F Ball - Stopgap F77 High Performance Waterproof Surface Membrane

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F Ball - Stopgap F77
  • Available for Next Day Delivery
  • FREE Delivery when you spend over £125

F Ball - Stopgap F77 High Performance Waterproof Surface Membrane

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 floorcovering 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%.

STOPGAP F77 can be applied direct over underfloor heating screeds using a coverage of 1.8m²/kg where readings are up to 90% RH.

Technical Information:

  • Appearance: 7kg kit
  • Colour: Black
  • Working Time: 30 minutes at an ambient temperature of 20°C
  • Cure Time: Approximately 3 hours at an ambient temperature of 20°C
  • Available in: 14kg and 7kg capacity



The resin and hardener are supplied in the correct quantities for mixing without measuring. 

Applications up to 98% RH – 1.8m²/kg
Applications with underfloor heating up to 90% RH - 1.8m²/kg
Applications up to 85% RH – 2.5m²/kg

Note: The coverage rate refers to a smooth, clean surface. A textured or highly absorbent surface profile will reduce the coverage rate.

For any areas under question please consult the F Ball Technical team.

Working Time:

Once mixed and poured on to the floor STOPGAP F77 will remain workable for approximately 30 minutes at 20°C. If mixed and left in the container, the working time of STOPGAP F77 will be significantly reduced.

Curing Time:

This greatly depends on temperature, approximately 3 hours @ 20°C, making sure the surface is fully cured and tack-free before proceeding to apply the primer and underlayment.


1.5mm x 5mm trowel (included) or A2 trowel and paint roller. Use F. Ball STYCCOWIPES to remove uncured material from tools and equipment


Store between 5ºC and 30ºC.

Shelf Life:

18 months in unopened containers stored under good conditions

Delivery Information

We aim to dispatch all orders within 2 working day of receipt. Occasionally public holidays, weekends, weather events, or extremely busy periods may result in extended delivery times. In these circumstances, we will endeavour to communicate with you about the delay and resolve and resulting issues.

Please note that we do not make delivery date promises, however:

- Orders placed before 1pm on a weekday will be processed the same day.

- Orders placed after 1pm on a weekday will be processed the following morning. 

- Orders placed after 1pm on Thursday will be processed and dispatched the following day and out for delivery the following Monday (if Next Day Delivery is selected).

- Orders placed after 1pm on Fridays will be processed and dispatched on the following Monday.

For more information about our Shipping & Delivery services click HERE


UK Mainland Delivery Options:


Free Delivery: Applicable for orders of £125 excl. VAT and above
(Monday – Friday, excluding public holidays)


Collect From Store: 41 Markfield Road, London N15 4QA
(Monday – Friday, 9am–5pm excluding public holidays)


Standard Delivery: 3-5 Working Days
(Monday – Friday, excluding public holidays)


Express Delivery: Next Working Day
(Monday – Friday, excluding public holidays)

Out Of Zone Delivery Surcharges:

Isle of Wight

£12.50 per item (3-5 Working Days)

Isles of Scilly

£12.50 per item (3-5 Working Days)

Northern Ireland

£25.00 per item (3-5 Working Days)

Western Isles

£25.00 per item (3-5 Working Days)

Shetland Isles

£30.00 per item (3-5 Working Days)


£30.00 per item (3-5 Working Days)

Isle Of Man

£30.00 per item (3-5 Working Days)

Channel Islands

£30.00 per item

Republic of Ireland

Not Available


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