FLASHING GUIDE FOR ARCHITECTS AND DETAILING PROFESSIONALS FLASHING GUIDE

Transcription

1 FLASHING GUIDE FOR ARCHITECTS AND DETAILING PROFESSIONALS 1 FLASHING GUIDE

2 FLASHING GUIDE 2 Table of Contents 1. Introduction and Scope Design Preliminaries Product selection The purpose of flashing Materials and finishes Compatibility Support spacings Maximum lengths of roofing Low roof pitches Wind forces on roofs Codes and performance tests Specifications - roofing profiles Specifications - walling profiles Roof flashings Design Roof flashings Flashing laps Apron flashing Longitudinal flashings Transverse flashings Using notching tools Flashing at change of pitch Capped bent roofs Gutter apron Types of penetration flashing design Flashing large roof penetrations Flashing small roof penetrations Expansion Standard roof flashings Non standard roof flashings, cappings Box gutters Barge gutters and capping Typical wall flashings Cladding orientation Walling profile running horizontally Types of flashings Optional wall trims Mid-wall connections Internal wall connections External corner connections Flashing for horizontal cladding Flashing for horizontal corrugate cladding Flashings for vertical cladding Toe-Mould Type Flashing Window flashing types Window flashings for metal cladding Flush window flashings Recessed window flashings Butt window flashings Copyright Copyright in this information including any designs, text, data, graphics and images belong to BlueScope Steel Ltd, trading as Lysaght except as noted. Thanks are given to the New Zealand Metal Roofing Manufacturers Inc. For permission to reproduce text, graphics and drawings from their copyright publication - NZ METAL ROOF AND WALL CLADDING CODE OF PRACTICE (Version 2.2: 2012). All rights reserved. Such material is annotated in footnotes as such by use of this logo. Any use of this publication including reproduction, modification, distribution or re-publication, in whole or in part*, in any form or medium, without written permission of Lysaght is prohibited. Copyright BlueScope Steel Limited April 7, 2014 Produced at Lysaght Research & Technology * Except for material taken from NZ METAL ROOF AND wall cladding code of practice (Version 3: 2012) where the permission of the New Zealand Metal Roofing Manufacturers Inc. must be sought.

3 1. Introduction and Scope How to design and detail steel clad roofs and walls Clear, concise installation tips and methods for architects and draftsmen Using flashings to create an architectural feature Industry best practice explained Correct detailing of LYSAGHT roof and wall flashing has more than cosmetic importance - it is essential in ensuring the wet weather performance of the cladding. Correct flashing and detailing will improve the overall appearance of the finished job. The advice given in this manual is consistent with the requirements of the Building Code of Australia and is aimed at ensuring that correct practice is specified into building construction. In many instances, alternative methods are examined to provide a clear understanding of the implications arising from these alternatives. And finally, the examples shown are typical of the work to be carried out and may not apply to specific situations or specific LYSAGHT cladding products. In all cases, a qualified tradesman should be engaged to ensure the advice given here is applicable to your intended use. We hope that the information supplied provides clear, concise direction in the correct design and detailing of roof and wall flashing for architects and draftsmen. The manual is set out in two parts, design and flashing. For overall roof and wall design, refer to the LYSAGHT Roofing & Walling Installation Manual. If these products are to be used in cyclonic areas as defined in AS :2011, you must also refer to the Lysaght Cyclonic Area Design Manual. Both these publications are available at: 3 FLASHING GUIDE

4 2 Design preliminaries 2.1 Product selection When you incorporate steel cladding into your building Lysaght offers a wide range of profiles from which to choose. Whilst roofing and walling obviously have to keep out the weather, they also have significant effects on the looks, cost and durability of a building. If you are unsure about any product feature, visit call our information line or seek advice from the relevant specialists. Lysaght has been supplying the Australian building industry with premium products for over 0 years, and our technical literature provides the engineering data to design buildings using our products. In particular, architects and builders should consult chapters 2 to 6 of the LYSAGHT Roofing & Walling Installation Manual. We urge the reader to consult this document for overall design and fixing advice, although selected parts of that information are repeated here. The appropriate design will depend on your particular needs and circumstances. You should get advice from the relevant qualified specialists where required. 2.2 Purpose of flashing The purpose of a flashing is to make the building weatherresistant and to prevent water from entering the building by diverting it. Flashings and cappings are strips of metal formed to weatherproof the edges of roofing and walling. For the purposes of this chapter, only the term flashing is used. The following sections should be considered as a guide only. For a comprehensive account of flashing guidelines, refer to HB Similar methods of flashing are used for different cladding-profiles. You can adapt the principles to suit your application. In all cases it is important to have ample cover provided by the flashing and proper turn-up of the cladding underneath. Be careful when moving between supports. Do not walk in the pan immediately adjacent to flashings or translucent sheeting. Walk at least one pan away. Lysaght has a range of standard flashings. We can also supply custom flashings to your requirements ask your local service centre for details. Flashings are required to provide weather-resistance for the various junctions on a roof or wall structure. Flashings are an important part of the cladding design, and have a significant impact on the aesthetic appearance of the building. Qualified tradesmen or other suitable expertise should be sought when designing, cutting and fastening flashing to a building. Ponding of water and build-up of debris should be prevented and all flashings should be designed to prevent this from happening. Flashings must be designed to provide weather-resistance for the roof or wall cladding, independent of the use of sealants or other materials to provide such weather-resistance. Unpainted galvanised steel is incompatible with most inert materials and is subject to inert catchment corrosion. 2.3 Materials and finishes Flashings, ridge cappings, and accessories should be made from the same material as the material used to clad the roof or walls. If different materials are intended or specified, such materials should compatible for both contact and run-off. Our most widely used cladding profiles are listed in Tables 2..1 and They are available in colorbond pre-painted steel, or in unpainted zincalume aluminium/zinc alloy-coated steel. FLASHING GUIDE 4

