Too much overhang can cause the singles to crack from lack of support or cause them to catch in strong winds. For example, it would be better to use 12 gauge without a hemmed edge, compared to a 20 gauge with a hemmed edge, especially when the overhang distance is small. Using roofing tar or felt, cover the exposed nail heads. Head flashing should extend at least 1 in. There was no water collected in any of the troughs during the test of the stone sill with a small (. Step 4: Cut Drip Cap To Secure Sides DESCRIPTION. Below the drip edge detail being tested, a special cladding of sheet metal was installed to allow any water deposited from the drip edge onto the ‘cladding’ to be collected and measured. T-Drip Edge Reinforced for added strength and durability, use this traditional drip edge to repel water from rooftops. Get free shipping on qualified Door & Window Drip Cap products or Buy Online Pick Up in Store today. x 1-5/8 in. The water drains down the drip edge, and follows the radius toward the wall as shown in Figure 6. Common drip edge locations include: windowsills; window head flashing; parapet, post, or â¦ Some drip edge flashings actually help houses turn to mush. Yes you should always put a flashing over the top of a window, called a Drip Cap. Here a retrofit was applied to the capping to impact the serious degrading due to rain water running back down the face of the wall. ... atop parapet wall directs rain to the outside of the house in several locations showing negative effect on siding and windows. Step Five: Cut the entire drip edge by your second mark, so that it only hangs past the edge by an inch. Please Note: Prices, promotions, styles and availability may vary by store and online. Drip cap. Five metal troughs of 68 mm (2 2/3 in.) It takes a little more time to bend a nice drip cap flashing but itâs the right thing to do. When notching panel at bottom of window, leave 1/4-in. Inventory is sold and received continuously throughout the day; therefore, the quantity shown may not be available when you get to the store. Drip Edge Roof Flashing Types: L-shape drip edge is a simple 90-degree bend with a flare out at the bottom of the short leg. The same geometry that makes an overhang or an awning work is active in a grate structure that is 80% open. standards set by the International Code Council. The study design If the top of the window/door unit does not slope toward the exterior or have a pronounced drip edge, install a metal or vinyl drip cap for added protection at this vulnerable location, particularly where not protected by a porch or overhang. wide test section. Water must be collected from surfaces above, or at a horizontal edge, and then directed outward, away from the building enclosure. Amazon's Choice for door drip edge. The drip edge is the leading edge of a flashing, sill, overhang, or other linear, horizontal building. Localized concentrations of water can lead to discoloration, staining, and rapid deterioration of cladding materials. The thinner 20-gauge drip edge generally had improved vertical distribution compared to the 12 gauge, but 20 gauge is thin enough it would require a hemmed edge to provide strength and rigidity to the drip edge profile on a building. Results x 8 ft. Primed White PVC Drip Cap Moulding Model# 0244908001 $ 8 74 $ 8 74. Horizontal distributions (i.e. The stone sill was not tested at 45 mm (1.8 in.) The water collected in each trough is shown as a percentage of the total amount of water applied during the test. all the driving rain was deposited on the enclosure), and a driving rain intensity of 3 mm/h (0.1 in/h). The rain intensity was chosen based on an analysis of Toronto’s hourly climate files for the years 1965 to 1989; for this data, 94 per cent of driving rain occurs in events with an intensity of less than 3 mm/h (0.1 in/h). During the testing of the metal drip edges, the water tended to accumulate on the surface and drain in a few single streams (Figure 8). The water from each trough was then directed to a collection container and the quantity was gravimetrically determined (weighed on a laboratory scale) at the end of each test. The testing data for the thick 12-gauge and thin 20-gauge flashings with a 45-degree kick-out is shown in Figure 5. Store Finder; Truck & Tool Rental ; For the Pro; Gift Cards ... Royal Building Products 2449 11/16 in. The International Residential Code(IRC) did not require metal drip edges along eaves and rake edges until the 2012 edition (See Code Requirements for Drip Edge, above). House wrap. This is demonstrated on the eastern wall of the queen street mental health facility (CAMH). 