1 Avoiding slips trips and falls Tiles, stairs, ramps and handrails By Richard Bowman Image courtesy of Stoneplus/Cairns Marble. When slip and fall accidents occur on stairways and ramps, the injuries are generally more severe than accidents that occur on level surfaces. Although the Building Code of Australia 2007 (BCA) has some physical requirements for stairways and ramps, many aspects are not covered. Furthermore, the tiling of stairs is not covered in AS : 2007, Ceramic tiles: Guide to the installation of ceramic tiles. ASTM Committee F13 on Pedestrian/Walkway Safety and Footwear, has tentatively defined a slip-resistant walkway surface as a walkway surface that provides more than the required friction, for the range of pedestrians who will be using it under the range of reasonably foreseeable conditions, wearing the type of footwear that is expected under normal ambulation conditions, and are behaving in an expected and predictable manner. While individual and behavioural influences contribute to fall events on stairs, poor design and construction are also principle causes. Inconsistent step dimensions, inappropriate step sizes, inadequate handrails and poor step visibility are the four main problems. Tiling contractors should be as informed as possible and any necessary requirements should be explicitly detailed in the specifications. Stairs with one or two steps, inappropriate geometry, or non-uniform dimensions, and stairways with poorly designed or no handrails are implicated in a high number of fall-related injuries and deaths. Irregularities in ramps can lead to stumbles and falls, which can result in runaway laden shopping trolleys and wheelchairs. These problems can be compounded by unsuitable handrails. Tiling stairways and ramps has its own challenges, as does installing handrails and balustrades through existing tiling, particularly if a waterproof membrane will be penetrated. Neither is the detailing of penetrations through tiling. In order to determine best practice, it is useful to consider the local and international building regulations and what they require of stairways and ramps before considering some specific tiling issues. While the BCA costs $220 (www.abcb.gov.au) and AS , Design for Access and Mobility: General requirements for access New building work, $ (www.saiglobal.com/shop/script/details.asp?docn=as ), the Americans with Disabilities Act and Architectural Barriers Act Accessibility Guidelines (ADA/ABA) is freely available at www. access-board.gov/ada-aba/final.pdf. The ADA/ABA provides useful guidance if one is looking for good practice rather than strict compliance with the BCA and the Commonwealth Disability Discrimination Act 1992 (DDA). The BCA is published in two volumes. Volume Two contains the Housing Provisions and pertains primarily to Class 1 and 10 buildings detached houses, sheds, carports, etc. Volume One concerns Class 2 to 9 buildings and relates to other buildings, such as apartment blocks, office buildings, shops, hospitals, hotels, factories, etc. Both volumes of the BCA have access and egress requirements for stairs, ramps and handrails, where the objective is to provide safe, equitable and dignified access to buildings, and the services and facilities within them, as well as safeguarding occupants from injury during emergency evacuation (when water sprinklers might be wetting the stairs). Stairways and ramps must have slip-resistant surfaces, safe gradients, and suitable handrails to assist and provide stability to users. Stair treads must either have a non-slip finish or an adequate non-skid strip near the edge of the nosings. Stairway landings must either have a non-slip finish throughout, or an adequate non-skid strip near the edge of the landing where it leads to a flight below. While Volume Two requires most unbounded stairways to have continuous balustrades, Volume One requires handrails on at least one wall. Stairway geometry Since the BCA defines the permitted stairway geometry, it is relatively easy to determine whether or not stairways comply. The BCA deemed to satisfy provisions for stairways require there be not more than 18 and not less than two risers in each flight. The risers and goings are required to be constant throughout one flight, where the riser and going dimensions must be in accordance with the following Table 1 (other than spiral stairways). 26
2 Table 1: Riser and going dimensions (mm) Riser (R) Going (G) Quantity (2R+G) Pitch Stairway Max Min Max Min Max Min Max Public BCA Vol Public BCA Private BCA Vol Housing BCA Vol AS < RG 4800 (45) UK - Assembly UK - Public UK - Private NZ - Accessible NZ - Common NZ Private NZ - Service ADA-ABA Table 1 also includes the AS , Fixed platforms, walkways, stairways and ladders Design, construction and installation, industrial access requirements, and some British (BS ), New Zealand Building Code (NZBC), and American (ADA/ABA) requirements. Assembly stairs are frequently used by large numbers of people at the same time moving slowly, and so these steps should be designed with a large going and a small rise. Public stairs are used by people moving faster and unconstrained by other users, and so the rise may be greater. The rise for private stairs has often exceeded the current regulations since space was (and usually is) at a premium. Stair geometry