wind speed (Vult) of 110 mph (miles per hour) in Exposure B or 90 mph in Exposure C. … Therefore it will not allow moisture to go both ways, as the gaseous moisture will always travel from low to high pressure. These are large boards attached to the rafters and purlins of your roof which serve as structural support, barriers between the roof and the lower parts of the substructure and material to attach your underlayment to. If looking for a roof with a longer life span, aluminum is your best option. 5 Either way, we support our customers with training and with workshops for contractors.”. Some good choices for aluminum roofing include the Grandrib 3, Grandrib 3 Plus, Alutuff or Alutuff II metal panels. “We partner with companies that market products to specific construction or industrial related customers. Designed by Elegant Themes | Powered by WordPress, Please call us toll-free at 1-877-833-3237. with any questions or quote needs! The product he currently distributes is the nail down RoofAquaGuard UDLX. x 75 ft. In addition to metal panels and metal trim, we also carry a full complement of fasteners, clips, underlayment, 1×4 purlins (and other structural components), tools, skylights, R-foil radiant barriers, and more. Underlayment must also act as a secondary weather barrier in case the roof fails. This is most easily done by getting into the attic and seeing if there are any water damages sheets of decking. Components like ridge caps, interior gutters and other parts that are prone to cause condensation problems can be covered with CondenStop too. Matthew Bouril says: June 20, 2019 at 11:48 pm. When the temperature of a metal roof drops below the dew point, the CondenStop fleece will absorb and store the condensing water vapor. On a sloped metal roof there is a vent at the bottom to allow air in and natural convection takes air at the top out,” notes Wingfield. They are installed on top of the roof rafters with a felt underlayment or vapor barrier installed on top. They give added support to the roof and also provide a nailing surface for the end panels and drip … However, rigid insulation such as fiber board should not be used on the entire roof or as a material on which to fasten roofing materials. If there are gutters installed on the eaves, the eave flashing should be installed to overhang the lip of the gutter by about 1/2-inch. It is also resistant against problems like acid rain and corrosion. This lets any condensation on the underside of the metal roof evaporate. This should then be followed up with galvanized steel hat channel (preferred method) or 1” x 2” furring strips. Yellow Pine wood purlins Design Wind Pressure Fastener Pattern Fastener Spacing 1x4 Wood Purlin Spacing 1x4 Purlin Screw Spacing into Plywood -71.0 psf Type A 24 " o.c. This product takes away that step and makes it faster and easier to install. Reply. Additionally, wood shakes are often uneven and thus may also provide an unacceptable surface on which to lay your new metal roof. CondenStop is delivered in coils of 2100 square feet with a diameter of about 40 inches. When you put on a metal standing seam roof, or architectural panels, you need to create a space between the deck and metal panels to allow airflow to remove the moisture. Yellow Pine wood purlins Design Wind Pressure Fastener Pattern Fastener Spacing 1x4 Wood Purlin Spacing 1x4 Purlin Screw Spacing into Plywood -63.5 psf Type A 24 " o.c. You can also choose to install the metal roof over a Titanium underlayment. This effectively gives it a way to drain out and dry so the moisture doesn’t ultimately go in and cause a leak or cause the material to rot.”. Grace Ice and Water Shield 36 in. http://www.albertsroofing.com/Tin Roofing photo_gallery.htm When you have a standing seam roof placed directly on underlayment there is no space between so our product won’t work there. It is akin to cedar … In extremely hot temperatures, the asphalt may bleed causing residue to be on the worker’s shoes and potentially on the new roof. The first is to use a self-adhesive underlayment (i.e., ice dam protection) over the entire roof. Although adding a metal roof will add dead weight of only 0.8 to 1.5 pounds per square foot, it is crucial that you figure the weight capacity before determining whether it is safe to install the roof on top of another. Allan Wingfield AIA, Product Manager, Colbond Inc., Enka, NC, offers other solutions. However, if the existing shingles are rotting or deteriorating, it will be necessary to remove these shingles, to at the very least, make an assessment of the underlying structure to determine its safety. To help evaluate solutions, we asked some experts in condensation control products to offer their different views on how to prevent or resolve the issue. It’s an all-in-one product called Dry-Tech that we exhibited at METALCON.”