Wet Areas Using Plasterboard

INSTALLATION 168 DEFINITIONS 168 WET AREA REQUIREMENTS 168 WATERPROOFING REQUIREMENTS BY AREA 169 GENERAL REQUIREMENTS 171 FRAMING 171 PLASTERBOARD LAYOUT 171 PLASTERBOARD FIXING 171 CONSTRUCTION DETAILS 173 Wet Areas Using Plasterboard Australian Standard AS 3740 - Waterproofing of Wet Areas within Residential Buildings defines a wet area as an area within a building supplied with water from a water supply system and includes bathrooms, showers, laundries and sanitary compartments. Waterproofing of wet areas may be achieved by systems using water resistant s such as WaterShield or TruRock. This section contains: Installation instructions for wet area walls. Waterproofing treatment methods for WaterShield and TruRock walls. Construction details for wet areas. Some elements of wet area installation will be carried out by a plasterer, and other elements will be completed by trades such as plumbers and tilers. All waterproofing must be carried out by an approved applicator [Refer to 2.3 for more information on wet areas]. 167

3.1.4 WET AREAS USING PLASTERBOARD Installation Definitions and Wet Area Requirements Definitions WATERPROOF MEMBRANE s are a layer of material impervious to water that are usually liquid applied. They must comply with AS/NZS 4858:2004, Wet Area Membranes and be applied according to the manufacturer s instructions. FLASHING Flashing is a strip or sleeve of impervious material such as metal angle, or a liquid applied product such as a waterproof membrane. It must provide a barrier to moisture movement. SHOWER AREA Shower areas consist of enclosed and unenclosed areas: Unenclosed shower areas extend 1500mm horizontally from the shower connection on the wall, up to a height of 1800mm from the finished floor. Enclosed shower areas are bounded by walls or screens up to a height of 1800mm from the finished floor. Walls or screens include hinged or sliding doors that control the spread of water to within the enclosure A shower fitted with a frameless glass shower screen or screen over a bath less than 1500mm long is not an enclosed shower. Wet Area Requirements Different wet areas require different levels of treatment to protect them from moisture. WET AREA INSTALLATION REQUIREMENTS Area Level of Risk Walls Junctions Penetrations + Shower area High Water Resistant Waterproof Waterproof Bathrooms Medium Waterproof^ Areas adjacent to baths and spas Medium Water Resistant Waterproof Waterproof * Walls adjoining other vessels Low Water Resistant Waterproof Waterproof * Laundries and WCs Low Waterproof^ Bathrooms and laundries requiring a floor waste High Waterproof^ Waterproof + Including mechanical fixings or fasteners. ^ Applies to wall/floor junctions only. * Horizontal surface waterproof, vertical surface water resistant. to 150mm high behind tiles WaterShield or TruRock FIGURE 1 Basin 168 Technical Advice 1300 724 505 knaufmetal.com.au

WET AREAS USING PLASTERBOARD Waterproofing Requirements 3.1.4 Installation Waterproofing Requirements by Area Water Resistant Walls Use WaterShield or TruRock covered with a waterproof membrane and tiles. For all joints, corners and fastener heads use MastaBase or MastaLongset. [Refer to waterproof membrane manufacturer for application instructions] Walls Adjoining Other Vessels Ensure walls within 75mm of a vessel such as a sink, basin or laundry tub are water resistant to a height of 150mm minimum above the vessel. Seal all edges where the vessel is fixed to the wall. Waterproof Penetrations Use a waterproof sealant or a proprietary flange system to waterproof penetrations. Waterproof Vertical Junctions (where required) Use a waterproof membrane as vertical flashing that has a minimum overlap of 40mm to the wall sheeting for each leg. Wall/Floor Junctions in Shower Areas and Adjacent to Baths and Spas Use a waterproof membrane on walls to: 150mm minimum above the finished shower floor level or lip of bath And 25mm minimum above the maximum retained water level And with the horizontal leg width a minimum of 50mm. Wall/Floor Junctions Outside Shower Areas Use a waterproof membrane or metal angle as flashing with a vertical leg a minimum of 25mm above the finished floor level with the horizontal leg width a minimum of 50mm. WaterShield or TruRock to 150mm high behind tiles to walls of bath as flashing 25mm min. above finished floor level Tiles FIGURE 2 Bath (without shower) installation on timber flooring Technical Advice 1300 724 505 knauf.com.au 169