is also influenced by the differences in gait on ascent and descent and by energy expenditure considerations. During ascent, the going should be large enough to allow at least part of the heel to rest firmly on each step. In descent there should be no need to place the foot at an awkward angle. John Templer, in The Staircase: Studies of Hazards, Falls, and Safer Design (MIT Press, 1992) considered the range of riser and going relationships for comfort and safety. He found that Because descent has been shown to be the movement direction that is most hazardous, the requirements for safe movement in descent should be of first importance. A reasonable compromise would be a stair with risers that are not less than 160 mm to suit ascent, and to suit descent, risers not more than 183 mm. In order to accommodate feet adequately on descent, goings should not be less than 279 mm. The British Health and Safety Executive have proposed that, during stair descent, at least part of the toes should be supported by the tread, when initial contact with the tread is made. Population data showed that a minimum going size of 250 mm is required for 50 per cent of the population to accomplish this. They therefore recommended that the minimum going size of private, public and assembly stairs should be increased to 250, 300 and 350 mm respectively. Although the Guide to the BCA states that the going and riser requirements date from a substantial reform in 1987, based on international research, the source or findings of this research is not evident. Prior to the BCA 1988, states had allowed a maximum rise of 190 mm; and the maximum going was typically 395 mm. The minimum going for all stairways was 250 mm in NSW and 255 mm in Queensland. The BCA 1988 introduced a lower maximum riser (180 mm) and an increased minimum going (280 mm) in public buildings. The 1993 amendments to the BCA reversed these progressive reforms, specialists in stone & tile modifications The Stone Cutters specialise in the manufacture of laminated bullnose materials that can be applied to a variety of polished or honed products including: ceramic, porcelain, marble, granite, limestone and engineered stone. We can manufacture special corners and curves to provide the perfect finish and profile to any pool edge or strair tread. Theses materials are manufactured and designed to last! resistant to saltwater and chlorine perfect colour match throughout, no cappings required The Stone Cutters can fabricate most of your tiling requirements including steptreads, scoring, aris & cuts, borders, panels, mosaics and tumbled marble. Contact us now to discuss display materials! Factory: 2/22 Mavis St, Revesby NSW 2212, Australia Phone: Mobile: or Fax: specialists in stone & tile modifications
3 contrary to the needs of accessible stairways. Although the NZBC has the most consumer friendly accessible and public dimensional requirements, the BCA has sensible private housing requirements. BCA Clause D2.13, Goings and risers, was and remains in the form of a performance requirement. Other geometries can be proposed to the regulators for accreditation. Where stairways are to be tiled, the use of dimensions that enable whole tiles to be used is generally preferable. The BCA no longer provides any guidance as to the acceptable deviations in tolerances between risers or goings in each flight. Until 30 December 2000, the BCA provided tolerance values of 5 mm variation in both the riser height and tread/going dimension. A variation of 15 mm was permitted in the first and last riser heights, recognising that changes in adjacent floor covering specifications effect finished stair dimensions. Such tolerances could also be applied where atmospheric moisture changes caused movement of materials (i.e. cupping of timber stair treads). However, They should not be applied to allow for poor construction practice. The NZBC requires that the Riser height and tread depth for all steps in one flight, shall be uniform within the tolerance of ± 5 mm. Templer also used this tolerance. BS 5606 suggests that a typical cast in situ concrete should have a variation between step rises of no more than 4 to 6 mm. Although tiles have dimensional variations, surface flatness is likely to be the most important criterion for step treads. The NZBC does not use the (2R + G) comfortable gait quantity as it does not always lead to safe stairway geometry and can exclude some safe moderate pitch stairs. BRANZ preferred to use a smaller range of 580 to 620 mm, and nominated a tread depth of 300 mm with 150 mm risers as the optimum dimensions. Within limits, the flatter the pitch, the safer the stair is to use. Stairs with a pitch line slope of less than 23 o do not permit people to use the stair with an acceptable gait. The BCA has two simple drawings, which define the going and the riser dimensions; both feature overhanging treads that have horizontal walking surfaces. The BCA does not mandate the maximum tread projection of overhanging treads. AS 1657 requires a minimum overlap of 10 mm with open risers. The NZBC requires a minimum 15 mm tread projection with open risers, and a maximum tread projection of 25 mm for both open and closed risers. The NZBC requires that accessible stair treads and risers be shaped to prevent the user being tripped as a result of a foot being caught