. over the purlins before applying the metal. The foil is removed before roll forming and the steel is corrugated together with the fleece product. This type of assembly is designed to dry to the interior, so the assembly should never include an interior polyethylene vapor barrier. This insulation should meet the standards for proper thickness, R-value and provide a good vapor barrier while not being too thick or bulky as that can cause the metal roof to fit improperly. 24 for siding. Doesn't provide the flattest surface for the metal roofing to be installed over, each course of shingles is about a 1/8″ higher than the course just below it. Left untreated, unwanted moisture can damage wood and cause corrosion of metal decking, roof panels and fasteners in the roof structure. Before considering this option however, one must first research their local zoning and code restrictions relative to roofing options. Metal roofing offers an excellent option for replacing these standard roofing materials at the end of their lifespans. “They are stronger than saturated felt, which usually breaks down due to UV and does not last more than 15 to 20 years. Marcel Konijn, Sales Manager Construction, Lantor/CondenStop, Netherlands, adds another perspective. Plywood underlayment is typically needed when a floor material must have a very smooth, flat surface. Use 1 1/4-inch nails to cover the outline of the roof with strips of metal eave flashing, also called edging. This underlayment protects the decking or old shingles from any condensation which may occur on the back of … “With our product we are not trying to prevent condensation but to control it through the use of very highly absorbent fleece that is adhered to the interior side of the steel panels at the panel manufacturer’s site. “Putting purlins on the roof is time consuming and sometimes not desirable. Typical roofing construction will last somewhere between 5 and 20 years. In the cooler times of the year when metal is cold the warmer moisture in the building moves into the attic, hits the metal roof and condenses on the underside. Some three-dimensional mats go over any underlayment material. If weight allows and the under roof is in decent condition, you may be able to save on the cost of a tear-off. Other three-dimensional materials are attached on the top of the underlayment; these are usually roll goods that are either breathable or non-breathable.”. There are two ways to do this - put in firring/nailing (though nails are not used any more for this) strips or purlins (in steel frame construction) on the roof to support it, or place the metal roofing directly on a flat surface like foam insulation board or the roof sheathing (with roof water barrier in the correct position in the layer). 24 " 12 " -101.0 psf Type B 24 " o.c. Should you first remove the shingles, you will still need to install the underlayment or 30 pound felt. This includes roof coverings such as shingles, slate, or wood shake shingles. Traditionally, metal roofs have used standard 30-pound felt paper underlayment. If going this route, make sure your roof deck is in good shape. ft.) GCP invented fully-adhered roofing underlayments GCP invented fully-adhered roofing underlayments more than 35 years ago. Underlayment and Metal RoofingI often get asked what the importance is of underlayment beneath a metal roof. 24 " 6 " Installation Over an Existing Roof Covering: Installation over an existing roof covering is limited to a Finally, it is suggested to use sealing sidelaps as well as endlaps with butyl or butyls sealing tape to ensure a strong weather seal. If there are two layers there, it will weigh anywhere from 5.0 to 6.0 pounds/square foot. We use “Self-adhered” underlayment and then nail shingles over it. In installation, be sure to space the purlins no more than 24” horizontally. If your metal roof is going on top of asphalt shingles, then there is already an underlayment… Breathable underlayment is rated by perm, which is also described as water vapor transmission. Metal panels are to be screwed directly into the purlins. Furring strips must be designed to provide adequate uplift resistance. I am thinking about doing my roof myself and was wondering if you would recommend covering my entire roof in ice and water. If you opt to put the metal roof atop current roof shingles, it needs to be done in combination with a synthetic underlayment (recommended). There is a third product that is sometimes used and specified in new construction: That product is a mesh that would go on top of and over the other underlayment used. The company has chosen a local approach to the market through its U.S. representative and now has a roll forming company in Indiana