Black Jack Bitumen Trowel Mastic is a trowel applied black heavily filled bituminous compound with added fibres for re-enforcement, used primarily for patching holes in roofs and bituminous coatings. The product forms a surface skin, but the mass below remains soft to allow for moderate movement.

Suitable for sealing and filling holes in mastic asphalt, roofing felt, corrugated iron, metal guttering and downpipes.
Fast drying.
Remains flexible for long periods after application.