Evening all, looking for a bit of advice regarding sealing up linear gaps. We have a building at the moment that was built in 2014 and we discovered last week that the linear gaps have not been sealed, most have 30-40mm gaps behind the architrave. Whilst the original architects try to find the original specs for the building I'm trying to find out if any regs documented any guidance on linear gaps. I know we have 8214:2016, and have found that one of the main updates in this was to include guidance on linear gaps. What I'm trying to figure out is what was recommended before this? If anyone could help it would be much appreciated.

The 2008 version of BS 8214 would have applied in 2014 and this version also stated that such gaps should of the correct dimensions and sealed with non combustible materials. https://knowledge.bsigroup.com/products/code-of-practice-for-fire-door-assemblies?version=standard