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Stramit® Rainwater Products New South WalesStramit® Gutters Stramit® Fascia Stramit® Fascia Batten Stramit® Downpipes Other Stramit® Rainwater & Flashing Products Performance Stramit® Rainwater Products have been designed and/or tested to all appropriate loadings and design action effects. These include wind, atmospheric corrosion, rainwater flow, rainwater mass, foot traffic loads, dead loads and ladder loads.The performance information for each product indicates those action effects accounted for in each case. Rainfall Intensity Values of rainfall intensity in the table and maps are for 20 year ARI, 5 minute durations and have been derived from AS3500 part 3.2 ‘Stormwater drainage – Acceptable solutions’. It should however be emphasised that the extent and longevity of records in Australia are limited and any such data therefore carries with it a degree of uncertainty.The 20 year ARI values should only be used for external eave gutters. For internal/box gutters use 100 year ARI values such as those in the Stramit Design Guide – ‘Roof Slope’.
The map is only intended to indicate the variability of rainfall intensity within the region shown. Specific data for any location can be obtained from the Commonwealth Bureau of Meteorology in Melbourne. Snow It is common practice not to use gutters in snow prone areas but to take care of roof run-off at ground level. Information on designing in snow areas can be found in Standards Australia Handbook HB 106 “Guidelines for the design of structures in snow areas”. In snow prone areas Stramit® Fascia may only be used with a tilt batten designed to take the additional roof loading. Hail Stramit® Steel Gutters are able to resist impact from significantly sized hail without damage. However, in hail prone areas consideration should be given to ensuring that gutter fronts are well below roof level. This should avoid the damming effect of hail which, if it builds up onto the roof, can lead to overloading and failure of the gutter. Leaves Leaves in gutters can be a problem. They come in many shapes and sizes and roof debris may also include branches, twigs and both organic and inorganic particles. Many systems have been and are used to try to solve this problem. The optimum solution will vary with each situation and may be influenced by a number of factors that include the nature and proximity of vegetation, the level of maintenance and the primary motivation (eg water collection, maintenance reduction, gutter system durability, bushfire hazard reduction etc) One method is to use adequately sized gutters set well below the roof edge with a good fall and large downpipes with well angled offsets to avoid corner blockages, clear frequently and remove overhanging vegetation. An often-used method is an additional mesh guard or perforated gutter covering. Those of a very fine mesh will keep most debris from the gutters but can be prone to dirt and algal build up leading to mesh blockage. This does keep leaves from the gutter and downpipe, but ultimately it may not allow water to pass into the gutter. Any water trapped within the gutter may not dry out which could compromise durability. Larger mesh guards stop large leaves and branches from entering the gutter but it may be possible for twigs and branches to catch in the mesh ultimately creating a dam causing water to flow back into the building eaves. It is also important, if a cover or leaf guard is used, that it is material-compatible with the gutter and that both the gutter and the guard are cleared regularly. Stramit® Gutters
  Spans Stramit® Gutters require the correct proprietary Stramit® brackets (or snap clip/stiffener bracket combination) for support at spacing no greater than those shown in the following table.
Thermal Expansion Gutter runs in excess of 20m require the provision of an expansion joint. Fall Stramit recommends that an absolute minimum fall of 1 in 500 be used for all gutters, this being a design requirement for the gutter and downpipe selection table. Good fall reduces the risk of leaf and debris deposition that could otherwise effect durability. Gutter Capacity In theory any size of gutter can be used to drain any roof catchment.What controls design is the number of downpipes needed to perform within the capacity of each gutter. In practice the larger the gutter the less the number of downpipes required, as indicated in the table [below]. Normally catchment calculations must take into account the increased area due to roof slope. The required downpipe table incorporated into this manual takes account of roof slopes up to 23°. Therefore the roof area for use with this table requires only the simple calculation of plan area.  The selection of the number of downpipes is carried out in accordance with AS3500.3.2 (Stormwater drainage – acceptable solutions). However, the larger the gutter the larger the downpipe required. The minimum size of downpipe associated with each Stramit® Gutter is given in the Stramit® Downpipes section that follows. Stramit® Fascia Spans
Pressures The wind resistance of Stramit® Fascia has then been determined at these spans by testing in accordance with AS4040.2 – and for each of the spans is suitable for use in areas of up to: 0.92 kPa SERVICEABILITY LIMIT-STATE, 2.25 kPa STRENGTH LIMIT-STATE. These pressures are equivalent to: N3 (Region A – rural, Region B – exposed suburban). Stramit® Fascia Batten The Stramit® Fascia Batten protects pre-installed fascia against foot traffic damage by creating a guard behind it. The strong, low profile batten is installed at the same time as the metal fascia, on the rafter ends, using standard fasteners. By providing a trafficable barrier, the Stramit® Fascia Batten reduces the risk of roofers accidentally treading on the pre-installed fascia during roofing installation. This saves on the cost of replacing damaged fascia and brackets, as well as saving time in call-backs to reinstall the fascia. The Stramit® Fascia Batten also increases safety by aiding slip prevention and reducing the risk of potential falls. On steel roofing installations, the batten acts as a slip guard, providing the last line of secure footing.  Installation and fixing Installation of the Stramit® Fascia Batten is simple and straightforward. Using No.7 – 16x25mm bugle head needle point screws for timber or No.10x16mm hex head self-drilling and threading screws for steel, place behind fascia and stagger fasteners to roof trusses or rafters as shown in the diagrams. Two fasteners are to be used at the start and end of each batten length and are to be lip fixed only. The batten can be used at a maximum span of 600mm. For the alternative fastener location at internal supports use No.7 – 16x40mm bugle head needle point screws for timber and No.12x45mm hex head self-drilling and threading screws for steel.    Please note that the use of nails for fixing is not adequate. Note: Other Stramit® battens of larger dimensions may also be used to fulfill the same function. The same fixing screws and arrangement is required. For example Stramit® Roof Batten (40mm high) may be used in the dual role of fascia batten and tilt batten for roof tiles. Stramit® Downpipes
Sizing of minimum downpipe size relates only to the cross-sectional area of the chosen gutter. The table below gives the minimum round and rectangular downpipe size for each Stramit® Gutter.
Other Stramit® Rainwater & Flashing Products Stramit® Custom Flashings Stramit® Custom Flashings are available in an almost infinite variety of shapes and sizes. Preferred girth widths are 150, 250, 300 and 400mm and lengths of up to 8m are possible. The details of all Stramit® Custom Flashings must be provided in hard copy (e.g. fax). Contact the nearest Stramit branch for more details or refer to the Stramit Price & Service Guide for the area. Stramit® Standard Flashings All of the following products require nominally continuous support.      
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