F.Ball Stopgap 400

F. Ball Stopgap 400 is a rapid-setting and rapid-drying cementitious repair compound designed for repairing internal floors before the application of Stopgap smoothing compounds and floorcoverings.

Its thixotropic, non-slump consistency makes it suitable for forming ramps and covings, repairing stairs and steps, and filling localised cracks, holes and damaged areas without the material slumping out of position.

Stopgap 400 is supplied as a dimensionally stable, pre-blended dry powder. The standard unfilled mix may be applied from 2–20mm, while localised repairs from 20–50mm should be completed using a filled mix containing Stopgap Graded Aggregate.

It is suitable over prepared sand/cement screeds, concrete, sound asphalt, granolithic surfaces, terrazzo, epoxy and polyurethane resins, ceramic and quarry tiles, and Stopgap waterproof surface membranes.

Under suitable conditions, the compound develops walk-on hardness in approximately 20–30 minutes and can receive Stopgap smoothing compounds or floorcoverings after approximately 1½ hours at 2mm thickness.

• Fast-setting and rapid-drying repair compound
• Thixotropic, slump-free consistency
• Suitable for light to heavy-duty internal floor repairs
• Standard unfilled application thickness from 2–20mm
• Filled application thickness from 20–50mm
• Can be trowelled to a feathered edge for localised repairs
• Suitable for repairing stairs, steps, ramps and covings
• Ideal for filling cracks, holes and damaged floor areas
• Walkable in approximately 20–30 minutes at 20°C
• Ready for smoothing compounds or floorcoverings from approximately 1½ hours at 2mm
• Dimensionally stable after application
• Protein-free for use in biologically sensitive areas
• Low-odour formulation
• EC1 Plus very low-emission rated
• Supplied in a 10kg eco-pouch

• Repairing damaged internal concrete and screed floors
• Filling localised cracks, holes and surface defects
• Repairing stairs and steps
• Forming and repairing ramps and sloping transitions
• Forming and repairing floor covings
• Localised patching before the application of smoothing compounds
• Fast-track repairs before floorcovering installation
• Repairs over sand/cement screeds and concrete
• Repairs over sound flooring-grade asphalt
• Repairs over granolithic and terrazzo surfaces
• Repairs over prepared ceramic and quarry tiles
• Application over compatible epoxy and polyurethane resin surfaces
• Application over Stopgap waterproof surface membranes

• Ensure the subfloor is sound, dry and free from contaminants that may prevent adhesion
• Concrete must be fully cured and any laitance, curing compounds or incompatible surface treatments must be removed
• Where concrete moisture exceeds 85% RH or 15g/m²/24 hours, install a suitable Stopgap moisture protection system
• Maintain the floor temperature above 10°C throughout application and drying
• Switch underfloor heating off for at least 48 hours before, during and after application
• Dampen standard absorbent surfaces with clean water before application
• Prime very absorbent surfaces with diluted Stopgap P131
• Prime non-absorbent surfaces with neat Stopgap P141 and allow the primer to dry
• For a full standard mix, add 10kg of powder to approximately 2.3L of clean water
• Alternatively, mix approximately 3–4 parts powder to 1 part clean water by volume
• Add the powder gradually while mixing until a smooth, lump-free consistency is achieved
• Mix only enough material to use within approximately 10–15 minutes at 20°C
• Do not add extra water or retemper the material after it begins to thicken
• Apply the standard unfilled mix from 2–20mm
• For localised repairs above 20mm and up to 50mm, add Stopgap Graded Aggregate at 1 part aggregate to 1 part powder by volume
• F. Ball also permits the filled mix above 6mm where improved economy is required
• For best results across larger areas, maintain a minimum thickness of approximately 2–3mm
• Apply and spread the compound using a suitable steel smoothing trowel
• A wet smoothing trowel may be used after approximately 15–20 minutes to improve the finish before the compound fully sets
• Where a smooth finish is required over a filled repair, leave the filled mix slightly below the finished level and cap it with unfilled Stopgap 400 or a suitable Stopgap smoothing compound
• At temperatures above 20°C, use clean cold water and keep the product out of direct sunlight to reduce the risk of flash setting
• Wash tools with water immediately after use
• For internal use only

For repairs up to 20mm, use the standard unfilled Stopgap 400 mix. For small localised repairs above 20mm and up to 50mm, use a filled mix containing an equal volume of Stopgap Graded Aggregate.

Although Stopgap 400 can be trowelled to a feathered edge for localised detailing, F. Ball recommends maintaining a minimum thickness of approximately 2–3mm when treating larger areas.

If the filled mix does not provide the required surface finish, apply it slightly below the finished level and complete the repair with a layer of unfilled Stopgap 400 or a suitable Stopgap smoothing compound.

Drying and setting times are based on approximately 20°C and will vary according to temperature, humidity, substrate absorbency and application thickness.

Stopgap 400 is not recommended for external applications.