As a leading manufacturer of premium building materials, Knauf is also committed to ensuring its products enable the industry to achieve the highest levels of install quality and workplace health and safety.
This extends to technical support, training and information development to enable contractors to finish projects with peace of mind and minimise risk.
When it comes to ceiling installation, particularly in the residential market, collapses or failures arise from time to time, reminding the industry of the importance of adhering to manufacturer installation guidelines and Australian Standards.
When installed correctly, building industry professionals can avoid issues relating to ceiling system failure. While every project is different, and the most suitable fixing method can vary, the most common causes of ceiling failure include the use of non-compliant (short) screws; inadequate application of stud adhesive; no fixing of temporary blocks to the plasterboard and framing while the stud adhesive cures; lack of roof sarking to protect against water ingress and weight overload on ceilings such as air-conditioning units, ceiling fans installed without adequate engineered framing support.
“Plasterboard is one of the most common dry lining materials regularly used for ceilings in modern building construction,” commented Thanh Huynh, Knauf Engineering Services Director. “These ceilings are secured in place with both adhesive and screws fixed into the ceiling joists. Back blocks are used to reinforce plasterboard joints to reduce the risk of cracks. A complete ceiling system solution approach provides the plasterboard contractor installation confidence.”
Ceiling materials and insulation must comply with the standards set by the Building Code of Australia (BCA) including safety, health, amenity and sustainability. Of course, ceiling boards must also be used for their intended purpose. Wall boards are designed differently and don’t carry the loads a ceiling does.
Ceiling installation methods are designed to provide all parties, including installers, homeowners and occupants, with complete confidence in the integrity and longevity of the installation. While it is the homeowner’s responsibility to manage the maintenance of the home following completion of a build, responsibility lies with the builder and/or installer to deliver a best practice approach to every build.
Internal ceilings
Ceiling support options:
There are two general support options for ceiling linings:
- Direct fixed, where sheets are fixed directly to structural ceiling members (timber or steel). If plasterboard is direct fixed to structural ceiling members, trimmers are to be installed by the builder where primary ceiling support members such as girder trusses and joists change direction within a room. Trimmer spacing is not to exceed plasterboard spans
- Furred or battened fixing, where sheets are fixed to secondary framing members, such as metal or timber battens or metal furring channels installed in the opposite direction to structural members.
Direct fixed ceiling
Furred ceiling
Fixing to ceilings:
Fixing With Combination of Adhesive and Screw Fasteners
- Framing members insert (timber or steel) should be clean and free from dust, dirt, grease and surface moisture
- Refer to General Screw and Nail Fixing
- Stud adhesive daubs should be approx 25mm diameter x 15mm high
- Do not use adhesive at sheet ends
- Keep daubs 200mm (nom) from sheet edges
- Keep daubs 200mm (nom) from screw points
- At perimeter of sheet space screws at 300mm maximum centres for cornices and 150mm maximum centres for square set finish
- Full perimeter support framing should be provided in each room to fix plasterboard edges
- Take care not to slide plasterboard sheet once in contact with adhesive, to prevent thinly spread of adhesive.
Adhesive and fastener layout:
1/3 Fixing methid (preferred)
Space fasteners at 1/3 points across the width of the sheet and daubs half way between fasteners.
Conventional Methods
Use double fasteners 50-75mm apart along the sheet centreline and space daubs between the fasteners at 230mm maximum centres.
Ceiling fastener and adhesive layouts:
| Adhesive and fastener layout for ceilings | ||
| Sheet Width | Conventional fixing | 1/3 fixing |
| 900mm | FAF/FAF | FAFAF |
| 1200mm | FAAF/FAAF | FAFAFAF |
| 1350mm | FAAF/FAAF | FAFAFAF |
Legend: F= screw; F/F = double screws; A=adhesive
Fixing with screws only
- Space screws at maximum 300mm centres across the width of the sheet
- At perimeter sheet ends space screws at 300mm maximum centres for cornices and 150mm maximum centres for square set finish
- Refer to General Screw and Nail Fixing
- Full perimeter support should be provided in each room
| Sheet width | Screw points |
| 900mm | 4 |
| 1200mm | 5 |
| 1350mm | 6 |
If you want to view the full installation manual for ceiling installation visit this link
*This article was originally published here