Fasteners are to be positioned between 10 and 16mm from sheet edges, with the appropriate number of intermediate fasteners (if required), as specified in the appropriate installation details, equally spaced across the sheet into the support member. Sheets are to be held firmly against frame while fasteners are positioned.

Wherever possible commence fastening from the centre portion of the sheet, proceeding to the ends and edges. Alternatively, start at one edge and work across the sheet to the other edge.

Fasteners are to be driven home with the head slightly below the surface of the sheet, but not punched through the face linerboard. Care should be taken to avoid damaging the face or core of the plasterboard.

Combination Adhesives/Fastener Fixing

Combination adhesive/fastener fixing is generally the preferred system except in fire rated installations, tiled wet areas, or over existing linings or vapour barriers.

When used in accordance with the following instructions the adhesive/fastener method of fixing produces a system that is comparable in strength to a fully nailed or screwed wall or ceiling. This method also reduces the number of fasteners required and minimises the possibility of nail pops due to frame movement.

Gyprock Acrylic Stud Adhesive has good gap filling properties and will bridge board and studs which are slightly out of alignment.

When temporary fasteners are used, they should remain in place for a minimum 24 hours, or longer in slow drying conditions.

When fixing plasterboard to garage ceilings, or to prepainted ceiling battens (eg. Colorbond), or to timber with CCA or LOSP treatment, adopt the 1/3 spacing fastener and adhesive installation method.

Cautionary Notes:

• To reduce the possibility of fasteners popping, permanent fasteners should not be closer than 200mm from the edge of adhesive daubs.

• Contact surfaces of framing must be free of oil, grease or other foreign materials.

• The final bond of Gyprock Stud Adhesive may be unsatisfactory if: Used on wet timber. Used with Category B timber. Temporary blocks/fasteners are removed too early.

The use of fastener only fixing systems should be restricted to applications where adhesive cannot be used, such as in fire rated installations, tiled wet areas and over existing linings or vapour barrier.

• Sheets are to be held firmly against frame while driving appropriate Gyprock screws.

• Screws are to be driven at 400mm maximum centres on walls and 300mm maximum centres on ceilings and must be spaced equally across the sheet. Outer screws are to be placed 10 to 16mm from sheet edges.

• Screw fix butt joints on framing members at 200mm maximum centres with screws opposite each other.

• Screw fix internal and external corners at 300mm maximum centres with screws opposite each other.

• For a cornice finish, screw fix ends of ceiling sheets at a maximum 300mm centres.

• For a set finish, screw fix ends of ceiling sheets at a maximum 200mm centres.

• When fixing to resilient furring (N581), ensure screws do not contact supporting joists.

The Gyprock Plasterboard Control Joint Part NP35 is designed to form expansion or control joints in Gyprock plasterboard walls and ceilings. The control joint is located between the sheets and set over. When the compound is dry, the filament tape is removed leaving a clean, well-formed joint.

Door frames extending from floor to ceiling constitute control joints. For doors less than ceiling height, control joints extending from both corners of the frame to ceiling may be used.

Control joints are to be installed:

• In long partition or wall runs, at no more than 12m centres.

• To coincide with control joints in the supporting frame. The continuity of Gyprock plasterboard and support framework should be broken at control joints.

• In continuous ceiling areas, spaced at no more than 12m centres in both directions. Control joints may be positioned to intersect light fixtures, heating vents and air diffusers.

• Between floor levels, eg, in stairwells.

• Allow a 15mm maximum gap between ends of Gyprock plasterboard sheets.

• Locate control joint, Rondo NP35, centrally in gap. Fasten flanges and Gyprock plasterboard sheets to frame at a maximum of 300mm centres.

• Set over bead as for normal joint application using centre channel ribs as screeding guides.

• Finish the joint in the normal manner.

• When the joint is dry, remove the filament tape.

• Back-Blocking Joints.

Back-blocking is a reinforcing system where pieces of Gyprock plasterboard are laminated to the back of the sheets, behind joints.

Where mid-span butt or end joints are not required but are used to minimise plasterboard wastage, these joints must also be back-blocked. All mid-span joints must be positioned within 50mm of the mid-span point between the framing members.

Fix back-blocks with Gyprock BASE COAT or Gyprock CORNICE CEMENT applied with a notched spreader to form beads 6mm x 6mm at approximately 20mm centres over the entire face of the back-block.