5 Typical material specifications colorbond is pre-painted steel for exterior roofing and walling. It is the most widely used. The painting complies with AS/NZS 27:2013 and the steel base is an aluminium/zinc alloy-coated steel complying with AS 1397:2001. Minimum yield strengths are G550 (550MPa), or G300 (300MPa) depending on the profile. Minimum coating mass is AM0 (0g/m 2 ). colorbond ULTRA is pre-painted steel for severe coastal or industrial environments (generally within about metres of the source). The painting complies with AS/NZS 27:2013 and the steel base is an aluminium/ zinc alloy-coated steel complying with AS 1397:2001. Minimum yield strength is G550 (550MPa). Minimum coating mass is AM0 (0g/m 2 ) Stainless steel standard grade designation is AISI/ASTM Type 430; UNS No. S43000 Not available in metallic finishes as a standard item. Subject to enquiry. The colorbond pre-painted steel complies with AS/NZS27:2013. Check with your local BlueScope Lysaght office for availability of profiles, materials, finishes, colours, accessories; and for suitability of the product. Tables 2..1 and list general information for profile selection. Refer to our publications on specific products for detailed specifications. There are also publications on zincalume steel and colorbond pre-painted steel from our information line (Page 1). 2.4 Compatibility Contact with, or runoff from, some materials can damage coated steel products. Buildings can also be susceptible to condensation on inside surfaces. The materials include certain metals, treated timbers and chemicals. Don t allow any contact of coated steel products with incompatible materials. Don t allow discharge of rainwater from incompatible materials onto coated steel products. Ensure that supporting members are compatible with the coated steel products or, alternatively, appropriately coated. Incompatible materials include: lead, copper, monel metal, bare steel, stainless steel (except with colorbond stainless cladding), carbon (in pencils and some rubbers), green or some chemically-treated timber (like CCA or tanalith treatments), materials subject to cycles of dryness and wetness or which have excessive moisture content (such as improperly-seasoned timber), wet and dry concrete, soils, vegetable matter, cleaning agents (e.g. brick cleaning) and any material which will inhibit normal exposure to the atmosphere. When moisture is present and two dissimilar metals are in contact, accelerated galvanic corrosion can affect one of the surfaces. This type of corrosion can also occur when water flows over dissimilar metals. Properly designed flashings help to keep the cladding dry and help to divert moisture and debris away from joins. To avoid ponding, all flashings should have a minimum fall of 1.5. Roofers and designers should consider compatibility issues when selecting materials in a roof or wall system Furthermore placing solar collectors, air-conditioning units or walkways on top of roof cladding need to consider discharge from such systems. Severe corrosion may occur If materials are not combined correctly. Lead flashing is not recommended, however it will usually be retained when re-roofing, because it is usually cemented into the structure. In these cases: the top surface of the lead flashing must be painted with a good quality exterior paint system (to limit contamination with lead compounds in water running off the flashing); and there must be a barrier between the lead flashing and the cladding: either a plastic strip (such as polyethylene damp course), or paint. Flashings should conform to AS/NZS :1994, and be compatible with the cladding (Section 2., LYSAGHT Roofing & Walling Installation Manual). Materials for flashings are available in zincalume or colorbond finishes. 2.5 Support spacings The maximum recommended support spacings are shown in Tables and of the LYSAGHT Roofing and Walling Installation Manual. They are based on data in accordance with AS 62.1:1992 Design and installation of sheet roof and wall cladding: Metal, and AS :1992 Methods of testing sheet roof and wall cladding Resistance to concentrated loads. The spacings in the tables are recommended to produce adequate performance of claddings under concentrated loading (incidental for maintenance). For support spacings in wind conditions, refer to our publications on specific products for wind pressure data. In all cases, cladding is fixed to a support of 1.0mm minimum base metal thickness (BMT) and minimum yield stress of 550MPa. If you want to use metal battens thinner than 1.0mm, seek advice from our information line. 2.6 Maximum lengths of roofing The valleys (or pans) of roofing have to carry water to the gutters. If the valleys overfill in heavy rain, water can flow into the roof through the side-laps and flashings. Factors affecting waterproof and drainage capacity of the laps of a profile include: the width and depth of the valleys or pans; the pitch of the roof rain flows faster on a steeper pitch; rainfall intensity for the geographical area; the length of the roof from ridge to gutter; and penetrations that cause nearby valleys to carry extra rain diverted from valleys obstructed by the penetration (Figure ). The maximum recommended roof lengths for drainage for each profile are given in Table of the LYSAGHT Roofing and Walling Installation Manual. FLASHING GUIDE 5