3.1.4 WET AREAS USING PLASTERBOARD Installation Waterproofing Requirements Finishing or all-purpose compounds are only permitted outside of tiled areas WaterShield or TruRock Use only MastaBase or MastaLongset in shower area to 1800mm high Tiles as flashing with horizontal leg width of 50mm and 25mm above finished floor level 1500mm min from shower outlet. Timber floors in wet areas must be completely covered with a waterproof membrane. FIGURE 3 Internal in situ tray for unenclosed shower on concrete or compressed fibre cement floor Finishing or all-purpose compounds are only permitted outside of tiled areas Use only MastaBase or MastaLongset in shower area to 1800mm high WaterShield or TruRock Optional reinforcing angle behind as flashing 25mm min. above finished floor level External shower tray (installed before wall lining) Tiles FIGURE 4 External tray for enclosed shower on timber flooring 170 Technical Advice 1300 724 505 knaufmetal.com.au

WET AREAS USING PLASTERBOARD General Requirements, Framing, Plasterboard Layout and Fixing 3.1.4 Installation General Requirements For WaterShield [Refer to 3.1.1 non-fire rated requirements] For TruRock [Refer to 3.1.1 fire rated requirements] Waterproof all cut edges of WaterShield or TruRock that may be affected by moisture, including all penetrations and the bottom edge over a preformed shower base. Only use paper tape and MastaBase or MastaLongset for jointing in tiled areas to strengthen the joint and provide a continuous surface for the waterproof membrane. Recess pre-formed shower bases, baths and spas sufficiently into the wall to allow the tiles to pass down the inside perimeter rebate of the shower base [Refer to Construction Details] After the installation of tiles, apply a waterproof sealant to all wall/floor junctions and vertical corner joints. Masonry adhesive and stud adhesive are not permitted in tiled areas. Frame movement should be limited at junctions in high risk areas such as showers. For this purpose use a min. 35 x 35 x 0.7mm BMT metal angle fixed to the frame in internal corners. Framing For internal steel walls [Refer to 3.1.1]. Masonry walls lined with tiles on WaterShield or TruRock must use the furring channel method. For masonry walls with [Refer to 3.1.3] Plasterboard Layout For WaterShield [Refer to 3.1.1 non-fire rated requirements] For TruRock [Refer to 3.1.1 fire rated requirements] Plasterboard Fixing Use the Fastener Only Method in tiled or fire rated areas. Masonry or stud adhesives are not permitted. Drive fasteners to just below the sheet surface, taking care not to break the paper linerboard. Laminating screws can be used to fix butt joints in the second and third layer. Tiles weighing up to 22 kg/m² (porcelain 9mm thick) may be installed when fasteners are spaced at imum centres. Tiles weighing from 22 to 32 kg/m² may be installed when fasteners are spaced at imum centres on studs at 450mm centres, or fasteners spaced at 100mm centres on studs at 600mm maximum centres. Technical Advice 1300 724 505 knauf.com.au 171

3.1.4 WET AREAS USING PLASTERBOARD Installation Plasterboard Fixing FIGURE 55 WaterShield in in Tiled Tiled Areas Areas 1 Layer 1 Layer Horizontal - Horizontal Screw Screw Only Only Method Method Butt Joints Fix at centres. Stagger by 300mm min on adjoining sheets and on opposite sides of the wall Plasterboard must not be fixed to to head track Sealant If If required, use sealant to to maintain Fix on on each stud 60 -- 100mm Field 200mm min Recessed Edges Fix on each stud 10-50mm Sheet Edges Fix screws 10 -- 50mm from sheet edges except at head and base tracks Corners Openings vertical screw spacing Tile Weights Tiles weighting up to 22 kg/m 2 (porcelain 9mm thick) use, screws at imum centres when studs are at 600mm centres Tiles weighing from 22 to 32 kg/m 2 use, screws at imum centres when studs are at 450mm centres, or screws at 100mm maximum centres when studs are at 600mm centres. Fix on each stud 50mm FIGURE FIGURE 66 WaterShield WaterShield in in Untiled Untiled Areas Areas 1 Layer 1 Layer Horizontal - Horizontal Screw Screw and and Adhesive Adhesive Method Method Butt Joints Stagger by 600mm min on adjoining sheets and an opposite sides of the wall Plasterboard must not be fixed to head track Sealant If required, use sealant to maintain Fix on each stud 60-100mm 300mm max 200mm min Recessed Edges Fix on each stud 10-50mm Butt Joints Float between framing for Level 4 and Level 5 finishes Temporary holding block, if required Sheet Edges Fix screws 10-50mm from sheet edges except at head and base tracks 300mm max Corners 300mm max Openings 300mm max vertical screw spacing Adhesive daubs 200mm min from screw points and edges Fix on each stud 50mm Field Adhesive daubs 25mm diameter, 15mm high and 300mm max spacing Sheet Width Fixing Pattern 900mm S A A A S 1200mm S A A A A S 1350mm S A A A A A S 172 Technical Advice 1300 724 505 knaufmetal.com.au

