We use two traditional approaches to gap filling.
The first is resin gap filling, where we mix fine saw dust with resin and apply using a filling knife. This method is mainly used on parquet flooring, but can also be used on floorboards provided the gaps are not too wide.
The second method is using solid wood fillets. These are strips of reclaimed pine or other timber which are glued, wedged into place and chiselled back before final sanding for a snug fit.
Whilst it is not essential to fill the gaps between floorboards and wooden blocks, for some it is aesthetically pleasing for a sharper finish. Filling gaps can help reduce drafts and stop dust building up between cracks.