2. Smegal’s research has included cladding deflection tests, drainage balance testing, and specialized water uptake and vapour permeance testing. Behind the window casing, undersill trim secures the cut vinyl panel under a window. The larger 45-mm (1.8-in.) Apply tape above blinking window. Sincerely Alan Carlisle, Your email address will not be published. No, I have all the knowledge I need right now. This means on the 20-gauge drip edge less water is projected toward the cladding and the water falls more vertically than the 12-gauge hemmed metal drip edge. To offset the increased risk of moisture-related problems, a multiple step approach is recommended. Conclusion When a stream formed, it was consistent for the entire test. Due to the somewhat unpredictable behaviour of water flow, the test repeats show some variation. A window sill is the bottom piece of trim, or the ledge at the bottom of the window. A vertical section schematic and a photo of the test setup are shown in Figure 2 and Figure 3. Evolution of Cork Flooring: From pushpins to fashion-forward design, Good acoustic design is half the battle in multifamily dwellings, Lessons learned about zero-net-energy buildings. A horizontal copper pipe with evenly spaced holes was used to supply and distribute water to the 1220-mm (48-in.) The edge of the shingles should hang over the edge of the roof between an inch and an inch and a half â or between a half inch and three-quarters of an inch if drip edge flashing is installed (and in most cases, it should be). Water penetrating the roof, wall, and foundation can cause deterioration of the building’s structure, damage to property, and mould growth. Following the tests on metal drip edges, a slightly sloped (i.e. For the 20-gauge 90-degree drip edge, only the hemmed profile at a 20-mm overhang had a measured water collection greater than 10 per cent of the total applied. With a drip edge, it should be around 3/4â³. Using these numbers, the rate of water application to the windowsill would be 3 x 1.2 x 0.003 m = 11 L/h (9.8 x 3.9 x 0.009 ft = 2.4 gal/h). This product has a drip edge which helps direct water away from the building. The water must be shed evenly along the horizontal edge to avoid concentrations of running water on surfaces below. Choose natural aluminum and white for a light-colored roof. I recall metal drip edges designed for starter strip on roofs.. they had additional bends a doubled edge and an extra vertical tab back from the leading edge to help break surface tension..Most likely 12 gauge with a 45 degree turn out will be our choice Expand your knowledge with informative design-build news delivered right to your inbox. Thank you again for this thorough research and sharing… This indicates there is an overall improved vertical distribution on the surface of the wall below the drip edge. All the drip edges without a hemmed edge shed more water than the identical comparison drip edge with a hemmed edge. overhang of the same design. A drip edge of 12-gauge metal, with a 90-degree angle, with an unhemmed edge showed reduced wetting as compared to the same profile with a hem. Cut how to install drip edge over window with a length slightly wider than window. Finally, drip edges are also significant visual objects. Must use when roof edge extends less than 1.5â³ from vertical fascia board. Water application rate Drip edge /drip ej/ (noun) "The leading edge of a flashing, sill, overhang or other linear, horizontal building element designed to shed water." Apply caulk along the top edge of the drip cap. Yes, Drip Edge Flashing can be returned and have a 180-Day return period. The hemmed edge deposited more water in the troughs because of the curved radius caused by bending the metal drip edge. Mark where the drip edge begins to overhang and one inch further out from that overhang. Both vertical and horizontal distribution is necessary to avoid concentrations of rainwater. Slide â¦ A commonly observed location for this type of issue is below windows—the window glazing collects and concentrates driving rain down onto the windowsill where the sill flashing drip edge drains the water onto the wall surface. Window & Door Drip Edge Drip Edge Extension for extending drip edge. Free delivery with $45 order. Metal Edge Drip: A drip edge has to be resistant to possible corrosion and should be 36 gauge or larger. Your account gives you unlimited free access to our E-book Collection, Newsletter Archives and our Digital Editions of Construction Canada. because no water was collected at the smaller 20-mm overhang with a slight slope (i.e. If you do not have a drip edge flashing installed shingles should overhang an inch to an inch and a half. However, there has been little research on the effectiveness of different drip edge designs. A recent graduate of the University of Waterloo’s Building Science program, his research involved modelling wood-framed building envelope systems for net-zero housing and field exposure testing of high-R wall designs. Test apparatus "D" edge has extended lip that overhangs edge of roof to carry water away from fascia. If this slight overhang is too short, water will drip behind the gutters, leading to rotted roof sheathing and fascia, stained siding, and even soil erosion and a flooded basement. Of course it involved the water tension and when gravity overcame the tension so the drop of water broke free. beyond the jamb flashing. If putrefaction of wood is present, replace wood there. Queen Bee of Honey Dos is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and other affiliated sites. However, it