6 2.7 Low roof pitches Unless there is adequate positive fall in a roof, there is danger of ponding, which can lead to a reduced service life, particularly in coastal areas. At low slopes, say around 1 in 50 (1 ) slope, all roof supports must be in the one plane because slight variations can result in zero or negative fall. This may occur even after completion of the building as the result of settlement, timber warping or shrinking, or extra loadings (like air conditioners). Minimum recommended roof slopes are listed in Table of the LYSAGHT Roofing and Walling Installation Manual. As a guide, wherever possible, you should design for a minimum slope of 1 in 30 (2 ). Roof slopes lower than the recommended minimum may be available subject to enquiry and will be dependent upon the roof application and building details. 2.8 Wind forces on roofs Winds create considerable forces on both the topside and the underside of roof cladding, and you must consider these forces in the design and fixing of any roof. The forces are: inward forces tending to collapse the roof cladding inwards, caused by wind acting directly on the windward side; and outward forces tending to lift the roof cladding from its framing, and the entire roof structure from the rest of the building. Outward forces can be caused both by uplift from negative wind pressures, outside the building; and by positive wind pressure inside the building. Generally the greatest wind forces imposed on roofs are due to the outward forces. Because the dead weight of roofing materials is relatively small, the outward forces must be resisted by the roof fasteners. It is very important that the battens and roof framing are adequately fixed to the rafters and walls, and that claddings and flashings also be fixed to withstand these pressures. 2.9 Codes and performance tests AS 62.1:1992 specifies the design and installation of sheet metal roof and wall cladding. Our roofing profiles satisfy all the requirements of this standard, including the ability of the roof to resist outward forces and concentrated loads. The testing is performed according to AS :1992 and AS :1992. Flashings and cappings, although not tested separately, must comply to the fixing requirements of the cladding to deliver equal performance. FLASHING GUIDE 6

7 2. Specifications - roofing Table 2..1 Specifications of roofing & walling profiles Maximum recommended spacing of supports ROOFS Eaves Overhang 3 WALLS CUSTOM ORB CUSTOM BLUE ORB CUSTOM ORB ACCENT 21 * * * CUSTOM ORB ACCENT 35 FLATDEK 5 FLATDEK II 4 INTEGRITY KLIP-LOK 406 KLIP-LOK 700 HI-STRENGTH KLIP-LOK CLASSIC 700 LONGLINE 305 (not tapered) 5 5 SPANDEK SPANRIB TRIMDEK, unless otherwise marked (*) * which are indicative masses only. 2 See Section 2.5, LYSAGHT Roofing & Walling Installation Manual. 4 FLATDEK & FLATDEK II are Home Improvement profiles. Please refer to their individual brochures for more installation details. 5 Slope of 2º (1 in 30) is available subject to enquiry. Please refer to Section 2.5, LYSAGHT Roofing & Walling Installation Manual. FLASHING GUIDE 7

8 2.11 Specifications - walling Table Specifications of profiles for walling only Overhang mm EASY-CLAD MINI ORB 4 MULTICLAD PANELRIB 3 TRIMWALL 2 WALLCLAD Roofing & Walling profiles Walling profiles only FLASHING GUIDE 8 Step O ES IS IS ES O Spacing definitions ES = End span IS = Internal span O = Overhang Single span

9 3. Roof Flashing 3.1 Design All roof cladding located at the join (except gutters), require a flashing fastened on both sides of the join. Flashings near the edges of roofs or walls can be subjected to suction or negative wind loads that can be greater than other positive imposed loads. Therefore the wind design load can be approach double that of the main roof area, and as a result additional fixings are required to fasten flashings. The design wind load of each structure determines the number and the spacing of flashing fasteners as well as locate wind zones on the building. A minimum number of fixings are required to avoid flexing fatigue cracking of metal cladding under changing loads. This also prevents noise or flapping. Lysaght recommends screws instead of rivets for fastening flashings. The larger diameter of a screw shaft gives a greater shear capacity, and the larger head (or a washer) can be used to reduce the likelihood of pull out of the fastener. The penetration of rain into the roof or wall through the flashings is largely caused by the air pressure differential between the outside and inside of the roof or wall. Gusting wind can cause a significant pressure differential which can fluctuate greatly. This in turn can cause a pumping action where water can be sucked into the join which the flashing is protecting. Solutions to this problem include an anti-capillary offset fold, a gap of up to 5mm, or a suitable sealant. All flashing edges require one of these measures to avoid capillary action where flashings are subject to wind action when in contact with the roof or wall cladding. Flashings, other than standard ridging, are produced to specific order and are designed and manufactured from flat sheet or coil. If these flashings are required to match the colour of the profiled cladding sheets it is necessary for the pre-painted flat sheet or coil to be made by the same manufacturer using the same process in order to avoid differential colour matching or fading. Preferred maximum length of flashing is 6m, with expansion joints provided after a maximum of two lengths of flashing (12m) have been fixed together, as any lap secured by rivets or screws effectively becomes one length. Flashings are restricted in length in the same manner as are roof and wall cladding sheets and are subject to the same requirements and expansion provisions. A minimum distance of 2-5mm from the edges of all flashings must be provided away from an adjacent horizontal surface. This helps avoid the retention of moisture and deterioration at the cut edge of flashings. When a cut edge is very close to some materials (concrete, plaster or some rubbers) this spacing is particularly important. A minimum clearance (CL) of mm and a maximum clearance of 50mm should be provided at the end of wall cladding. The cladding should not extend down to any apron flashing. Figure 3.1 Barge C = Minimum cover Cl = Clearance c c Clearance c Clearance c Clearance Figure Vertical apron Smooth cladding Clearance Profiled cladding Smooth cladding Figure Parapet Profiled cladding These drawings are based on drawings from the NZ METAL ROOF AND WALL CLADDING CODE OF PRACTICE (Version 2.2: 2012). FLASHING GUIDE 9

10 3.2 Roof flashings Chased apron Vertical cladding Stop end turned down Diverter Figure Chased apron Figure Vertical cladding Angle diverter Stop end turned down Angled apron 1º Stop end turned down Figure Angle diverter Figure Angled apron 1º Angled apron 45º FLASHING GUIDE Stop end turned down Figure Angled apron 45º Figure Two piece apron Two piece apron These drawings are based on drawings from the NZ METAL ROOF AND WALL CLADDING CODE OF PRACTICE (Version 2.2: 2012).