under a tread projection during descent. This danger is inherent in stairs with high risers, narrow treads and projecting nosings. Templer advised against abrupt overhangs and overhangs greater than 19 mm. The ADA/ABA states Nosings that project beyond risers shall have the underside of the leading edge curved or bevelled. Risers shall be permitted to slope under the tread at an angle of 30 o maximum from vertical. The permitted projection of the nosing shall extend 38 mm maximum over the tread below. External stairways External stairways are generally built with a slight wash on the treads to drain water away from the nosings, where adequate traction is most important. The water could, for example, be drained to the back of the tread and then to an open side by having the slope in two directions, or it could drain each successive tread by sloping them toward the nosings. However, one should avoid a torrent of water flowing over the nosings towards the bottom of the flight. The BCA imposes a maximum gradient of 1 in 50 (a slope of 1.15º) on stairway landings, to make sure that the landing is as level as possible, but still allowing a slight slope for drainage if necessary. Although the BCA drawings show the stair treads as being horizontal, the BCA does not provide any guidance nor impose any requirements with respect to the slope on treads. BS requires horizontal treads. One traditional rule of thumb was a slope of approximately 1 per cent (one-eighth inch per foot or 0.57º). Templer stated that the slope should not exceed about 1 in 60 (1º). The TCNA Handbook still uses one quarter inch per foot (1 in 48) or (1.19º) as the nominal or minimum slope towards drains for tiling. The ADA/ABA does not permit treads to have a slope steeper than 1:48. The slope of the tread is most important, as it significantly affects the rise. Table 2 gives the additional distance that someone steps down as a function of a downwards sloping tread. The table extends to 6 o reflecting the wide range of slopes that I have measured on individual flights, where variations in the slope alone have accounted for differences of 20 mm between individual risers. Since stair users move each foot down two steps at a time, the cumulative differences (over two steps) can be quite large. Table 2: Additional step down distance at the nosing as a function of tread slope for a constant going of 250 mm. Slope (º) Distance (mm) This tread slope induced variation must be considered in the context of the ± 5 mm NZBC riser tolerance. This height variation increases as the going becomes greater, where the above distances should be increased by 20 per cent for a 300 mm going, and 40 per cent for a 350 mm going. However, the length of the going is little affected by a sloping tread. For a nominal going of 250 mm, the actual tread length only increases by 1 mm once the slope exceeds 5 o. Slip resistant design While there are several reasons why people fall on stairs, having adequate slip resistance is obviously a sensible requirement. However, how does one demonstrate compliance with the deemed-to-satisfy provision of treads which have a non-slip finish or an adequate nonskid strip near the edge of the nosings? Although the BCA is principally concerned with new buildings and renovations, compliance with the Federal Disability Discrimination Act 1992 (DDA) is required in areas of existing public buildings and many workplaces. Furthermore, the OHS legislation in individual states requires slip-resistant pedestrian workplace surfaces. Part D3 of Volume 1 of the BCA defines the access requirements for parts of buildings, where those parts of buildings that are required to be accessible must also comply with AS , which requires that accessible paths of travel be slip resistant. Clause 12 of AS contains a note Refer to AS 4586 and HB 197 for guidance on slipresistant surfaces. AS/NZS 4586, Slip resistance classification of pedestrian surface materials, provides examples of how to measure the wet pendulum slip resistance of unfixed nose step treads that have a raised profile at an irregular spacing, and stair tread tiles that have a recessed profile at a regular spacing. It is generally not possible to measure the in situ slip resistance of stair nosings, but one can measure the slip resistance of non-skid strip near the edge of the landing, albeit with difficulty. However, any non-skid strip is likely to comprise only a small fraction of the wet pendulum 126 mm test path length. The assessment of the skid resistance of in situ stair nosings is thus often a matter of expert judgement, where expert judgements can be used to determine that a building solution complies with the performance requirements. Table 3 of Standards Australia Handbook 197, An introductory guide to the slip resistance of pedestrian surface materials, recommends a minimum of class X or class R10 products for accessible dry internal stair nosings where handrails are present and class W or class B or 30
