There are building regulations that regulate the spacing between deck railing balusters. A 100mm wide sphere cannot pass between 2 spindles in the UK. The maximum distance between two spindles in a balustrade’s top and bottom is 99mm. This applies to both stair- and terrace balustrades. This determines how many balusters are needed for each railing section. This method will determine the spacing between rail posts and balusters for every section. However, it will not be exact. The spacing may vary depending on the section.
Building regulations govern the spacing of balusters along a deck railing.
- This determines how many balusters are needed for each railing section.
Take the distance between 2 rail posts, and measure it. Take the measurement of 1 baluster.
To calculate the allowance for balusters, add the baluster thickness to allow space between them. Ex. 5cm x 5cm (2×2 inch) Balusters are 5cm wide. Given a space maximum of 9.9cm (4inches), 5 + 9.9 = 14.9cm (5 55/64inches).
Divide the spacing between the posts by the allowance for balusters, and round the results to determine the required number. Example: The Post Spacing is 1.8m, or 180 cm (72.7 inches). 180 / 14.9 = 12.08. This gives you 13 balusters.
The baluster allowance is calculated by adding the baluster thickness to maximum space allowed between balusters.
- Divide the space between posts by the allowance for balusters, and round the result to get the total number of balusters needed.
Divide the total spacing of balusters in the following way: multiply the number by the baluster’s width. Example: 180-(13 x 5), 180-65 = 115cm (45 9/32 in).
Add 1 for space between balusters to get the total spacing. Ex: Example: 115/13+1 = 8.21cm (3 15/64inches) space between each baluster, and each rail section post or baluster.
You should plan your deck to ensure that the majority of rail sections are equal in length. You can keep the spacing of balusters the same, but let the distance between posts vary. This will create the most balanced look. However, ensure that there is not more space between balusters and posts than what’s allowed.
Before starting to build or ordering materials, be sure you check the planning requirements.