The UK has a British Standard for external timber cladding, BS8605-1, in which support battens are defined as timber components of a section, grade, and durability, suitable for supporting external timber cladding. Clause 17 states that where the density of timber for support battens is required, this should be determined in accordance with EN384. This is because design of support battens might involve structural calculation, for which a characteristic density value (lower 5th percentile, with appropriate adjustments) is necessary.
A short paper, and poster presented at the 15th Annual Meeting of the Northern European Network for Wood Science and Engineering (in Lund, Sweden, October 2019) examines the effectiveness of grading by growth ring width for characteristic density, using UK and Irish grown British spruce as the case study. The grade combination “British spruce” is a mixture of Sitka spruce and Norway spruce – but is ~90% Sitka.<\/p>\n\n\n\n
You can download the conference paper<\/a> and the poster<\/a>. <\/strong><\/p>\n\n\n\n There is also some bonus content on this twitter thread<\/strong><\/p>\n\n\n\n