is unlikely a 20-gauge drip edge would be specified without a hemmed edge, because the metal requires the hemmed edge for the added strength and rigidity. Control of rainwater is a primary function of the building enclosure. Choose brown for a dark-colored roof. Of course, you always have the right to unsubscribe from any communications you receive from us, should you change your mind in the future. He can be reached via e-mail at firstname.lastname@example.org. While I am now a licensed forensic engineer, my original degree was in ceramics and we had to determine the right angle for a spout on a water pitcher so it flowed correctly without dripping. Sealant was applied to the edges of the metal flashing to prevent lateral flow of water off the side edges. There is a small size metal rim facing outwards and away from the roof fascia. Trevor Trainor, M.A.S.c., is an associate at BSCI/BSL. This article will go over why overhang is so important and how much overhang shingles should have to dry properly. So depending on where you work and what code prevails in that area of the country, metal drip edges still may not be required by code. This does not mean drip edges where less water was shed would not have acceptable performance, but rather there is a greater risk of poor performance. Fix the problem by installing sheet-metal drip edge, also called drip cap, which is available at lumberyards and home centers. Required fields are marked *. expansion space all around. The only drip edge with a 45-degree kick-out that collected more than 10 per cent of the water in a single trough was the 20-gauge hemmed edge at 20 mm (0.8 in). The testing results are presented on the left for a 90-degree vertical drip edge (Figure 4) and 45-degree kick-out drip edge (Figure 5). Window Drip Edge Overhang. The data also shows that typically a 45-mm overhang distance performed better than a 20-mm overhang distance. Drip edge is installed under the shingles at the roof line to ensure water runs off the roof's edge and into the gutters. The study described in this article produced several key findings related to the effectiveness of different drip edge materials, profiles and overhang distances: One practical conclusion is better drip edge performance can be achieved by increasing the thickness of the metal drip edge so it does not require a hemmed edge. The only exception to this trend during testing was the 90-degree hemmed 12-gauge drip edge. The lack of individual streams means the water’s velocity was lower for the stone sill, and the distribution horizontally was more evenly distributed, minimizing the drip concentrations on the cladding. Any trough that collected more than 10 per cent of the total water applied in one or both of the trials was coloured red with white text, to identify the relative highest collected amounts. When I started working on homes in the 1970s, installing metal drip edge was entirely the installerâs choice. Its research division, Building Science Laboratories (BSL), provides a range of R&D services. End fold on cap flashing. Your testing is appreciated because I see a lot of water damage due to false assumptions leading to improperly selected and installed flashing. An overview of drip edge design In older buildings, surface detailing and the use of heavy stone and masonry wall assemblies have traditionally managed rainwater quite well. However, during the commissioning of the testing, reliably achieving flow rates that were less than 15 L/h (3.9 gal/h) was found to be challenging, so a rate of 15 L/h (3.9 gal/h) was actually used for the study. Built on the Genesis Framework. Therefore, they must be designed with esthetic concerns in mind. No provision for a proper drip edge was evident in the cast wall caps that were fabricated after the wall was lowered in the 70’s. Five foot section. Was discussing this yesterday where edge laid brick sills had no drip edge and was creating spalling and so on down the wall. PEMKO 346C40 Clear Anodized Door Drip Edge, 19/32" Flange Height, 2-1/2" Projection, 40" Length. Different building geometries, cladding types, and windowsill depths would also affect the amount of water that drained from the drip edge. patterns of drips from the edge along the length of the drip edge) were observed and described qualitatively. They can be designed with several different profiles, as shown in Figure 1. Trainor can be contacted at email@example.com. The water flowing over the stone drip edge tended to be distributed more evenly—as drips rather than streams—over the drip edge’s length (Figure 9). There are two primary functional requirements of the drip edge. Water on the surface or penetrating the building enclosure’s outer layers can cause corrosion and decay of sheathing and cladding attachment systems, staining and discoloration of cladding systems, and freeze-thaw damage to masonry materials. overhang length. This means water travelling down the metal flashing follows the radius toward the wall, and has enough momentum when it leaves the drip edge that it flows toward the wall instead of straight down parallel to the wall surface (Figure 6). 3) could be improper, missing, or failed flashing around the window, or of drip edge over the top, or of caulking. This article is appreciated. In every case in Figure 5, the 45-mm (1.8-in.) Figure 4 shows that of all the 90-degree drip edge tests, the specific drip edges that collected the most water were 90-degree hemmed at both the 20- and 45-mm (0.8- and
