Oakum is a rope made of flax fibres drenched in pine tar (or Stockholm tar) and makes for a terrific caulking method to seal joints or fill gaps in timber. These fibres are driven into the wedge-shaped seam between planks or in large holes. The caulking is then covered over with linseed oil putty. Originally this was used in the shipping industry to fill crack between timber boards. Our Oakum can be easily torn into smaller pieces to suit your application.