Next, secure the drip cap to your siding using galvanized nails. Be sure that when you do this, the cap itself slopes away from the window downwards, forming an awning over the window. Localized concentrations of water can lead to discoloration, staining, and rapid deterioration of cladding materials. Required fields are marked *. 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. Turns out not all drip edge flashing perform the same. The water collected in each trough is shown as a percentage of the total amount of water applied during the test. When a stream formed, it was consistent for the entire test. For example, the depth and projection of the profile might be chosen in part to emphasize light and shadow on the elevation. 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. eight degree). Also provides alignment edge for shingle overhang. 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. There was no water collected in any of the troughs during the test of the stone sill with a small (. As water was deposited below the drip edge, it was caught by the troughs. Pry up or remove a row from top side of window. Following the tests on metal drip edges, a slightly sloped (i.e. edges of roofs, balconies, and other projecting building elements. overhang had greater measured water-shedding capability when compared to the 20-mm (0.8-in.) Your testing is appreciated because I see a lot of water damage due to false assumptions leading to improperly selected and installed flashing. Apply tape above blinking window. 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. 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. Figure 7 shows the large radius of the thick 12-gauge metal hemmed drip edge. Then again maybe rocket science is not that difficult. 45-degree kick-out or 90-degree vertical edge; overhang distance of 20 and 45 mm (0.8 and 1.8 in.) Drip Edge Extension for extending drip edge. In older buildings, surface detailing and the use of heavy stone and masonry wall assemblies have traditionally managed rainwater quite well. eight-degree) stone windowsill was tested. AMICO Window & Door Drip Edge is used to provide added protection for system edges at the top of windows and doors. Drip edge /drip ej/ (noun) "The leading edge of a flashing, sill, overhang or other linear, horizontal building element designed to shed water." ... atop parapet wall directs rain to the outside of the house in several locations showing negative effect on siding and windows. 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. The best-rated product in Drip Edge Flashing is the 10 ft. 29-Gauge Galvalume GR2 Gable Rake Flashing. While sills are a great place to put plants, they’re also a necessary part of the window, keeping out rain and making windows more energy efficient. 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. It has the main function of controlling water flow on the roof which has many implications. In every case in Figure 5, the 45-mm (1.8-in.) Horizontal distributions (i.e. 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 Drip cap. 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. 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). 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. Without elbows, water flows over the surface of a house—the wall—until it hits … 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. Both the 20-gauge 90-degree drip edges without a hem had greater than 90 per cent shedding. Five foot section. Sealant was applied to the edges of the metal flashing to prevent lateral flow of water off the side edges. —RDH Building Science Labratories. (Note: scroll to the bottom of the page for detailed specification drawings.) It is unclear why the 45-mm overhang performed more poorly in this case. FREE Shipping on orders over $25 shipped by Amazon. There are two primary functional requirements of the drip edge. Please Note: Prices, promotions, styles and availability may vary by store and online. beyond the jamb flashing. The larger 45-mm (1.8-in.) Water penetrating the roof, wall, and foundation can cause deterioration of the building’s structure, damage to property, and mould growth. expansion space all around. 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. When notching panel at bottom of window, leave 1/4-in. 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. An overview of drip edge design 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. Head flashing. overhang length. 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. By Jonathan Smegal, M.A.Sc., and Trevor Trainor, M.A.Sc. Fold-down at the end of the flashing caps it off. 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. Both vertical and horizontal distribution is necessary to avoid concentrations of rainwater. This article is appreciated. Stone sill However, there has been little research on the effectiveness of different drip edge designs. 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. Was discussing this yesterday where edge laid brick sills had no drip edge and was creating spalling and so on down the wall. 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). To push water to the outside, builder’s felt and flashing membrane direct water past the nailing hem of the first full panel below the window. Get it as soon as Mon, Feb 1. Thank you again for this thorough research and sharing… Test apparatus 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. "D" edge has extended lip that overhangs edge of roof to carry water away from fascia. 3) could be improper, missing, or failed flashing around the window, or of drip edge over the top, or of caulking. Yes, Drip Edge Flashing can be returned and have a 180-Day return period. Eliminate waste. McCoy's proudly carries Amerimax Home Products, Inc and Tamyln products in many locations. Ninety-degree drip edge analysis Exceedingly welcome research..So generously shared! Free delivery with $45 order. All the drip edges without a hemmed edge shed more water than the identical comparison drip edge with a hemmed edge. Adding a 45-degree kick-out also increased the percentage of water shed from the apparatus compared to the 90-degree vertical drip edge. Then, cut out the topmost portion of the drip edge … $13.17 $ 13. The only exception to this trend during testing was the 90-degree hemmed 12-gauge drip edge. Can Drip Edge Flashing be returned? Control the content you see on ConstructionCanada.net! 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. 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. patterns of drips from the edge along the length of the drip edge) were observed and described qualitatively. It takes a little more time to bend a nice drip cap flashing but it’s the right thing to do. Therefore, they must be designed with esthetic concerns in mind. When I started working on homes in the 1970s, installing metal drip edge was entirely the installer’s choice. Choose brown for a dark-colored roof. 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. The drip edge is the leading edge of a flashing, sill, overhang, or other linear, horizontal building. overhang distances. 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. A horizontal copper pipe with evenly spaced holes was used to supply and distribute water to the 1220-mm (48-in.) The same geometry that makes an overhang or an awning work is active in a grate structure that is 80% open. 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. A 1.2-m (4-ft) wide and 1.2-m tall ‘wall’ was constructed to accept different windowsill and flashing details. Water must be collected from surfaces above, or at a horizontal edge, and then directed outward, away from the building enclosure. 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.). Due to the somewhat unpredictable behaviour of water flow, the test repeats show some variation. PEMKO 346C40 Clear Anodized Door Drip Edge, 19/32" Flange Height, 2-1/2" Projection, 40" Length. A two-inch rear flange is provided. Control of rainwater is a primary function of the building enclosure. An overview of drip edge design. Head flashing should extend at least 1 in. Different building geometries, cladding types, and windowsill depths would also affect the amount of water that drained from the drip edge. Your email address will not be published. This article will go over why overhang is so important and how much overhang shingles should have to dry properly. Of course, you always have the right to unsubscribe from any communications you receive from us, should you change your mind in the future. Smegal’s research has included cladding deflection tests, drainage balance testing, and specialized water uptake and vapour permeance testing. standards set by the International Code Council. Constructed from heavy-duty steel for increased strength and durability. Common drip edge locations include: windowsills; window head flashing; parapet, post, or … 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. 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). While its not rocket science, the proper design is often not understood. 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. However, city requirements may vary from one area to another. Sign-up for your account with Construction Canada. To offset the increased risk of moisture-related problems, a multiple step approach is recommended. There is a small size metal rim facing outwards and away from the roof fascia. Cut how to install drip edge over window with a length slightly wider than window. T-Drip Edge Reinforced for added strength and durability, use this traditional drip edge to repel water from rooftops. Jonathan Smegal, M.A.Sc., is a senior associate with Building Science Consulting Inc. 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