supplying and selling CondenStop. Project, news and product submissions are welcomed...see information in Contact Us section. The product uses layered synthetic non-woven fleece with unique Thermoplastic Microspheres. Many people think breathable means from one side through to the other. Water damage can spread throughout your whole house, which can weaken overall structure and lead to mildew and mold, hence the purpose of roof maintenance and routine checkups. These products work best in buildings with any kind of activity that creates moisture or humidity that will eventually find its way into the attic space and the metal roof. Actually in all types of roofing you can get incidental moisture when there is a hard driving rain. He also noted that Colbond’s condensation control product is an energy saving device because it prevents heat gain in the warmer climates or times of the year. Limitations: Roof Framing: Install the metal roof panels over a minimum 16-gauge steel purlins as specified in Table 1. Choose your screw size based upon the thickness of the decking material. ~ Dave. For new construction, Florida building code does not require the use of a purlin system, and some profiles, like our TCM-LOC panel, does not require use of purlins. And for added warmth, noise reduction and protection against condensation, you can install additional insulation in the spaces between your 2” x 4”s. It’s only one way breathable and needs a ventilated envelope with circulation. “Our company got into condensation control when we were asked by a zinc manufacturer to help prevent white rust. If desired, you can also place the underlayment right over the old shingles or purlins to act as an added barrier from moisture and the elements. The spacing of your purlins depends on the expected snow and wind load. With outside air that is cooler than the building temperature you’ll have condensation and some situations may be more difficult than others. Now there is a third-generation underlayment with three-dimensional mesh attached to breathable underlayment, which eliminates the need for purlins. Benefits of Metal Roofing in Wildland Urban Interface Areas, Metal Roof Performance in Coastal High Wind Regions, Decra Shingle XD – An Impressive 50-Year Roof, Metal Roofing and the 2018 California Carr Fire – How One Home Survived, Condensation and Ice Damming on a Metal Roof. I also … “When you have a climate-controlled building there is not much use for our product unless it is a retrofit where the old roof stays and CondenStop is put under the new roof so that condensation will not form. People are looking for more effective ways to control what happens in the building envelope. CondenStop is delivered with an applied hot melt adhesive and a release foil protecting it. The Best Underlayment for Metal Roofs. This can be done in a few ways, including installing the metal roof on top of the existing asphalt shingle roof. However, it is important that you know the weight capacity of your roof and how many layers of shingles are currently on the roof. David Nemes, President of Nemco Industries, Inc., West Vancouver, BC, Canada, noted that lack of adequate air space is a typical problem. BUILD June/July 2007 and underlay used with concrete or clay tiles, where 150 mm minimum laps are required. The final product can be used in new and retrofit projects. The Enkamat product also helps control both airborne noise and impact noise such as the sound of rain on the roof. Ours is a breathable product that has a very open structure and a high absorption capacity. ”With metal roofing, the most common installation methods in terms of selection and installation of underlayment is skipping the purlins and placing the metal right on the deck. When moisture forms underneath a zinc roof it can form white rust that if it is not eliminated can eventually damage the roof. You may potentially save costs by doing spot repairs before installing the new roof in lieu of a complete tear off. Hot, dry climates or areas where temperature swings are minimal are not key markets. The fleece for the product is manufactured in the Netherlands and distributed throughout the United States from the Indiana location. Our product also works well with solar energy when a new roof metal roof is placed on top of an existing one,” he adds. A major benefit of having the CondenStop applied in the manufacturing process is that it means faster installation time in the field. Where Fortinet Ninjas hang out. Another option for installing a metal roof over shingles requires first laying a vapor barrier pound felt followed by the Grandrib 3 panels. Once you determine the structure to be safe and sound, you can begin installing the new metal roof. 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