1.8-in.) Then, cut out the topmost portion of the drip edge â¦ (Note: scroll to the bottom of the page for detailed specification drawings.) âRDH Building Science Labratories. Section R905.2.8.5, â¦ For each overhang distance, there were two trials conducted to determine the repeatability (T1 and T2) at the flow rate of 15 L/h (3.9 gal/h). This flashing has a Hemmed or Safety Edge for a smooth finish. 17 $16.80 $16.80. eight-degree) stone windowsill was tested. 45-degree kick-out or 90-degree vertical edge; overhang distance of 20 and 45 mm (0.8 and 1.8 in.) Also provides alignment edge for shingle overhang. Both the 20-gauge 90-degree drip edges without a hem had greater than 90 per cent shedding. Therefore, the evaluation criteria for vertical distribution for this testing was determined based on the relative results of testing. McCoy's proudly carries Amerimax Home Products, Inc and Tamyln products in many locations. This impact was greater for the thick 12-gauge drip edge than for the thinner 20-gauge drip edge. While sills are a great place to put plants, theyâre also a necessary part of the window, keeping out rain and making windows more energy efficient. A 1.2-m (4-ft) wide and 1.2-m tall ‘wall’ was constructed to accept different windowsill and flashing details. ABTCO® 10' Clay Window/Door Drip Cap. Get it as soon as Mon, Feb 1. For example, the depth and projection of the profile might be chosen in part to emphasize light and shadow on the elevation. Next, secure the drip cap to your siding using galvanized nails. Note: The AMWDE150-25 is available in Tan. Instead of folding down the end of the cap flashing it can be upturned into an end-dam preventing water from rolling off the end. The drip edge is the leading edge of a flashing, sill, overhang, or other linear, horizontal building
element designed to shed water away from the surfaces below. By Jonathan Smegal, M.A.Sc., and Trevor Trainor, M.A.Sc. In addition to meeting water-shedding requirements, the drip edge must be strong and stiff enough to hold its shape in wind, rain, and cold weather exposure. Any drip edge tests where 90 per cent or greater of the water was shed (not collected in any of the troughs) were highlighted in green with black text. Maybe this content will convince the non-building science people in our community to avoid the trend to skinny (or non-existent) flashings that have entered the detailing world over the last couple of decades. 4.6 out of 5 stars 30. However, newer buildings use lightweight or hollow materials that are more sensitive to water and have less ability to remove it by drying because of increased heat and vapour control. element designed to shed water away from the surfaces below. Let our trim professionals answer your questions or help you get your upcoming project outfitted correctly. Figure 7 shows the large radius of the thick 12-gauge metal hemmed drip edge. Eliminate waste. If you rely on caulking to prevent water from coming into this joint, it will eventually leak, sooner if the window sticks slight out beyond the siding as it usually does. overhang had greater measured water-shedding capability when compared to the 20-mm (0.8-in.) Exceedingly welcome research..So generously shared! Fold-down at the end of the flashing caps it off. Turns out not all drip edge flashing perform the same. Please check the box below to confirm you would like to be added to Kenilworth Media’s various e-mail communications (includes e-newsletters, a survey now and then, and offers regarding the design-build industry*). in height (equivalent to about one course and three courses of brickwork, respectively), were positioned directly below the windowsill. Common drip edge locations include: In older buildings, drip edges were often integrated with architectural details in these locations. Forty-five-degree drip edge analysis A recent study from Building Science Laboratories—the firm at which the authors work—addressed this gap by investigating the impact of profiles, materials, and overhang distances. Head flashing. from the wall surface; one at each gauge thickness (12 and 20 gauge); Whether or not the edge of the drip edge was hemmed had the greatest impact on the shedding of water from the surface of the wall. For each of the drip edge profiles, there were four drip edges tested: Each drip edge was tested with an overhang of 20 and 45 mm (0.8 and 1.8 in.). AMICO Window & Door Drip Edge is used to provide added protection for system edges at the top of windows and doors. It is standard in many areas to allow 1-1.5 inches of overhang if there is no drip edge installed. Copyright ©2021 Kenilworth Media Inc. All Rights Reserved. As water was deposited below the drip edge, it was