11 3.3 Flashing laps A lap is the part of a flashing that covers (or overlaps) any part of the similarly shaped component, and these can be described as an end lap, overlap or underlap. Laps should comply with the following criteria: an overlap must run over (not under); an overlap must run downhill (the direction of the water flow); water must flow over a lap (not into a lap); a lap must be self-draining (not relying on sealant); an overlap must be across the gradient or at a shallow angle; a lap must be mechanically (hard) fixed; a sealed lap must have a minimum of width of mm; 3.4 Apron flashing Do not fit cladding tight onto the horizontal surface of an apron flashing. This would collect dirt and debris and it will retain moisture. A minimum clearance of mm is required. 3.5 Longitudinal flashings Longitudinal flashings run parallel to the pans or valleys, and are made to suit the cladding profile (Figure 3.5.1). They should have an edge turned-down to dip into the pan or valley. Flashing Cover The minimum recommended cover of longitudinal flashings over cladding should be as follows: (as taken from HB ) Pierce fixed roof sheet Concealed fixed roof sheet 0mm min. Into full pan (2/3 pan covered) Figure Typical longitudinal flashings 11 FLASHING GUIDE

12 3.6 Transverse flashings Transverse flashings run across the pans or valleys (Figure 3.6.1). They usually have a stiffening lip, along the lower edge, which is turned-down to dip into the pan or valley. To maximise weatherproofing, the bent lip is profiled to fit. Every 4th rib (minimum) The turn-down for transverse flashings for the shallow corrugated profiles can be fashioned to fit the profile by either notching or scribing to match the corrugations, or lightly dressed into the valleys. The type of fashioning (if any) depends upon profile shape and the type of material used to flash. Fashioning is preferred for low-slope roofs. The turn-down for transverse flashings for wide panned cladding is always notched or scribed to fit over the ribs. Every 3rd rib (minimum) Flashing Cover Lysaght produces a range of standard flashings (hip, barge, apron). To increase weather-resistance, Lysaght recommends you maximise the overlap between flashings and claddings. Refer to Table in HB-39 for greater detail. Fixing of Flashings Longitudinal flashings shall be fastened at maximum 500mm centres. Transverse flashings shall be fastened in accordance with HB , as detailed below. Profile Recommended Fixing Spacing (min.) Custom Orb/Custom Blue Orb Every 4th rib Custom Orb Accent 21 Every 4th rib Custom Orb Accent 35 Every 2nd rib Klip-lok 406 Every rib Klip-lok 700 High Strength Every rib Klip-lok classic 700 Every rib Longline 305 Every rib Spandek Every 3rd rib SPANRIB Every rib Trimdek Every rib Every rib The above fastener spacing relates to the stitching of flashings to sheeting. It does not constitute the minimum number of fasteners required to fix the sheeting to purlins. Notching tools Hand-operated notching tools cut one notch at a time. Each tool matches only one cladding profile. There are two types of tool; their use depends on whether or not the edge of the flashing has first been bent down. Figure Typical transverse flashings Table Notching tools FLASHING GUIDE 12 KLIP-LOK 406 KLIP-LOK 700 HI-STRENGTH KLIP-LOK CLASSIC 700 SPANDEK, TRIMDEK Others subject to inquiry. Flashings provide the essential weatherproofing at the edges, and they sharpen the image of the finished job.

13 3.7 Using notching tools After the cladding is fixed and the turn-ups finished, proceed as follows. Place a flashing with the notch-edge resting on the ribs. Locate your notching tool over a rib with the notching head against the flashing. vertical tool: The body locates along the rib. horizontal tool: the lugs on the underside locates on top of the rib. Raise the handle to open the tool and: vertical tool: lift the flashing into the mouth of the tool; horizontal tool: slide the mouth of the tool over the edge of the flashing as far as it will go. Push down on the handle to perform the notching. Repeat for all ribs, checking in each case that the flashing is correctly positioned. If you are using a horizontal tool, bend down the tongues between the notches over a suitable straight edge (such as a piece of timber). Notching with tinsnips If notching tools are not available, flashings can be notched to the rib profile with tinsnips (Figure 3.7.2). The procedure is sometimes known as scribing. After the cladding is fixed and the turn-ups finished, proceed as follows. Figure Using notching tools Place the flashing with the turned-down edge resting on the ribs. Mark out the notching using a template positioned over each rib. Cut the notches with tinsnips. This procedure is also used for hip cappings. Fasteners for transverse flashings You must properly fix both flashings and the ends of all sheets. Where the cladding is pierce-fixed through crests, and the position of the purlin allows it, the fasteners used to fix the sheets, may also fix the flashings. On all other installations, pierce-fix your flashing to the ribs or crests of the sheets. Joining flashings The overlaps of transverse flashings should be sealed with a recommended sealant and fastened. Before finally positioning and fixing the lap, turn over the top piece and apply a 3mm bead of sealant across the flashing, about 12mm from the end. Figure Using a template to mark out for notching with tinsnips FLASHING GUIDE 13

14 3.8 Flashing at change of pitch Figure Typical flashing at changes of pitch 3.9 Capped bent ribbed roofs Tray cladding can be used in continuous lengths from eave to eave by cutting the ribs and bending the pans at the ridgeline. The same process is used on Mansard roofs. Caps are fitted over the cut ribs, which open up when the pans are bent. Fitting the rib caps can be time-consuming and care must be taken with sealing to avoid any possibility of leakage. The ribs must be cut squarely, with a metal cutting blade in a power saw, set to the depth of the rib minus 2mm. In some states pressed steel caps may be available to suit klip-lok ribs, though the range of angles is limited. Caps can be handmade to suit any angle from flat sheet. klip-lok is most frequently used for capped bent ribbed roofs, but longline 305, trimdek or even spandek can be used. For these four profiles the rib caps can be made from pieces of rib profile cut from a short length of cladding. A neutral-cure silicon sealant should be used. FLASHING GUIDE 14 Figure Capped bent ribbed roof and on flanges.