4 Total rise Nosing Tread Going Riser Total going Landing Overhang tread. Standards Australia HB 50 defines a nosing as semicircular or rounded projecting part of a window board, stair tread, or other member. The nosing has also been defined as the part of the tread that overlaps the tread below, although BS defines a nosing as the projecting front edge of a tread or landing that may be rounded, chamfered or otherwise shaped. Templer defined a nosing as the front and usually rounded edge to a stair tread. It frequently projects over the riser below it. This is probably the best definition of those reported, as it allows for edges that do not project and recognises that some edges may not be rounded. Stairways should ideally be free of any sharp edges, as these are more likely to cause serious injury than rounded edges in the event of a fall. class R11 products for accessible wet internal stair nosings where handrails are present. It also recommends a minimum of class X or class R10 products for dry internal ramps with slopes greater than 2 o, and class V or class R11 products for external ramps. Section 4 of HB 197 is titled Which wet slip test should I use as the basis for my specification? With the benefit of hindsight, I would suggest the pendulum test, since it can be used at any stage of the tiles lifecycle to determine the available slip resistance. We know that some products lose a considerable amount of their slip resistance shortly after laying, such that any ex-factory test data can be illusory. All ramp classifications are based on ex-factory test data. The slip resistance of products changes over time due to wear and as a function of maintenance, not just in terms of frequency, but also due to the type of cleaning products and cleaning equipment. Wet barefoot ramp classifications are particularly appropriate for wet barefoot areas. Oil wet ramp classifications are particularly appropriate for industrial and commercial locations, where frequent contamination of the floor is to be expected, such that it is almost certain that employers mandate the wearing of suitably slip-resistant footwear. While the pendulum test can be used for safety audits in such areas, it should be the test of choice in most public areas (where water may be the most likely contaminant) when there is virtually no control over the footwear that is worn. Stairways often connect areas where dissimilar activities occur. In terms of slip-resistance design they represent a transition zone. Furthermore, it should be recognised that different cleaning methods are used on stairways, as many cleaning machines cannot be used. This may influence the forensic analysis of stairway falls. Accessible stairways and nosings Nosings serve a dual purpose on steps: they provide a firm slipresistant leading edge of the step and visually highlight the step edge against the tread and riser surface. The selection of appropriate nosings is integral to maximising safety and visual clarity of a stair flight. Where stairways are required to be accessible, the BCA requires that they be constructed in accordance with AS , which requires stairways to have a strip, not less than 50 mm and not greater than 75 mm, on the tread at the nosing with a minimum luminance contrast of 30 per cent to the background. This is essentially a colour contrast requirement. AS 1657 states that The nosing should be such that the edge of the stairs is highlighted, especially where the stairs may be used in a variety of lighting conditions. The AS luminance contrast requirement for nosings presumes that every tread has a nosing. The ADA/ABA advises Consider providing visual contrast on tread nosings, or at the leading edges of treads without nosings, so that stair treads are more visible for people with low vision. Neither the BCA, nor AS , define a nosing. The NZBC defines a nosing as the rounded projecting edge of a stair NZBC accessible stairs must have colour contrasting bull nose tiles with a rounded leading edge having a radius of 5 to 10 mm (previously 10 to 15 mm). The ADA/ABA and the ANSI A117.1 standard imposes a maximum 13 mm radius of curvature. Ideally, each step should have a nosing that is integral with the step and contrasts visually with the finish on the stairs to identify the edge of the step. The nosing should preferably wrap around the edge of the step, covering about 55 mm of both the tread and the riser. This will protect the edge of each step from becoming worn, and will provide a visual contrast looking up as well as down the stair flight. Proprietary nosings should be flush with the rest of the tread and must be securely fixed, so that they do not present a trip hazard. They should be inspected regularly for any movement or loose fixings. The likelihood of a slip occurring on a stair tread is, in part, affected by the proportion of the foot that can be placed on the stair tread. The new and in-service slip resistance of the stair tread and nosing will also affect the likelihood of a slip. The British Building Research Establishment (BRE) has advised that where anti-slip tape is applied to tread edges, it should be installed on the very edge of the tread where the nosing shape is square. Where the nosing is rounded, the slip resistant material must continue to the vertical face. ASTM Committee F13 may advise that The surface of stair treads for new construction shall have treads or nosings, or both, that are abrasive, textured, and slip resistant for a minimum of 25 mm as measured from the leading edge of the nosing. The nosing shape will also determine how much of a shoe will overhang a step, especially where there is a short going. Where the going is less