Frequently Asked Questions

Recommendations prior to installation

  • The sheets should be delivered to a roofed and fully clad site at least 48 hours prior to installation and stored within the building close to where they are to be fixed in order to acclimatise.
  • It is preferable to lie them flat in a low traffic area for their safety with the top sheet placed upside down to keep the top sheet clean.

What framing is required?


  • studs at no more than 450mm centres.
  • where sheets join between studs, noggins should be placed no more than 600mm apart
  • where dado is used, a continuous row of nogging needs to be provided to allow the fixing of the top of the dado, bottom of the qyprock and the chair rail


  • ceiling battens must not be greater than 450mm centres

How do I fix VJ sheets to the framing?

  • Use a flexible stud or construction adhesive, and apply to all framing timbers in either a continuous bead or in “acorns” sized dollops (also prevents vibration in the walls); as a guide, approximately 1/2 tube of adhesive is used per 2.7m sheet.
  • Use 32mm finishing nails or screws that won’t rust, and fix to the studs at 600mm intervals and 300mm across the top and bottom of the sheet
  • Leave a gap approx.0.5mm between sheets to allow for structural movement and never “hammer” one sheet into the other. A 1mm gap per sheet should be left at all internal corners to allow for expansion
  • Leave a gap of approx. 10mm at the top and bottom of each sheet to prevent wicking of water up the sheet, and allow for structural movement
  • If fixing VJ sheeting over existing wall cladding, it is important to nail or screw the sheets through the cladding into the underlying framework and apply a zigzag bead of adhesive to the back of the sheet you are fixing.

Can MR VJ sheets be used in wet areas such as bathrooms, laundries, on verandah walls under a wide roof etc?

  • All brands of VJ sheets that are sold as MR or HMR have to meet the requirements of the Australian test protocol V313. The material may absorb moisture in wet area applications but this can be prevented by the following:
    • Ensuring that you leave a 10mm gap between the floor and the bottom of each sheet to prevent wicking.
    • Painting the top and bottom edges, any vertical cuts, and the back of the sheet with an acrylic latex paint before installation.
    • Painting the face of the sheets prior to using the area for the first time.
  •  Generally it is also good practice to:
    • Paint the back of ceiling sheets with acrylic sealer before installation
    • Paint the back of sheets on the inside of external walls or provide sarking where dampness may encroach.
    • Seal the face of the sheets as soon as possible after installation
    • Use a cement based wallboard to line walls that are to be tiled

Is 9mm VJ sheeting suitable for ceilings?

  • Yes, provided battens are no more than 450mm apart.
  • Screwing is recommended to allow minor adjustments to be made to sheet levels.

Can I join sheets end to end to cover only ceiling on tall walls?

It is difficult to achieve a good result when butt-joining ceiling sheets because, with expansion and contraction over time, the join will inevitably crack.

We recommend 3 options:

  1. Plan to join the sheets in a position that can be covered with a timber cover strip; e.g.: the centre-line of the room, in line with an adjoining wall, at the leading end of the hallway, etc.
  2. Design a pattern of cover strips (e.g.: a square) that can be made to look like a feature – then join sheets under these strips
  3. Use gyprock – looks great with a feature

What sort of paint should be used?

An acrylic sealer-undercoat should be applied as the base coat if purchasing or using unprimed sheets.

Do I need to prime the backs of the sheets?

  • Only if the sheets are likely to be exposed to moisture, e.g.
    • sheets on the inside of external walls where no sarking is provided
    • all sheets being used in bathrooms, laundries etc
    • ceiling sheets

Where do I start installation?

  • If sheeting both ceilings and walls, it is best to fix the ceiling sheets first.  This will then set the positions of the end walls – it looks best if the ceiling grooves line up with the wall grooves
  • If sheeting walls it is normal to start in a corner and work around the room.  However, sometimes it may be more economical to start with a part sheet (see #11)

Notes on installation

  • It is critical to ensure that the first wall sheet on each wall is perpendicular – otherwise the vertical grooves will not be parallel to windows and doorways.  The edge in the corner may need to be cut or planed to allow this.
  • Always leave a gap of approx. 10mm between the floor and the bottom of the sheet.
  • Do not put a nail or screw very close to the edge of the sheet as it may split
  • ALWAYS use a suitable dust/face mask and safety goggles when cutting sheets and make sure all dust is vacuumed up daily.

How can I minimise waste?

  1. If the wall contains doorways or windows that are more than 1210mm wide, you can sometimes save material by starting to sheet at one edge of the opening; i.e.: if you can avoid cutting a large hole out of a sheet
  2. To fill in heads above doorways and floor-length windows less than 1210mm wide, you can use off-cuts, rather than cut large holes out of a full sheet.  This is done using an off-cut and joining this to the groove of the next full sheet.  NOTE WELL: The heads must be filled in as you go, otherwise you may not end up with a gap that is a full number of ‘boards’ wide.
  3. When you have finished one wall, you can use the off-cut from the last sheet to start the next wall if practical.
  4. The VJ PLUS UNIQUE tongue can be removed by pulling from the end by using plyers if you wish to use a male offcut piece and conversely a tongue can be inserted into either side of offcut with a groove.

How do I finish internal corners?

  • Method 1: Scribe the second sheet so that it butts neatly up the existing sheet.


  • Method 2: Butt-join the corner sheets (leaving a 3-5mm expansion gap) and fit a suitable moulding (e.g. quad) to cover any run-out in the wall.


  • It is good practice to always study and measure the walls in a room before commencing the installation to minimise waste.

How do I finish external corners?

  • Method 1: Trim the first sheet off level with the outside edge of the corner stud.  Start the next sheet level with the outside edge of the trimmed sheet.  Cover the join with an external corner timber moulding.
  • Method 2: Cut the corner sheet 9mm longer than the outside edge of the stud, being careful to cater for any run-out in the vertical or bows in the stud.
    Scribe the second sheet to the line of the corner stud, again catering for any run-out in the vertical or bows in the stud.
    Using a router, form a 45deg bevel down the edge of each sheet.  (This angle will vary from 45 if the corner is not a right angle).
    Fix the corner sheet.
    Apply glue to the length of the join, and fix the second sheet.
    Allow to thoroughly dry.  Fill any gaps and sand smooth.

Safety issues

It is important to control the dust that is produced when sawing or routing MDF.

  • A Class P1 or P2 filer/respirator should be worn to prevent the inhalation of the dust.
  • Dust should be collected and removed from the work area on a regular basis.
  • Ideally, hand power tools should be fitted with dust bags.
  • Keep the work area well ventilated.

Do not burn off-cuts – they should be disposed of as land fill.

Safety glasses or goggles should be worn if dust irritates the eyes.

Please contact us to discuss your individual needs, or For Detailed Pricing