15 3. Gutter apron Where the ends of roof cladding are exposed to environmental contaminants such (industrial pollutants, sea salt) provide an over flashing which discharges into the gutter. (see Figure 3..1 & 3..2) Benefits of gutter apron: Protects to the underside of the roof cladding/ underlay. Provides support for the roofing underlay which can be damaged by wind and solar radiation. There is an air gap between the spouting and the fascia where PVC spouting is used, caused by the thickness of brackets. In areas exposed to sea air, a gutter apron can minimise the risk of corrosion of the unwashed area. Can be used if there is no spouting or it has a low front. Protection against wind-blown embers. Contaminants can be driven up the ribs of the cladding if exposed in a severe environment. Metal flashings or profiled foam fillers can be used to prevent or reduce this. The over flashing should extend 50mm into the gutter and the underlay finishes on the down-side of the flashing. Extend the underlay into the gutter by a minimum of 20mm if there is no over flashing into the gutter. Figure 3..1 Gutter apron: Quad Figure 3..2 Gutter apron: Trimline/Sheerline These drawings are based on drawings from the NZ METAL ROOF AND WALL CLADDING CODE OF PRACTICE (Version 2.2: 2012). FLASHING GUIDE

16 FLASHING GUIDE Types of penetration flashing design Penetration flashings can be divided into four different types. Type A Under flashings drain at the plane of the roof pan. Soaker (under) flashings Suitable for any pitch; Most preferred detail; Curb side in line with the rib; Leave clearance of mm (minimum) all around; minimum of 0mm for all upstands; Drill holes for rivets before sealing; minimum mm for sealed laps; Order slightly longer cladding sheets to allow for lapping; Type B Overflashings drain at the plane of the rib of the roof. These are also known as back flashings. Simple to use Suitable for use to first purlin from the ridge if > 300mm wide. Not suitable for widths over 1.0m regarded as unattractive by some Suitable for use with sprung or over-roof design. Type C Tapered flashings that drain at the plane of the roof pan at the top, and over the ribs at the bottom. Also known as transition or under/over flashings. Tapered or transition flashings Provides greater water run-off capacity Suitable for all roofs > 5. Can be used for a retrofit Support required Type D Type A Under soaker Type B Over watershed Soaker flashings that drain at the plane of the roof pan at the gutter Simple Provides greater water run-off capacity Suitable for all roofs > 5 Can be used for a retrofit Support required Limited to 1.1m wide and 2.4m long Type A Under soaker Type B Over watershed Type C Under/over tapered Type D Tray These drawings are based on drawings from the NZ METAL ROOF AND WALL CLADDING CODE OF PRACTICE (Version 2.2: 2012).

17 3.12 Flashing large roof penetrations Penetrations through ribbed cladding block the valleys (or pans), and thus affect the free flow of rainwater down a roof. All flashings have to weatherproof the cladding but on the uphill side of large penetrations, they also have to channel rainwater sideways into valleys that run unobstructed to the eaves. Four methods are described here. In all methods the ends of cut ribs may be closed off with caps on the outside of the rib, or with plugs inside the ribs. Plugs must be used on side-laps to allow the anti-capillary cavity to drain. Note: For masonry construction, Building Code Australia (BCA) requires the use of Damp Proof Course (DPC) to ensure weather-proofing. For acceptable methods see BCA section on weather-proofing masonry. Support framing Wherever one or more of the sheet ribs are cut, you must provide framing to support the cut ends of the roof cladding each side of the penetration. Existing flashing If you have to re-use lead flashings that are built into the structure, special protection is needed. Method 1: Head gutter and apron flashings This is often the simplest method, and commonly used for existing protrusions (Figure ). Method 2: Flat tray and sleeve To avoid fitting and sealing end caps to all the sheet ribs on the low side of the penetration, an apron flashing can be fitted to the sleeve and sealed to the tray each side. Figure Flashing method 1: Head gutter Figure Flashing method 2: Flat tray and sleeve FLASHING GUIDE 17

18 Method 3: Tray gutter for steeper roofs If the roof pitch is more than, say 1 in 12 (5 ), you cut the roof cladding sufficiently high above the penetration to allow a tray gutter to raise rainwater over the top of the sheet ribs and divert it around the penetration (Figure ). Figure Flashing method 3: Tray gutter for steeper roofs Method 4: Penetration close to ridge capping If a roof penetration is close to a ridge capping (or flashing above the penetration), you can fit a simple flat tray, on top of the roofing, so that it extends from under the capping down to a sleeve around the penetration. FLASHING GUIDE 18 Figure Flashing method 4: Penetrations close to ridge capping

