Shaun baston offers a comprehensive guide to ensure the correct centralisation of a herringbone design within a given area.

1. Centralise the room on both the length and the width by measuring the chosen focal point of the area, take measurements of the width and length of the chosen area, and divide this by two – strike a line exactly through these centre points. These lines will be known as your N/S and E/W lines (ensure central lines are as parallel as possible within the perimeter walls of the area. Where the N/S line crosses the E/W line, this must be 900).
   
2. Whenever centralising a herringbone design installation, the centre line is not the starting point of the herringbone pattern.
   
   Key point
   • The centre of an area is not the starting point of any herringbone design
   • The width of the plank/tile is the only dimension required for herringbone pattern centralisation
   
3. The centre of the herringbone design needs to be calculated – there is a mathematical equation for this but to explain how to work it out on-site will help the understanding of this equation.
   
4. Start by creating an exact square from whatever product size in use. The width of the plank is the only dimension required for herringbone centralisation (eg, 9”x3” the 3” width is the key dimension). In this instance create a 3”x3” perfect square.
   
5. Draw a line from corner to corner on 45 degree within this 3”x3” square. This line will strike through the centre of the square. Measuring this line will give you a linear size of 108mm. This is known as the cross-sectional 45-degree dimension.
   
6. Divide this 45-degree dimension by four which is a 1⁄4 of the square (=108mm / 4=27mm). This figure of 27mm is what is called the herringbone centralisation shift number. (This figure is only compatible with 3” wide planks but at any length.)
   
7. The shift size of 27mm is key to centralisation of any 3” wide plank when installed as a herringbone design. Referring to step one, measure 27mm from the N/S centre line at two points along this line. Mark a second line through these 27mm shift marks ensuring it is exactly parallel with the centre line. There will now be two lines down the length of the area, one is the centre of the area and the other is the centre of the herringbone design. This 27mm shift line will ensure that there are equal cuts at both finish points of the chosen central focal point.
   
   Key point
   • 27mm is the shift centralisation key line based when installing any 3” wide product
   • Ensure the 5×5 jig piece is taped together firmly and perfectly aligned to create a perpendicular template
   
8. Create a jig from the product to be used, use 10 pieces, five left and five right side. Ensure it is exactly aligned and perfectly perpendicular and 90 degrees. Always ensure that it is right plank over left when it comes to installing the herringbone design. Fully tape this together with low tack masking tape – there needs to be no movement able to occur when moving the template around.
   
   Key point
   Always ensure it is right plank over left when installing a herringbone design
   
9. Place the tip of the newly created jig piece on the 27mm shift line where this line meets the E/W central line. Where the bottom two planks of the jig piece coincide then also place this point on the 27mm shift line. The herringbone design is now centralised perfectly within the chosen area. Draw around this jig piece and apply Karndean universal adhesive within these lines. (Never over glue the lines.)
   
10. Install the herringbone blocks up the length of the room N/S line and never across the width E/W. Repeat this process by going up and down the area until cuttings are required.
    
    Key point
    Always ensure herringbone is installed up the length row by row and never across the width
    
    Summary
    We now know how to work the centralisation shift number for a herringbone pattern installation. Any 3” wide plank has a central shift line of 27mm – this was a 3” square measured diagonally from corner to corner then divide this figure by four.
    This will give you your central figure – 3”x3” square, 45-degree diagonal size 108mm divided by 4 = 27mm.
    
    Now understanding the way to work out the central shift line we can work any plank/tile width central shift line for a herringbone installation. Top tip – always remember no. 9!
    
    Herringbone design centre equation
    All the sums and figures required to centralise any plank width when installed as a herringbone design…
    
    We now know the process which enables us to work out the central shift line for any width plank. 3”x3” square, 45 degrees from corner to corner = 108mm divided by four = 27mm shift line (always to the right).
    
    If we work out the 45 diagonal cross section of a 1” square then from there we can use a mathematical equation – this will enable us to simply carry out a sum and this will give us a central shift line. This prevents the need for creating squares and measuring from point to point.
    
    If a 3” wide plank has a diagonal size of 108mm then a 1” square would be the total of 108/3 = 36mm. We have divided the diagonal size of the 3”x3” square 108mm by 3, this gives us our 1” diagonal line size (36mm).
    
    So a 25mm x 25mm (1”) square would have a diagonal size of 36mm, therefore a 50mmx50mm would have a diagonal size of 72mm. Every inch increment is an increase of 36mm.
    
    Now this just gives us our diagonal size which then needs to be divided by four. Remember our 3” square was 108mm diagonally which we divided by four to give us a shift line of 27mm.
    
    • The equation is as follows to work out the shift size if using a one inch wide product:
    3”x3” rotated @ 45 degrees = 108mm (TIP – TIP) / 4 = 27mm / 3 = 9mm
    • To explain we have worked out what the shift line required is to centre a herringbone design using only a one inch wide product. The shift line is 9mm (to the right of the centre room line). If a 1” wide product has a central shift of 9mm then a 2” product would have a shift of 18mm, then a 3” wide product would be as we know 27mm. This works in increments of 9mm per every inch increase on width of product.
    • The number 9 is all you need to remember when centring a herringbone design in any given area. A simple equatNINEion is required to formulate the dimension. Whatever width product you have then times it by…
    3”x9 = 27mm, 4”x9 = 36mm, 6”x9 = 54mm
    
    This is the simple sum to work out the size required to centralise any width product to any given area when installing in a herringbone format.