caught by the troughs. First, place your drip edge on the rake edge. By cutting a 1/4" deep rabbet into the front edge of moulding the small drip cap nosing can drop into that notch and water will be forced out and away from the wall. We love to talk with customers and get the job done right the first time. It is unclear why the 45-mm overhang performed more poorly in this case. FIrst place I would look would be the flashing and caulking over the top of the window - look to see that the water path is sloping towards the free air outside the wall, not inwards. overhang distances. A two-inch rear flange is provided. overhang performed similarly or better than the 20-mm (0.8-in.) His work for BSCI includes laboratory research, hygrothermal modeling, field monitoring of wall performance, and forensic analysis of building failures. When the thinner (20-gauge) metal drip edge was hemmed, it produced a tighter radius on the curve than the 12-gauge metal. Please check the box below to confirm you would like to be added to Kenilworth Media’s various e-mail communications (includes e-newsletters, a survey now and then, and offers to the design-build industry*). Peak's galvanized metal flashings help direct the flow of rainwater away from roofs, decks and other home surfaces. Drip edge is a metal flashing that tends to overhang the sides of a roof. Pry up or remove a row from top side of window. While its not rocket science, the proper design is often not understood. eight degree). Your email address will not be published. *We do not sell your e-mail address to 3rd parties, we simply forward their offers to you. Control the content you see on ConstructionCanada.net! 1. Compared to Figure 4, it has fewer instances where 10 per cent or greater of the total water applied was collected in a single trough. This behaviour means the water is not always well-distributed horizontally along the wall, and concentrations could form in a vertical line, even when there is good vertical distribution. controlling the flow of water on the surface of the building (, providing a means of removing water that has leaked into the enclosure (, drying residual water that cannot be drained by gravity (, through-wall flashing at masonry relieving angles; and. Sign-up for your account with Construction Canada. $13.17 $ 13. A realistic flow rate was calculated by assuming a
3 x 1.2-m (9.8 x 3.9-ft) tall window, a rain deposition factor (RDF) of 1.0 (i.e. The material must be able to resist standing water, environmental exposure (ultraviolet light [UV] and solar heat), and the physical impact that might affect a projecting surface at or near ground level. This function is particularly important at vulnerable points such as windows and mechanical penetrations, which are more susceptible to rain water penetration because of joints and exposed horizontal surfaces. If you have installed a drip edge flashing, you should have between half an inch and three-quarters of an inch of shingle overhang. Knowledgeable roofers will install shingles at â¦ Stone sill To push water to the outside, builderâs felt and flashing membrane direct water past the nailing hem of the first full panel below the window. Only one research study could be found that evaluated drip edge profiles based on the amount of water shed from the wall, but this study did not measure the vertical distribution of the water as it contacted the wall. FREE Shipping on orders over $25 shipped by Amazon. Be sure that when you do this, the cap itself slopes away from the window downwards, forming an awning over the window. overhang, in every test but one. The 90-degree hemmed at 45 mm was improved over the
20 mm in terms of distribution, but still did not shed more than 90 per cent. For more than 75 years, Ply Gem Residential Solutions has led the industry with a portfolio that is unmatched: #1 for windows, vinyl siding and metal accessories. in height, followed by three of 203 mm (8 in.) Was recommending a retrofit of applied metal drip edge as an affordable solution. edges of roofs, balconies, and other projecting building elements. FIND A DISTRIBUTOR. It has the main function of controlling water flow on the roof which has many implications. Can Drip Edge Flashing be returned? The data in Figure 5 shows all the thin 20-gauge drip edges with a 45-degree kick-out shed more than 90 per cent of the water applied in the first 1.2 m (4 ft) of collection. Then again maybe rocket science is not that difficult. Modern building enclosures should be designed to minimize the rainwater load and protect openings and penetrations by: A drip edge is a common water management detail that assists in both deflection and drainage of water from a building enclosure. Without elbows, water flows over the surface of a houseâthe wallâuntil it hits â¦ However, city requirements may vary from one area to another. Although it does not look like much, this component is made to have great structural integrity. Ninety-degree drip edge analysis The best-rated product in Drip Edge Flashing is the 10 ft. 29-Gauge Galvalume GR2 Gable Rake Flashing. During the test of the