19 3.13 Flashing small roof penetrations A flanged cylindrical sleeve is a fairly simple method of flashing around small penetrations (such as pipe penetrations) which fit between the ribs of a roof sheet, or penetrate only a single rib. Two methods are described here. Wherever roofing is cut, you must consider providing extra support for the roofing above and below the penetration. Where one or more of the sheet ribs are cut, you must provide framing to support at the cut ends of the roof cladding each side of the penetration. Method 1: Tapered metal skirt and sleeve This method uses parts custom-fabricated from metal. There is no positive seal between inside the building and the outside atmosphere (Figure ). Method 2: Sleeve This is often the simplest method (Figure ). Flexible flanged sleeves can be bought for flashing around penetrations of at least 350mm diameter. They overcome the problem of capping and sealing the open ends of cut ribs. A sleeve is commonly used, though silicone sealant has a wider operating temperature range and is available in a wider range of colours. The flange around the base of the sleeve can be contoured by hand to match the cladding profile before it is sealed and fixed to the cladding. Be careful not to dam any valleys or pans so that rainwater can drain freely from the high side of the roof penetration. Moisture held in such areas can cause deterioration of the sheet coating, reduced life expectancy or poor appearance. Where damming of any valley or tray is unavoidable, due to the size of the pipe penetration, treat the installation as a large penetration. Copper penetrations All copper pipe penetrations through zincalume or colorbond steel cladding must be physically and electrically isolated from the cladding. This can be done by using a sleeve of PVC polyethylene or similar plastic that is also ultra-violet stable. Figure Small penetration with metal skirt and sleeve Figure Small penetration with sleeve (Dektite sleeve illustrated) 19 FLASHING GUIDE

20 3.14 Expansion Background on thermal expansion All metals expand and contract with changes in temperature. Although steel is by far the least affected of all the metals commonly used for roof and wall cladding, the changes in length experienced in very long runs of roofing are significant. On a clear hot summer day, with no wind, the steel temperature in roof cladding can reach approximately 50 C in colorbond surfmist, 60 C in plain zincalume and more than 80 C in colorbond night sky. Examples of the thermal changes in lengths of steel cladding that would result from various temperature changes in the steel are shown in Table The actual expansion or contraction between the end of a sheet and the last support would only be a fraction of the figures shown because the movement in the length of fixed cladding would normally take place from the centre towards each end of the sheet. The movement at each end is thus only half the total expansion or contraction. Transverse thermal expansion poses no problems in ribbed cladding because each rib absorbs some transverse movement. Expansion joints Thermal expansion effects are mitigated by slight bending of fastener shanks, thermal movement of the building structure, and slight flexing of the purlins (where they are not restrained by cleats or bridging). However, for very long runs of roofing, you should include an expansion joint to overcome linear thermal expansion. Table shows the maximum distance between the top and bottom rows of fasteners on a pierce-fixed sheet. For LONGLINE in distances of greater than 35m, please contact your Lysaght branch for advice. If the total length of two sheets pierce-fixed through the lap, or a single sheet exceeds this distance, then an expansion joint is needed. There should be no more than one pierce-fixed end-lap between expansion joints. An expansion joint involves overlapping the ends of the upper sheets over the ends of the lower sheets but with a clearance between them (about mm). A typical overlap is 0mm (this overlap is not the same as the overhang in Table which does not apply to expansion joints). The clearance is usually created by having all the purlins for the roofing on the high side of the joint, higher than the roofing on the low side of the joint. An extra purlin is needed at the joint. A baffle flashing provides weatherproofing. See Figure Where there is a risk of high winds, or the ribs result in a large opening, you may need protection, such as extra flashing or the inclusion of closed-cell foam infill strips. Table Thermal expansion and contraction of steel cladding Table Maximum distance between top & bottom rows of fasteners on a sheet, before expansion joint is needed Sheeting turned down Baffle flashing. Notch over ribs & fasten to underlapping sheet Figure Expansion joint detail /pans Added protection if required 0 mm minimum overlap Trays turned up 300 mm Depth of sheeting plus mm mm min. clearance FLASHING GUIDE 20

21 3. Standard roof flashings LYSAGHT Standard flashings by region Although some flashings are common to all regions, the climactic conditions can cause variations in the local product requirements. Please check with your local Lysaght sales representative for the product offer in your area. Other flashings are available as special orders. New South Wales Barge capping Ridge capping *Nominate roof pitch CUSTOM ORB, BLUE ORB & ACCENT TRIMDEK & SPANDEK CUSTOM ORB, BLUE ORB & ACCENT * TRIMDEK & SPANDEK * Apron flashing CUSTOM ORB, BLUE ORB & ACCENT TRIMDEK & SPANDEK KLIPLOK & SPANRIB Valley flashing Valley flashing * Ribbed valley º 2 2 Structural valley KLIPLOK KLIPLOK * CUSTOM ORB ACCENT º Valley support CUSTOM ORB ACCENT Barge roll dia mm length only Barge roll capping mm length only CUSTOM ORB ACCENT * CUSTOM ORB, BLUE ORB & ACCENT * Tile flashing 35 CUSTOM ORB, BLUE ORB & ACCENT 21 *Nominate 230 * deg 140 angle 20 TRIMDEK & SPANDEK 220 * deg Barge gutter Spear point KLIPLOK & SPANRIB 2 * deg CUSTOM ORB ACCENT 35 2 * deg FLASHING GUIDE

22 Victoria Side capping Baffle flashing Ridge capping Valley gutter Counter flashing Barge roll Tasmania Barge capping Ridge capping Ridge capping Valley flashing Miscellaneous flashing Queensland Single-sided ant capping Horizontal ant capping Round vent stays Tile valley gutter Roll-top ridge capping Double-sided ant capping Window flashings/ Door heads Roll-top barge capping Ridge capping - three break Gable roll FLASHING GUIDE 22 Bribie Island ant capping Drip strip Valley gutter - three break Barge gutter