than 300 mm, the material and design of the nosing contributes to the risk of a slip. The risk of overstepping a nosing is also a function of the stair geometry. The higher the riser is, the more the toe is pointed downwards on descent. An increase in the riser height tends to be equivalent to a shortening of the going. As the going decreases, it becomes harder to place a substantial portion of the foot on the step, increasing the risk of an overstep in descent. This risk increases as the number of descents increases. The risk of slipping increases if the tread surface and nosing are finished in a smooth material, if the steps are wet, or if the nosing shape is rounded. Going size variability between steps also increases the risk of an overstep. Applying proprietary nosings may reduce the risk of slipping for some combinations of risk factors. Poor lighting and lack of nosing contrast also increase the likelihood of oversteps. Whatever disturbs our gait increases the risk of a misstep, a loss of balance, or a fall. Gait on a stair is not an autonomic or mechanical activity that takes place without deliberate and sometimes conscious interaction with the mind. Obviously the mind controls our gait. Hurrying and slow gait can cause stair falls, as can not paying attention, distraction, carrying things and misjudging the location of a nosing. 32
5 Handrails Handrails might be defined as a graspable, secure, continuous and unobstructed handhold provided to users on stairs, steps, ramps, and other surfaces serving to provide a visual cue to changes in elevation, aide in stability, and aide in recovery from a slip, trip, or stumble. Handrails are most effective when people use them before they lose their balance. Once balance has been lost, any protective effect depends on the accuracy of arm movements and the speed of reaching for the handrail. Handrails are used in different ways on ascent and descent of stairways. The usage may vary from minimal (an occasional touch) to extensive. Generally in descent, the hand is slid down the rail in a continuous motion to give the user a sense of security and for some greater postural stability. People with disabilities, older people, and others benefit from continuous gripping surfaces that permit users to reach the fingers outward or downward to grasp the handrail, particularly as the user senses a loss of equilibrium or begins to fall. Handrails provide a necessary safety function. Someone who uses the handrail has a fair but not certain chance of aborting a fall and avoiding injury. The chances are only fair because the magnitude of the fall forces may be greater than one s ability to maintain one s grip, the body s attitude during the accident may render it impossible for one to maintain a grip without the twisting motion s damaging one s wrist, or one s reaction time after the onset of the balance loss may be too slow to permit one to tighten one s grasp in time. AS requires The fastenings and the materials and construction of handrails shall be able to withstand forces, in accordance with AS Properly constructed rails can aid stair users to avoid losing balance on stairs. They may also be the only means by which a user may recover after losing balance, thereby avoiding a fall. Handrails must be useable. The BCA details where they must be provided and the range of acceptable heights for handrails and balustrades, as well as other aspects of their construction. Circular handrails should not rotate within their fittings. Handrails must be at a consistent height above walking surfaces, stair nosings, and ramp surfaces. While they must be located along at least one side of a ramp or flight, stairways are safer when they have handrails on both sides. Handrails required to assist people with disabilities must be provided in accordance with AS , which should be regarded as demonstrating best practice. AS requires handrails of 30 to 50 mm diameter circular cross-section, which allows an adult to have a power grip where the thumb and index finger can encircle the rail. The shape of a handrail affects the force that can be exerted by the user s hand. If the hand cannot easily conform to the shape of the handrail or if the shape and the size do not provide sufficient finger purchase on the rail, the user s hand may not be able to generate sufficient stabilizing force. Some common traditional profiles afford users a poor power grip. While this circular shape requirement may be too limiting in choice in private situations, there are a number of non-circular cross-sections that are also quite graspable. Handrails shall be constructed and fixed so that there is no obstruction to the passage of a hand along the rail. The clearance between a handrail and an adjacent wall must be at least 50 mm. Exposed edges and corners must have a radius of at least 5 mm (so that there are no sharp edges). Movement on stairs is characterised by a repeating action of acceleration and deceleration. To maintain a safe and comfortable gait, Continued page 116 MOVEMENT JOINT SOLUTIONS FOR INDUSTRIAL / COMMERCIAL / RESIDENTIAL The Original Neoprene-X-Pansion Loc Strips, Tile Strips & Expansion Joint Covers Latham Terrazzo, Stone & Tile Control Strips Latham Type CA-25V Floor Joint Cover Contact Latham Australia for full product details Phone: Fax:
6 Continued from page 34 Where ramps serve as accessible ramps under Part D3 of the BCA, they must be in accordance with AS Ramps with the maximum gradient of 1 in 14 must have landings at 9 metre intervals. Ramps with the minimum gradient of 1 in 20 must have landings at 15 metre intervals. Walkways with a gradient of 1 in 33 must have landings at 25 metre intervals. Kerb ramps and step ramps may have a maximum gradient of 1 in 8. The gradient of walkways between landings shall be constant. The gradient of ramps between landings shall be constant. Accessways, walkways, ramps and landings shall be constructed with no lip or step at joints between abutting surfaces. However, a construction tolerance of up to 5 mm is acceptable using rounded or bevelled edges. Image courtesy of Terrazzo Australian Marble the whole motion has to be continuous and rhythmical. To walk very fast on steps is nearly as difficult as to walk very slowly, which is a challenge to our ability to stand on one leg for any length of time. This is why young children whose legs are too small to manage a rhythmic gait on stairs made for adults, and elderly or disabled people with stiff joints, struggle to maintain their balance on stairs. This is also why the handrail is not just a safety device for them but a crutch. The optimum height of a handrail for any given individual is a function of their body dimensions and how closely they are walking next to it. Handrails should be accessible within 75 cm of all portions of stair width. Handrails should extend beyond the stairway (by the length of a tread) so that the user can maintain a hold whilst taking the last step to the floor, unless this encroaches into required circulation spaces. Handrail extensions are not required for continuous handrails at the inside turn of switchback stairs and ramps. The ends of handrails shall be returned away to a side wall, or turned downwards through an angle of 180 in order to reduce the severity of any unintended impact. Pedestrians with visual impairments use the handrails to determine where the stairway terminates. Handrails are necessary for safe negotiation of stairways and ramps especially in the stressful conditions of an emergency. A lack of handrails increases the risk of falling as the user cannot stabilise himself or herself whilst negotiating the stairs. Ramps Visually impaired pedestrians similarly rely upon the slope of handrails being parallel to the slope of ramps. It is thus important that tile fixers ensure that the tiles are properly set out to ensure that the junctions between the ramps and platforms are properly located. Many ramps provide access to facilities for persons with disabilities, particularly those in wheelchairs. As such, the specific requirements of AS must be followed with respect to the slope of ramps and walkways with a gradient of 1 in 33 or more, the maximum distance between landings, the dimensions of circulation spaces (particularly at doorways), the maximum camber and crossfall of ramps (1 in 40), the angles of approach of surfaces with different gradients, the need for kerbs, the need for tactile ground surface indicators, and the construction of handrails. AS , details exactly where tactile ground surface indicators must be positioned. It should be recognised that while the details that are provided in AS for kerb ramps are most appropriate for environments with level surfaces, they may be inappropriate for steeply sloping terrain, such that an alternative design solution will be required. Clause of AS advises that When measured with a straightedge, the finished surface of the tiling should be flat and true to within a tolerance of ±4 mm in 2 metre from the required plane. The lippage between two adjacent tiles should not exceed 2 mm. In the case of tiles where the surface has been ground flat, for example polished tiles, the lippage should not exceed 1.5 mm, and for joint widths of 3.0 mm or less the lippage should not exceed 1.0 mm. It also notes that Lippage is inherent in all installation methods and may also be unavoidable due to the tile tolerances. It should be noted that AS recommends a minimum joint width of 3 mm for floor tiling in order to allow for differential movements. Fixing tiles on stairs AS :2007 does not provide any guidance on the fixing of tiles to stairs. Before tiling a stairway, contractors should measure the substrate geometry. If the stairway has non-uniform dimensions, or the steps have a significant slope, the set-out may be quite complex. Tile fixers must carefully measure the dimensions of the substrate as they may have to overcome an inconsistent geometry. Any defects in the substrate should be reported in writing to the building owner, builder or architect, as is appropriate. Should the tile fixer fail to recognise the deficiencies in the layout of the area to be tiled, he may bear some legal responsibility for any non-compliant faults that he perpetuates. The latest guidance from the UK (in the public comment draft of BS , Wall and floor tiling: Design and installation of ceramic and mosaic tiling in special conditions) is that Treads should be laid on a rigid base. If the treads are to be set on metal trays these should have a similar stiffness to the tile. The steel supporting tread should be designed to limit deflection to span/720. Treads should be fully