|Plasterboard Type and Thickness||Walls (mm)||Ceilings (mm)|
For ceiling areas of intermittent high humidity e.g bathrooms and external ceilings
|SoundShield10mm and 13mm||600||600||450|
|WaterShield 10mm and 13mm||600||600||450|
|FireShield 13mm and 16mm||600||600||450|
|TruRock 13mm and 16mm||600||600||450|
|TruRock HD 13mm||600||600||450|
When installed in accordance with Knauf installation guidelines, the finished surface of all Knauf plasterboard accepts most types of decorative finish: emulsion or oil based paints, stipples, enamels, textured coatings and wall papers. Matt finishes give the best appearance; gloss or sheen finishes tend to highlight any surface irregularities, as will harsh or glancing light. In order to obtain the best finish to the walls, Knauf recommends the following:
Lay down the nap of any scuffed areas using MastaFinish, MastaLite or MastaGlide jointing compounds. The surface should be free of dust and other foreign matter.
Ensure that the joint treatment is thoroughly dry before applying the sealer.
Always seal over jointed and unjointed areas. Use roller application for paint. Overworking of sealant coat on jointed areas may cause paint to lift. Roller application applies uniform texture over the entire surface.
Use only the best quality paints and other finishes. Use of sealers or undercoats that are water based is preferred to reduce the possibility of raising the paper linerboard nap.
Lightly sand between coats if nap is raised. Apply finishes in strict accordance with manufacturers' instructions.
- To help reduce sound transmission through a wall - install an improved sound resistant plasterboard and wall system. Refer to the Knauf Technical Manual.
- Ensure no gaps or penetrations remain for sound to leak through in a wall by using a sealant. Doorways dramatically decrease the acoustic performance of the room. Even with the door closed, sound can still either flow under the door or still penetrate through the door if the door is of low acoustic performance. Solid core doors are recommended.
- Sound will travel into ceilings, through floors and be transmitted to other rooms and areas external to the house.
- Including insulation in the wall cavity between the studs will reduce sound transmission between rooms.
- Resilient mounts or channels can be installed to reduce the level of sound penetrating through the structure.
- Double separated stud walls help to reduce the level of sound penetration through a wall, by helping to de-couple the sound transmission from room to room.
Glancing light refers to light being cast along 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. The best way to overcome the effects of glancing light is to consider the following factors which will help to achieve the appearance of flatness:
- Natural and artificial lighting
- Paint effects and paint sheen
- Texture and porosity
- ‘Level of Finish’
For more information of the cause, effect and remedial measures refer to Knauf’s technical newsletter 'OnBoard Glancing Light' and also the industry publication FWCIANZ Glancing Light.