23 Western Australia Bargemould/corner capping Corner flashings Barge capping & parapet flashing Ridge capping KLIP-LOK Barge º Adjustable box gutter brackets º Roll ridge to suit fibreglass & plastic curving sections º Spandek gutter boards 550 or 770mm wide º Valley gutter º South Australia & Northern Territory Roll top ridge capping Ridge capping Valley gutter Barge capping Barge roll SPANDEK & TRIMDEK SPANDEK & TRIMDEK Spandek gutter boards Barge gutter 23 FLASHING GUIDE

24 3.16 Non standard roof flashings, cappings and gutters This page shows some non-standard profiles. Please ask your local Lysaght branch for other options. G irth range (mm) Preliminary Check with your local Lysaght Service Centre for: 1. Available girth range 2. Available colours 3. Profiles not shown 4. Maximum lengths 5. Lead times 6. How to handle tapered flashings Order requirements On a sketch show 1. Profile type 2. Colour (or zincalume steel, or galvabond if not colorbond steel) 3. Side on which colour is to be (use letters shown below) 4. Dimensions (use letters shown below) 5. Angles on all bends that are not 90 degrees 6. Quantity and lengths Profile types Type 1 (CF1) B C Type 5 (CF5) Type 9 (CF14) A Type 12 (CF32) A Type 2 (CF2) C B A D E F G D H A B Type 6 (CF11) A B C C D B C Type (CF) A B E D D A B Type 13 (CF33) A C Type 3 (CF3) B C D Type 7 (CF12) A B C D E A C Type 11 (CF31) B C D E A Type 4 (CF4) C B D Type 8 (CF13) A B C B C D Type 14 (CF35) A B C D A FLASHING GUIDE 24 (Up to 400mm girth)

25 3.17 Box gutters Lysaght standard design Box gutters are designed to suit large water carrying capacity requirements, usually on commercial buildings. In effect, a box gutter operates like an open drain. Designing for a box gutter requires adequate support for the gutter be provided, both at the sides and below, to provide for the anticipated weight of the water collected. As with all gutters, adequate fall must be provided as well as a rainhead or other large capacity drainage system. Box gutter Box gutter Figure Box gutter FLASHING GUIDE

26 3.18 Barge Gutters and cappings Barge gutters are designed to provide an option for the rainwater carrying capacity for the sides of buildings. This detail is the most common way to flash the side of a steel clad roof. Barge flashing 0mm 0mm Barge 0mm Flange to match profile depth Barge flashing 0mm Purlin 2-piece seamed barge capping required for curved roofs Barge Figure Barge gutters and cappings FLASHING GUIDE 26

27 4. Typical wall flashings 4.1 Cladding orientation Cladding is usually installed with the profile running vertically or horizontally, though sheets have been laid diagonally the choice is aesthetic. Wind can drive rain hard against wall flashings, so it is important that you pay attention to the detailing of flashings around windows, doors, re-entrant and external corners, to ensure you get a watertight building. You also want a neat appearance. We make wall flashings for some wall claddings (like easyclad and mini orb) which are sometimes called trims. Where these are not suitable, custom-made flashings can be easily produced following the general principles described in this section. 4.2 Walling profile running horizontally It is usual to lay the first sheet at the bottom of a wall and work upwards towards the eaves. You want the window and door flashings to fit properly into the valleys, so you should locate the first sheet relative to the heads and sills of doors and windows. Thus, you first have to decide where the cladding will eventually be located at the heads of doorways and at the heads and sills of windows before you place the first sheet. Where possible, select the vertical size of windows so that the flashings at both heads and sills will coincide neatly with the pitch of your profile Be sure that the crests of the profile align with each other on adjacent walls, either side of a corner this ensures that horizontal flashings fit properly into all valleys. Where valleys create a void at flashings, use closed-cell foam plastic infill Where wind-driven rain can be expected, turn back the edges of flashing to restrict water movement past the flashing. Continuous beads of silicon Direction of water flow 0-200mm overlap Straight overlap flashing Continuous beads of silicon 200/300mm Soaker (underlap) flashing mm mm (mm min.) mm Openings Maximum as recommended for profile Figure Types of flashing laps 50mm minimum Minimum fall for drainage 5º Minimum fall for drainage 5º Sheet Overhang Recommended Minimum Drainage Flashing is fixed using self drilling screws or rivets. Fixing as close as possible to the edge reduces distortion. Wind exposed areas near the edge of the building may require additional fixing. FLASHING GUIDE 27

28 4.3 Types of flashings mm minimum 35º typical mm minimum A small gap may remain after crushing. mm minimum to suit depth of profile mm minimum 135º typical mm minimum Drip Edge Flatten Edge Break Mountain Fold Turn Down Figure Edge types 0/0mm 0/0mm Roof Underlap Roof Overlap 0/0mm 0/0mm 0/0mm Drip edge Vertical Wall Underlap Vertical Wall Overlap Vertical Wall Overlap FLASHING GUIDE Wall Side Underlap (Horizontal sheeting) Figure Types of flashing laps 50/0mm 50/0mm Wall Side Overlap (Horizontal sheeting) 50/0mm

