PlastaMasta South Coast

What is back blocking?

Back blocking is the process of reinforcing wall and ceiling joints with cut-to-size pieces of plasterboard adhered across the back of the joint with MastaBlock Back Block Cement or Cornice Cement. Back blocking helps to prevent joint cracking and peaking caused by building a movement, especially in large ceiling areas. Back blocking forms part of the plasterboard lining standard AS/NZS 2589:2007, and manufacturers' guarantees/warranties may be void if back blocking has not been carried out.

How often should I install control joints?

Control joints must be installed to relieve stresses imposed by structural movement including those due to excessive changes in temperature and humidity. In long, unbroken partitions of the wall or extensive ceiling areas, control joints should be placed not more than 12 meters in either direction, at any change in the substrate material and should be aligned with control joints in the structure.

What is glancing light?

Glancing light refers to light being cast on the face of a surface showing minute undulations. As a result of this light being cast, a shadow is produced on the other side of the undulation. This draws attention to surface texture variations such as plasterboard joints and patches, which under more diffused light would not be visible.

What type of plasterboard do I need to use for a fire rating?

Only FireShield, MultiShield, Shaft Liner, GIB X-Block and GIB Toughline can be used in fire rated systems. Please refer to the Lafarge plasterboard tech manual for wall, ceiling, column and beam encasement and ducting systems.

What type of lining should I use in wet areas such as bathrooms and laundries?

Only approved water resistant linings can be used in 'wet areas' and these include WaterShield, MultiShield, and SafeShield. Refer to the Lafarge plasterboard tech manual for installation instructions.

What substrates can plasterboard fix?

Plasterboard can fix to various substrates that form wall partitions, ceilings, bulkheads or ducting arrangements. Plasterboard is most commonly fixed to steel studs, timber studs or masonry for wall partitions. Plasterboard can be fixed to ceiling framing by either directly fixing to the joists or by first installing metal furring channel and then fixing the plasterboard to the furring channel.

What methods of fixing should I use to install plasterboard?

The Australian Standard AS/NZS 2589:2007 allows three ways to fix plasterboard to steel or timber substrates. The options are screw fix only, nail fix only, or a combination of either screw or nail with adhesive. The preferred method is to use screws or nails with adhesive. The nail fix only method is only suitable for a level 3 finish.

How do I finish a plasterboard joint once the sheet has fixed?

There are only two types of joints formed when installing plasterboard - recessed edge joints or butt joints. The recessed edge joint formed along the length of the sheets and the butt joint formed along the width of the sheet. The finishing method is the same for both types of joints, but the width of compound coverage varies.

What is the default 'level of finish' required for plastering applications?

There are three 'levels of finish' available. Level 4 is generally accepted, level of finish is for residential & commercial construction applications where flat or low sheen paints are used. Unless otherwise specified, a level 4 finish is the default finish for living areas. A level 3 finish is suitable for areas that do not require decoration, and a level 5 finish shall be used where gloss or semi-gloss paints are used or where critical lighting conditions occur on flat or low sheen paints.

What is the best way to paint plasterboard once installed?

When installed in accordance with Lafarge plasterboard installation guidelines, the finished surface of all Lafarge plasterboard accept most types of decorative finish: emulsion or oil based paints, stipples, enamels, textured coatings and wallpapers. Matt finishes give the best appearance; gloss or sheen finishes tend to highlight any surface irregularities, as will harsh or glancing light.