Stopgap F77


STOPGAP F77 is a solvent free two part epoxy resin system which cures to provide a waterproof surface membrane. STOPGAP F77 impedes the passage of residual construction moisture and rising damp from affecting subsequent floor covering installations, therefore allowing early installation of floorcoverings in fast track building programmes.

STOPGAP F77 is pigmented black to allow the user to visually control coverage uniformity. It can be used to isolate residual construction moisture where relative humidity values are up to 98%.

It is essential that STOPGAP F77 is applied to a clean and absorbent substrate. Any surface contaminants such as surface hardeners, cement laitance etc., should be removed to produce a slightly textured surface. The surface strength of the substrate should be greater than 1.5 N/mm2 in accordance with BS 8204-6 Part 7.2. Power floated concrete should be mechanically prepared. New concrete or sand/cement screeds should be left for a minimum 7 days before surface preparation and application of the membrane.

For further guidance please refer to the F. Ball Subfloor Preparation Guide.

Rough, uneven or damaged concrete or sand/cement screeds must be smoothed/repaired with STOPGAP 1200 PRO, STOPGAP GREEN BAG/114 or STOPGAP 460EXTERIOR REPAIR. Joints between bays where continual movement of the base is not anticipated or small hollows may be filled with STOPGAP F77 mixed with clean dry sand and allowed to fully cure before applying the membrane.

Care must be taken to minimise the occurrence of pinholes in the underlayment when pre-smoothing.

It is essential that hygrometer readings in accordance with Appendix A of BS 8203(Installation of resilient floor coverings) and BS 5325 (Installation of textile floorcoverings) are taken and recorded prior to commencing the installation.

General information



Uniclass 2015

Pr_35_31_68_47 Liquid tanking resinsPrimary


M42/150 Composition block flooring

M42/20 Composition block flooring

M42/30 Concrete/ Screed substrates

M50/10 Resilient floor tiling

M50/110 Resilient floor tiling

M50/130 Carpet tiling

M50/15 Carpet tiling

M50/150 Sheeting

M50/155 PVC sheet flooring in special wet areas

M50/170 Carpeting

M50/20 Sheeting

M50/25 Carpeting

M51/110 Carpeting

Specification data - Liquid tanking resins

Product Reference

Stopgap F77

Product Options

Technical properties:

  • Colour: Black
  • Working time at 20°C: 30 minutes.
  • Cure time at 20°C: 3 hours.

Digital objects

Platform Compatible Version Certified to

Revit 2017




Download now from NBS National BIM Library

Similar products from Ball, F and Co Ltd