29 Optional wall trims Available in zincalume steel or colorbond steel* CD 1 Trim Channel CD 3 Fascia to Soffit Section, CD 4 Feature Section Soffit 50CD 5 External Corner. Use 19 Use with Multiclad, Use with Panelrib, 16Mini Use with Panelrib, Mini 8 orb, with Panelrib, Multiclad Easyclad145 orb, Easyclad, MulticlaD Easyclad, Multiclad easyclad and Mini orb CD20 Butt joint trim-top hat CD6 CD 6 Internal Corner. Use CD 8 Purlin hat Section CD Tee Section. Use with CD 20 Butt Joint trim - Top with Panelrib, Multiclad Use with Multiclad, Easy- clad CD20 External Butt corner joint trim-top hat clad CD6 and Internal Mini corner orb. Panelrib, Multiclad easy- Hat. Use with Panelrib, 48 ernal corner easyclad CD24 Internal and Mini corner orb. CD23 CD5 External Multiclad corner and Mini CD24 orb. Internal corner C CD22 Edge trim 18 (Subject to enquiry in SA) 46 CD 26 In CD22 Edge trim al atcorner CD CD21 CD6 Internal Butt Joint joint corner trim-overlap Trim CD20 - CD5 Butt External joint CD trim-top 22 corner (Subject to enquiry in SA) Edge Trim Use CD24 with Internal corner CD Internal CD23 External corner Corner. corner CD Use External CD corner17 20 hat CD6 Internal corner CD5 External corner 24 CD24 Internal CD21 Corner. corner Butt joint Use trim-overlap CD23 External Overlap. Multiclad and Mini orb. with Panelrib, Multiclad with Panelrib, Multiclad Use with Multiclad (Enquiry 48 only in S.A.) 33 easyclad and Mini orb. easyclad 33 and Mini orb CD22 Edge trim A) CD 26 Internal corner CD External corner (Subject to enquiry in SA) CD21 Butt CD joint 26 trim-overlap Internal 27 corner CD External corner 27 CD21 Butt joint trim-overlap CD 27 Fascia to Soffit CD 30 Fascia Capping. Use CD 39 Trim Channel EC 3 Fascia Capping. Use Section. Use with Panelrib, with Panelrib, Multiclad, Use with Easyclad. with Panelrib, Multiclad, Multiclad, Easyclad 145 and trimwall, easyclad and trimwall, easyclad and Mini orb. Mini orb. Installation - Concealed Fastener Mini orb First Sheet Our range of wall trims are available for the range of CD 40 Clip Interm LYSAGHT cladding profiles to provide an attractive compliment 20 to walls, ceilings or soffits Some trims are used to start the installation of the walling panels whilst others provide the perfect finishing touch. First Sheet CD Trim 40 channel Final Made from Colorbond or zincalume steel*, they Starter Clip are an attractive, long lasting addition to any walling Use with Easyclad. installation. 30 Not all trims are available in all locations and some dimensions may vary from state to state - for local availability of wall trims, contact your local sales office. 2.5 *Other materials, such as stainless steel and Colorbond Ultra are available, subject to enquiry. FLASHING GUIDE 29

30 4.5 Mid wall connections Depth to suit profile 50mm minimum flange Wall supports Continuous silicon seal 30mm min. Depth to suit profile 50mm minimum 4.6 Internal wall connections FLASHING GUIDE 30

31 4.7 External corner connections 50mm typical 50mm typical External Corner Trim To suit profile To suit profile To suit profile 50mm typical 50mm typical 50mm typical To suit profile 50mm typical To suit profile 4.8 Flashing for horizontal cladding 50 (75 without crush and fold) Flush head Flush under jamb Flush sill 50 (subject to corrugation) Flush jamb 50 FLASHING GUIDE 31

32 4.9 Flashings for horizontal corrugate cladding Extra care and attention to the detailing and fixing of horizontally oriented corrugate cladding is required. Designers using horizontally fixed corrugate sheets as a design feature should recognise that there are a number of requirements which differentiate horizontal from vertical profiled cladding. Horizontal cladding exposes the defects in the visual appearance of the framing to a much greater extent than vertical cladding does. The plane of the supports both horizontally and vertically should be straight within a very limited tolerance (5mm in metres) The vertical and horizontal planes of framing members should exhibit little or no twist. Therefore, the standard of framing should be inspected and approved the before the commencement of any cladding installation. Horizontal cladding should be fixed in the pan as this provides a stronger, more economical and aesthetic fastening than crest or rib fixing. The wind design load for the building will determine the number, spacing and the position of the fasteners. A butt detail to join horizontal cladding which is simple and aesthetically pleasing is to provide a vertical break at structural steel frame centres. Use a top hat or tee flashing section at the join, but ensure the exact sheet length required is used. These sheets must be cut accurately to within 1mm to provide a neat joint. Condensation is likely when horizontal metal cladding is directly fixed to a lined or insulated wall. Therefore it is recommended that horizontal laps are sealed with sealant or lap tape. 4. Flashings for vertical cladding Detailing flashing for vertical cladding is similar to detailing roof cladding penetrations. This is because the water from the under has to drain over at the window or door head. Automatic weathering is provided by a sheet lap at the head flashing. Either profile the vertical upstand of the head flashing or flatten the lap. This detail can be used for corrugated, ribbed and trapezoidal cladding. Do not stop end the flashing but turn it down as per drawings 4..1 and mm 50mm mm mm 50mm Figure 4..1 Flashings for vertical cladding 50mm mm mm 50mm 50mm External Corner 0mm crush and fold to be flattened over a spacer bar Internal Corner FLASHING GUIDE 32 50mm 50mm mm 50mm mm mm 50mm 30mm Tee flashing Jointer Figure Butt details These drawings are based on drawings from the NZ METAL ROOF AND WALL CLADDING CODE OF PRACTICE (Version 2.2: 2012).