bedded on either semi-dry sand:cement mortar or an adhesive. If semi-dry sand:cement bed is used, it should be a minimum of 25 mm thick and should be fully bonded. When designing stone stairs, the risers should be seated on top of the treads and secured in place with stainless steel fixings. Risers should be set against mortar giving sufficient restraint to guard against breakage from impact damage. The Tile Council of North America 2007 Handbook for Ceramic Tile Installation has separate recommendations and drawings for concrete, metal and wooden stairs in method S On concrete stairs, the concrete should be finished with a medium-rough bush-hammer finish and be free of cracks, waxy or oily films, and curing compounds. On metal stairs, reinforcing mesh is mandatory and should be attached to the metal by tack welds or other means. The metal stair riser may also be tiled, although this will require that the mortar bed and the reinforcing be cut at the junction of the tread and the riser. Wooden stairs require the use of a waterproof membrane for exterior and wet area installations; and a cleavage membrane is required for interiors. Flexible sealant should be installed beneath the riser where it overlies the tread. 116
7 The Terrazzo, Tile and Marble Association of Canada Tile Installation Manual provides guidance and drawings for five stair tiling systems, including the use of prefabricated steel pans. Organic (dispersion) adhesives are not acceptable for these applications. A minimum of 95 per cent adhesive contact coverage is generally required on exterior surfaces and wet areas, and a minimum of 80 per cent for interiors. To minimise the potential for cracking, a sealant or prefabricated movement joint must be installed between the junction of the riser and the tread. However, coved bases and coved movement profiles can also be used at this juncture. When selecting finishes, consideration should be given the potential wetting of internal stairways due to fire sprinklers under emergency egress situations. Stair treads and landings subject to wet conditions should be designed to prevent the accumulation of water. The use of cove tiles facilitates maintenance. Tiles that are used on external stairs in cold climates must be frost resistant. Unsupported ceramic tile nosings cannot be cantilevered over the riser. The use of prefabricated stair nosings or carborundum inserts may provide additional slip resistance, but should not be allowed to project more than 5 mm above the tread surface or to substantially impede the drainage of surface water. When the tiling is finished, the stair riser height should deviate by no more than 10 mm over the entire flight, with no deviation between adjacent risers exceeding 5 mm. The stair tread depth should deviate by no more than 10 mm over the entire flight, with no deviation between adjacent goings exceeding 5 mm. Penetrations Surprisingly, none of the cited foreign installation publications deals with penetrations through waterproof membranes. The BCA requires that balustrades or other barriers be provided along the sides of stairways, ramps, balconies and the like, if the side is not bounded by a wall, and its level above the surface beneath is more than 1 metre. Given that these barriers must be of sufficient strength and rigidity to withstand the foreseeable impact of people, they must be firmly mounted. In many instances the tiling being penetrated will have been waterproofed. Clause E2.8 Penetrations, of AS , states Where pipes, rails or anchoring penetrate a waterproof membrane they will need to be appropriately detailed. Where tiling has been installed and it is subsequently necessary to penetrate a waterproof membrane, the membrane should be reinstated so that the waterproofing is not compromised. It is often necessary to place handrails and grabrails in bathrooms. AS requires that The fastenings and the materials and construction of grabrails shall be able to withstand a force of 1100 N applied at any position and in any direction, without showing any visible signs of deformation or loosening of the fastenings. This requires that wall framing should be appropriately reinforced, perhaps with 12 mm structural plywood before fixing finished wall sheets. Since grabrails are sometimes installed as a temporary measure to assist the elderly in showers and on steps, provision for future fixing should be made when considering the adaptability needs of new buildings in order to provide housing for life. Appropriate provision must also be made for restitution where membranes will be breached, for example, in showers or on balconies. Some guidance is provided in AS , Waterproofing of wet areas within residential buildings, and in the guides prepared by the Master Builders Association Waterproofing Council (NSW) Technical Committee. The 2004 Guide to External Wet Area Waterproofing (External Balcony Decks) is available for viewing at au/default.asp?id=178&parent=64#. A new draft of this very useful guide advises that the design, location, method of detailing should be Image courtesy of King Marble, Victoria. carefully considered prior to membrane installation. Balustrade penetrations are a potential weak point in any membrane system, so wherever possible, should be kept to a minimum. Where balustrades are attached to a structure, the