WET AREAS USING PLASTERBOARD Construction Details 3.1.4 Details NON-FIRE RATED SHOWER NON-FIRE WALL RATED DETAILS SHOWER WALL DETAILS Bond breaker Sealant, if required to maintain Sealant, if required to maintain FIGURE 7 Shower Base Class 2 membrane shown - FIGURE 8 Shower Base Class 3 membrane shown - 2 layers of Knauf Watershield used to prevent recessing pre-formed shower base into stud work Furring channel Additional horizontal furring channel along shower base Sealant, if required to maintain FIGURE 9 Shower Base Pre-formed shower tray - 6mm gap and flexible wet FIGURE 10 Shower Base over Masonry Wall Class 3 membrane shown - Optional vertical reinforcing angle in shower area Refer to proprietry waterproof membrane manufacturer for specific application instructions. FIGURE 11 Shower Corner Plan Technical Advice 1300 724 505 knauf.com.au 173

3.1.4 WET AREAS USING PLASTERBOARD Details Construction Details NON-FIRE RATED BATH DETAILS BATH DETAILS Fix angle to stud at Fix 100mm angle to max stud centres at 100mm and max 50mm centres max and from ends 50mm max from ends sheet Fix 50mm bottom from Knauf WaterShield Knauf WaterShield (compatible Tiles and tile with adhesive waterproof (compatible membrane) with area Flexible sealant wet Steel stud frame to Steel support stud frame bath to support bath Notch stud 35mm max and insert Notch minimum stud 35mm 50x25, max and 1.15mm insert minimum BMT top 50x25, hat 1.15mm BMT top hat 400mm long 35x35, Bathtub 0.7mm 400mm BMT long steel 35x35, Bathtub angle 0.7mm for BMT stud steel support angle for stud support area Flexible sealant wet Waterproof membrane Waterproof membrane NON-FIRE RATED clearance to Sealant, if required to Sealant, maintain if required acoustic to maintain integrity GENERAL WET AREA DETAILS GENERAL WET AREA DETAILS FIGURE 12 Bathtub FIGURE 12 Bathtub Refer to proprietry waterproof membrane Refer to proprietry manufacturer waterproof for specific membrane application manufacturer instructions. for specific application instructions. (compatible Tiles and tile with adhesive waterproof (compatible membrane) with area Flexible sealant wet Waterproof membrane Waterproof membrane Sealant, if required to Sealant, maintain if required acoustic to maintain integrity FIGURE 13 Wall Base in General Wet Area FIGURE 13 Wall Base in General Wet Area Outside shower Class membrane shown Outside shower - Class 3 membrane shown 174 Technical Advice 1300 724 505 knaufmetal.com.au

WET AREAS USING PLASTERBOARD Construction Details 3.1.4 Details FIRE RATED SHOWER WALL DETAILS SHOWER WALL DETAILS Knauf fire rated and moisture resistant Knauf fire rated and moisture resistant Knauf fire rated Knauf fire rated Bond breaker Bond breaker Knauf Bindex Fire and Acoustic Sealant required to maintain integrity Knauf Bindex Fire and Acoustic Sealant required to maintain integrity FIGURE 14 Shower Base Class 2 membrane shown - FIGURE 15 Shower Base Class 2 membrane shown - Knauf fire rated and moisture resistant Knauf Watershield Knauf fire rated and moisture resistant Knauf Watershield Knauf fire rated Knauf fire rated Support framing for bath Knauf Bindex Fire and Acoustic Sealant required to maintain integrity FIGURE 16 Shower Base Pre-formed shower tray with upstand FIGURE 17 Bathtub Knauf Bindex Fire and Acoustic Sealant required to maintain integrity Refer to proprietry waterproof membrane manufacturer for specific application instructions. For fire rated penetration details, refer to 3.1.1 Technical Advice 1300 724 505 knauf.com.au 175