GUTTER AND DOWNSPOUT SYSTEMS
ESSENTIAL KNOWLEDGE
The purpose of gutter and downspout systems is to collect rainwater from the roof and direct it away from the building foundation by means of downspout extensions, splash blocks, or underground drain lines. An improperly functioning gutter and downspout system can contribute to water and ice backing up against fascias and under roof shingles, can damage soffits, and can discolor or deteriorate siding materials. Faulty gutters and downspouts can also lead to soil erosion adjacent to buildings and serious water and foundation displacement problems in basements and crawl spaces. Unfortunately, gutter systems take more abuse from extreme weather conditions, particularly ice and snow, than any other component of the building envelope. They are also subject to damage from ladders and being stepped on, as well as from falling tree limbs and debris.
Gutters should be sloped a minimum of 1 inch for every 40 feet of run. Standing water may indicate a sagging or incorrectly pitched gutter. Gutters are often sized according to the roof area they drain. Five-inch-wide OGee-style gutters are the residential industry’s standard. Six-inch-wide OGee-style gutters are used for larger roofs. Half-round gutters are typically sized 1 inch wider than OGee-style to provide the equivalent capacity. Therefore, 6-inch half-round gutters are equivalent to 5-inch OGee-style.
Wider gutters may be required for certain hard surface roofing materials, such as slate and tile, or used on steeply pitched roofs, to prevent water from shooting over the gutter. Gutters should be positioned tight against roofing materials and the fascia. In heavy snow areas, snow guards should be used to prevent gutter tear-off. Vertical downspouts are used to capture and distribute rain water to storm drainage systems, or by means splash blocks, to areas away from the building’s foundation walls to prevent the build up of water in the soil and possible resulting structural or basement moisture problems. Downspouts are typically rectangular and of the same material as the gutter to prevent destructive galvanic actions. Connections between gutters and downspouts and downspouts and storm drains require continuing maintenance to assure the drain is free of leaves and debris and the connection has not become loose. Other maintenance points include the connections of downspouts to the building. Downspout diameters are sized according to the roof area they drain.
During the 1960s, roll-formed metal gutter technology was introduced that allowed metal gutters to be made lighter and less expensively. Initially available primarily in galvanized steel, roll-formed gutters are now available in copper, aluminum, galvanized, and painted steel. Gutter profiles include half-round and square, but the OGee-style (Figs. 1,2,3) predominates because it is visually compatible with recently-built housing and adds interest to simple fascia details. Recent developments in truck-mounted roll-forming equipment have allowed gutter installers to form continuous, seamless metal gutters to fit site-measured field dimensions and individual roof profiles.
TECHNIQUES, MATERIALS, TOOLS
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EXISTING GUTTER SYSTEMS.
Other than keeping gutters clean of leaves, pine needles, and debris, gutter maintenance usually involves keeping gutter and downspout screens in place, refastening downspouts, and maintaining splash blocks or connections to underground drains. Gutters deteriorate over time —At some time, usually when new roofing is required, the gutters may have weathered to the point where they are not functioning, are unsightly, or have significantly deteriorated. The choice of a replacement will be dictated by the appearance, value, physical characteristics, and age of the existing house.
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INSTALL NEW OGEE-STYLE ALUMINUM GUTTER SYSTEMS.
Aluminum gutters and downspouts are by far the most popular gutter systems. Available in a variety of styles, including Ogee-style, half-round, and a K-style modified to replace a fascia board. Coatings include baked enamel, polyester, and acrylic. Gutter thicknesses run from a lightweight 0.019 to a heavier 0.032 inch, the most typical thickness is 0.027 inch. Thicknesses below 0.027 inch are sometimes used on low-end housing and are available through price-sensitive home centers for the do-it-yourself markets. The benefit of seamless systems is the lack of joints (which are points of potential leaks if not maintained). Concealed hangers are becoming more popular because they are invisible and allow the gutter to expand and contract. Expansion and contraction at bracket support types that surround the gutter can lead to discoloration and wear at those points. Spike and ferrule fittings are sometimes unsightly due to sloppy installation, and can pull out of the fascia from the significant movement of aluminum resulting from temperature swings. (Figs. 4,5)
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INSTALL NEW STEEL GUTTERS AND DOWNSPOUTS.
Steel gutters and downspouts are available in a variety of styles, including OGee-style, square (box gutters), and half-round. Available materials include electroplated and hot-dipped galvanized and Galvalume® (approximately 55 percent aluminum, 45 percent zinc by weight). Finishes also include plain galvanized, baked enamel, modified siliconized acrylic and polyester, and fluoropolymer coatings such as Kynar. Gauges run from a lightweight 28 ga. to heavier 24 ga., with 26 ga. being the most typical. ADVANTAGES: Some newer coating systems (Kynar 500) allow limited guarantees up to 50 years. Steel is popular in Northern states with snow and ice conditions.
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INSTALL NEW OGEE-STYLE COPPER GUTTERS.
Copper has been a traditional gutter material for institutional buildings and large houses and continues to be popular for high-end custom housing. Typically specified in 16 or 20 ounces, OGee-type or in half-round styles up to 8 inches wide, copper is available in “stick” as well as seamless systems. Copper has also been used as sheet flashing in “boxed” or built-in gutters (Fig. 6).
Typically allowed to weather naturally, copper develops a blue-green coloration resulting from the formation of a protective copper oxide patina. ADVANTAGES: Considered a quality, premium product. An appropriate material for historic preservation projects. Copper patina blends well with many roofing products. Low maintenance, does not require paint. Will not rust and is well suited for maritime environments.
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INSTALL NEW HALF-ROUND COPPER & ALUMINUM GUTTERS.
Half-round gutters were the traditional gutter style on homes built before 1950 and remain a popular choice on historic renovation projects, traditional renovations, and new upscale custom housing. The simple lines of half-round gutters compliment heavily textured materials such as slate, shakes, and tiles. Where crown moldings exist in lieu of fascias, half-round gutters are hung from the roof. Where fascia exist, fascia brackets are used to attach gutters. A full line of accessories, decorative components, and screens is also available. ADVANTAGES: Appropriate for both historic rehabilitation and new construction, both contemporary and traditional. Attractive and durable. However, they have a higher initial material cost than some other gutter products (Fig 7).
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REPLACE/PROVIDE GUTTER SCREENS/GUARDS.
A variety of products are available to retard the build-up of leaves, twigs, dirt, and asphalt roofing granules in gutters. Historically these have been galvanized or aluminum or plastic screening material, but recently a host of “gutter type guard” products has emerged. These products range from slotted or perforated vinyl or metal extrusion to nylon mat filters. Additionally, some manufacturers and distributors of rollforming equipment and metal coils have produced gutters that include protective hoods.
IMPORTANT – PLEASE READ THE FOLLOWING:
There is nothing that anybody can sell you that will keep you from having to maintain a gutter system. NOTHING!!! If the product keeps most of the debris out of the gutter itself, then the product will have to be cleaned and it will say that in the warranty.
Also, you can spend a lot of money on gutter protection, but you will still have to clean the debris off of your roof or risk damage and back-up on your shingles. The only thing that will ever prevent you from cleaning leaves out of your gutter system is a CHAIN SAW. Since no one wants to give up their beautiful trees, then you should prepare for future cleaning and maintenance of your gutter system.
Source:
Roofs
Volume 3 of The REHAB Guide
HUD/PATH