following key principals should be adopted: The preferred method of attaching a balustrade is to face fix the balusters to the outside face of the structure, thereby not penetrating the membrane. If fixing through the membrane the preferred method of fixing is to place the baluster in a core hole. If possible, avoid the use of base plate fixings. The membrane system should be bonded onto the balustrade post and terminate 25mm above the finished floor level. If the balustrade post is hollow, it should be either completely sealed to prevent water entry. Alternatively, if water can enter the hollow section, it should drain out of the hollow section above the finished height of the membrane. If a base plate is unavoidable, the membrane should be continuous under the base plate. The fixings for the base plate should be countersunk. The base plate should be over-flashed by a second layer of membrane terminating 25 mm above the finished floor level. Where the membrane terminates 25 mm above the above the finished floor level then it should be concealed with a cover plate. The cover plate will protect the membrane from mechanical and UV damage. The cover plate will also improve the appearance of the finished baluster. The diagrams below, which have been taken from the new draft, feature optional soluble salt gutters to minimise efflorescent staining of facades. There is also a short chapter on Efflorescence control through balcony design. Balconies need falls where the fall in floor tiles should tiletoday.com.au issue
8 118 be at least 1 in 80, to ensure the run-off of surface water. The drainage system might also incorporate drip edges, storm water drainage outlets and grated drains (particularly where such drains are required to provide access for mobility impaired persons. Since balconies often lead to stairways, appropriate thought should also be given to the provision of water stops in order to prevent efflorescence on risers and treads. The Building Commission Guide to Standards & Tolerances 2007 (www. buildingcommission.com.au/resources/documents/s+t_guide_07.pdf) states (in clause 13.08) that Calcification or efflorescence caused by water coming from a deck or balcony that occurs on walls below or beside the deck or balcony; or that appears in the mortar joints of the deck or balcony tiling, is a defect. In conclusion Although the BCA provides some deemed-to-satisfy solutions for stairways, it does not consider all of the relevant aspects in great detail. Exits (including ramps, stair treads and handrails associated with exits) are listed as essential safety measures in Table I1.2 of Volume 1 of the BCA. As such, they must perform to a standard no less than they were originally required to achieve. Thus, the ramps and stair treads must retain sufficient slip resistance to be slip resistant. In Victoria, the Building Commission seems to expect an inspection every three months to ensure that there are no obstructions and no alterations, Notes_ pdf. Richard Bowman is chair of the Standards Australia committees on slip resistance of pedestrian surfaces; fixing of ceramic, natural and reconstituted stone tiles; ceramic tiles; and ceramic tiling adhesives. Richard is the managing director of Intertile Research Pty Ltd, and technical director of Full Frontal Tile & Stone Expo phone ; Acknowledgements: The permission to publish extracts from the MBA Waterproofing Council s forthcoming Guide to External Wet Area Waterproofing (External Balcony Decks) is gratefully acknowledged. advertisers index COMPANY page # READERLINK # (for free product information enter the readerlink # on the card provided) Amber Australia 23, , 614 Ardex Australia 53, , 612 Artistic Stone 17, , 577 Architectural & Structural Adhesives Australian Tile Council Australian Tile Council (Victorian Division) 88, B.A.T. Trims Beaumont Tiles 60, Bisazza CDK Stone Australia Cersaie Cevisama Champion Building Materials Chengdu Zaijian ColorTile 8, 22, , 571, 582 Creative Tiling Davco Construction Materials Decoramics 22, , 632 Di Lorenzo Pty Ltd Dural/CDK Stone Australia Elios/Ocean + Merchant Eureka Tiles Australia 25, 31, , 588, 604 Everstone 29, 41, , 595, 615 Fibonacci Stone Full Frontal Tile & Stone Expo Gemart (Shanghai) Husqvarna Construction Products Aust. 71, , 613 Johnson Tiles Australia 24, , 597 Latham Australia Laticrete Legend Pacific Australia Lithofin/CDK Stone Australia Mapei Australia Marazzi S.p.a Nanokote National Ceramic Industries Australia Nuova Mondial/CDK Stone Australia Ocean + Merchant Origen Australia Phoenician Stone Prestige Tiles/R.A.K. Ceramics 23, , 600 Qualicer Renaissance Tiles 22, , 596 RLA Polymers Romax Southern Cross Ceramics 21, 23, , 575, 583 Spirit Marble & Tile Care Stoneworld Concepts Tau Ceramica The Software Magician The Stone Cutter Tile Power 2, Tile Today Trend Tile Vetrostone 22, , 622 Volare Concepts 11, 35, , 591, 607 FAX OR POST YOUR PRODUCT ENQUIRIES Listed by each advertiser s name are page numbers on which their products are featured. There is a readerlink number listed for each advertiser, simply enter the number e.g. 300, in the appropriate space on the readerlink card. Fax the enquiry card to or mail to the address on rear of card. The index is supplied as a service to our readers. No liability is created by or accepted for inadvertent errors or omissions.