Traditional sand mastic forms the perimeter seal between many timber sash and case window frames and the surrounding masonry. When it cracks, falls away or loses adhesion, replacement may be required as part of proper window maintenance.
Why Perimeter Mastic Matters
The joint around a window frame is exposed to wind and rain. Failed perimeter material can leave gaps that look unsightly and may allow moisture or draughts into vulnerable areas around the frame.
Removing Failed Material
Replacement work involves assessing the existing joint and removing defective material as required before a suitable new perimeter finish is applied. The surrounding masonry and timber condition also need to be considered.
Part of Sash Window Maintenance
Sand mastic replacement is often carried out alongside external painting, timber repairs or glazing work. Coordinating these items can help ensure the perimeter of the window is properly maintained rather than repeatedly patching isolated defects.
Request a Quotation
Send clear photographs of the window perimeter and your location. We can advise whether the issue appears suitable for sand mastic replacement and arrange further assessment where needed.