Board and Batten Spacing: How to Calculate Even Gaps

Key takeaway: To calculate board and batten spacing, subtract the total width of all battens from your wall width, then divide the remaining space by the number of gaps. For most walls, aim for gaps that are 2-3 times the batten width.

Board and batten panelling uses vertical strips (battens) fixed to a flat surface (the board) at regular intervals. The visual effect depends almost entirely on two things: the width of each batten and the size of the gap between them.

The basic formula is simple. Take your total wall width, subtract the space taken up by all the battens, then divide what remains by the number of gaps. If you have a 2400 mm wall, 18 mm battens, and you want 7 battens (creating 6 gaps between them, plus one gap on each side), you subtract 7 x 18 = 126 mm from 2400 mm, leaving 2274 mm. Divide that by 8 gaps (6 between battens plus 2 at the edges) and each gap is about 284 mm.

You can also work with battens that sit flush against each wall edge, which removes the two side gaps and changes the calculation slightly. Both approaches are common, so it comes down to the look you prefer.

The most common batten widths for board and batten panelling in the UK are:

• 9 mm MDF strips - a slim, modern look that works well on smaller walls
• 12 mm MDF strips - probably the most popular choice for DIY board and batten
• 18 mm MDF strips - gives a chunkier, more traditional appearance
• 25 mm or wider - used for a bold, statement look or in larger rooms

Wider battens generally look better on bigger walls. A 9 mm batten can feel lost on a 4-metre wall, while 25 mm battens might overwhelm a small alcove. A useful rule of thumb: aim for gaps that are roughly 12 to 20 times the batten width. So for a 12 mm batten, gaps of 150-240 mm tend to look balanced. This is a starting point rather than a strict rule.

The relationship between gap width and batten width drives the overall feel of the design. Here are the common ratios and what they create:

• Gap roughly equal to batten width (1:1) - a tight, rhythmic pattern that feels quite traditional
• Gap 2-3x the batten width - the most popular balance for modern board and batten; enough space for the battens to stand out without crowding
• Gap 4x+ the batten width - a minimal, airy look with widely spaced battens

There is no single correct ratio. It depends on the room, the wall size, and what you find pleasing. The best approach is to try a few options visually before committing. You can use the free planner tool to experiment with different spacings on your exact wall dimensions and see what looks right.

Real walls are rarely perfectly square. Before cutting anything, measure your wall width at the top, middle, and bottom. If the measurements differ, use the largest one for your spacing calculation. This ensures your battens fit everywhere, and you can scribe or trim individual battens to follow any slight bowing.

For internal corners, you have two options: butt the battens directly into the corner, or leave a small gap (5-10 mm) that gets filled with caulk. The caulk approach is more forgiving if the corner is not perfectly straight.

External corners are trickier. The cleanest finish is to mitre the battens at 45 degrees where they meet, but this requires precise cuts. A simpler alternative is to use an L-shaped trim piece that covers the join.

Here is a quick method you can follow with a calculator or pen and paper:

1. Measure your wall width in millimetres
2. Decide on your batten width (e.g. 12 mm)
3. Choose how many battens you want (start with wall width / 300 as a rough guide for the number of gaps, then adjust)
4. Decide whether battens go right to the wall edges or whether you want gaps at the sides
5. Calculate: (wall width - (number of battens x batten width)) / number of gaps = gap width
6. Check whether the gap width looks good relative to the batten width
7. Adjust the number of battens up or down and recalculate until the proportions feel right

If the maths feels tedious, the Wall Panel Planner does this automatically. Enter your wall dimensions and batten count, and it shows you the layout to scale so you can adjust until it looks right.

A few things that trip people up with board and batten spacing:

• Not accounting for skirting boards and coving. If your battens stop at the skirting board rather than going behind it, measure the wall height from the top of the skirting to where you want the panelling to end.
• Forgetting the batten thickness in the total. It is easy to divide the wall width by the number of gaps and forget that the battens themselves take up space.
• Trying to make every gap identical by eye. Even small errors compound across a wide wall. Always mark out your positions with a tape measure or laser level rather than spacing by eye.
• Not doing a dry run. Before gluing anything, hold the battens in position (or tape them temporarily) and step back. Spacing that looks great on paper can feel different in the room.