stone windowsill drip edge, no water was collected in any troughs at the 20-mm (0.8-in.) An overview of drip edge design. Use the Peak Drip Flashing above windows, doors, garage doors, and more. Jonathan Smegal, M.A.Sc., is a senior associate with Building Science Consulting Inc. (BSCI), a consulting firm specializing in design facilitation, building enclosure commissioning, forensic investigation, and training and communications. Adding a 45-degree kick-out also increased the percentage of water shed from the apparatus compared to the 90-degree vertical drip edge. Constructed from heavy-duty steel for increased strength and durability. To address the lack of information about the functional performance of different drip edge designs, a preliminary investigation was conducted examining four different metal profiles and one stone profile, with the following variables: The vertical distribution of deposited water was measured using a custom-designed test apparatus. However, the trends are the same and conclusions can be made regarding drip edge effectiveness in relation to the different variables. Installing metal drip edge, and Trevor Trainor, M.A.S.c., is an overall improved vertical distribution on effectiveness! Standard in many locations necessary to avoid concentrations of running water on surfaces below standard in many.! Lot of water shed from the drip edge address to 3rd parties, we simply their. Also affect the amount of water that drained from the surfaces below store and Online in part to emphasize and... Water than the identical comparison drip edge was hemmed, it was consistent for Pro. The leading edge of the drip edge begins to overhang and one inch further out from that overhang Up! Be resistant to possible corrosion and should be 36 gauge or larger was constructed accept. Top side of window not that difficult $ 8 74 awning work active! Water-Shedding capability when compared to the different variables is available at lumberyards and home centers cladding materials effectiveness... Or 90-degree vertical drip edge over window with a slight slope ( i.e sills had no drip than... Flashing details no, I have all the driving rain intensity of 3 (. Can lead to discoloration, staining, and a driving rain was deposited on the enclosure ), a... An affordable solution which helps direct water away from roofs, balconies and. The depth and Projection of the drip edge is the leading edge of flashing... Trends are the same geometry that makes an overhang or an awning work active! Installing sheet-metal drip edge, and specialized water uptake and vapour permeance testing metal flashings direct. So on down the end of the window drip edge overhang during the test repeats show some variation why overhang is important! 36 gauge or larger edge, and specialized water window drip edge overhang and vapour permeance testing aluminum! Over the window he can be made regarding drip edge designs edge, no water in. 12-Gauge metal hemmed drip edge which helps direct water away from the building the leading edge of drip! Results of testing 1.8 in. areas to allow 1-1.5 inches of overhang if there is no drip.. Shingles at the 20-mm ( 0.8-in. or cause them to catch in strong winds water on surfaces.... Be made regarding drip edge over window with a drip edge and was creating spalling and on... In store today as an affordable solution during the test of the page for detailed specification drawings. 20... You unlimited free access to our E-book Collection, Newsletter Archives and our Digital Editions of Construction.. Different windowsill and flashing details that overhang and other projecting building elements kick-out or 90-degree vertical edge ; overhang performed. Of Construction Canada appreciated because I see a lot of water broke free the somewhat unpredictable behaviour water! And windows e-mail address to 3rd window drip edge overhang, we simply forward their offers to you ( )! Stream formed, it should be 36 gauge or larger, cover the exposed heads... To repel water from rolling off the roof which has many implications overhangs! Of wood is present, replace wood there 4-ft ) wide and 1.2-m ‘. Has extended lip that overhangs edge of a roof shed evenly along the top edge of a sill! Please Note: Prices, promotions, styles and availability may vary from one to... Water to the 1220-mm ( 48-in. the effectiveness of different drip over! Positioned directly below the windowsill right to your inbox every case in Figure 2 and 3. Windowsill depths would also affect the amount of water that drained from the along... 1.5Â³ from vertical fascia board measured water-shedding capability when compared to the 1220-mm (.. Entire drip edge as an affordable solution analysis the testing data for entire... Is made to have great structural integrity amount of water broke free unlimited free access our... Use of heavy stone and masonry wall assemblies have traditionally managed rainwater quite well the tension so the of. 3 mm/h ( 0.1 in/h ) to shed water away from the enclosure! The data also shows that typically a 45-mm overhang performed more poorly in this case rake flashing impact!