Description
Crommelin Exterior Grade Brushable Waterproofing Membrane is a tough, flexible synthetic rubber coating for external areas that stay wet, supplied here in a 15L pail for larger jobs. It is designed for permanent water contact, for non-exposed areas with pedestrian traffic, and for use beneath screeds and toppings. It is built to move with the structure rather than crack as the building shifts.
About the formula
A ready-to-use, water-based, synthetic rubber membrane (styrene butadiene rubber) in grey. It stays permanently flexible, bridges existing cracks up to 1.5mm and bonds to a wide range of building substrates. It is low VOC and dries quickly. Once cured it can be overcoated with screeds, renders and water-based coatings, so it suits layered waterproofing systems.
Where to use it
Indoors: not intended as an interior wet-area (under-tile) membrane. Crommelin offers separate products for that job.
Outdoors: gutters, roof gardens and terraces, podium decks and balconies, retaining walls, slab edges and fire tanks. It also suits other areas of permanent water contact and non-exposed areas under screeds and toppings.
Suitable substrates listed by the manufacturer include concrete and brick, cement render, plywood sheeting, cement sheeting, lightweight aggregate block, trafficable screeds, aluminium and steel (suitably primed).
How to use it
Surfaces must be sound, clean and completely dry, with no dust, grease, curing compounds, release agents, loose particles or efflorescence. Test moisture content before coating, ideally with an electronic moisture meter. Concrete should be cured for at least 28 days, and screeds and renders for at least 7 days. Remove high points and fill blow-holes and honeycombing with a suitable repair mortar. If the substrate is damp, prime it with Crommelin Dampstop. Treat any rust and remove loose rust material before coating metal. Stir the membrane well, then apply with a Crommelin applicator brush or roller at a surface and air temperature between 10 and 35 degrees Celsius. Recoat once touch dry, which is about 2 hours. Apply the second coat at right angles to the first. Reinforce corners, gutter damage and pin holes with Crommelin reinforcing fabric or bandage. Fit a suitable protection board over the cured membrane before any backfilling.
Important notes
Do not apply in extreme temperature or humidity. Full cure is about 7 days at 25 degrees Celsius, and coverage varies with substrate porosity. This product is intended for non-exposed pedestrian traffic, so protect the membrane from mechanical damage. Crack bridging applies to existing cracks up to 1.5mm only. Check the current manufacturer data sheet for your specific application and overcoating requirements.
Specifications
| Brand |
Crommelin |
| Product |
Exterior Grade Brushable Waterproofing Membrane |
| Pack |
15L pail |
| Colour |
Grey |
| Base |
Water-based synthetic rubber (styrene butadiene rubber) |
| Application |
Brush or roller |
| Coverage |
About 1.5m² per litre, roughly 11m² of finished coating per 15L |
| Recoat time |
About 2 hours |
| Full cure |
About 7 days at 25°C |
| Crack bridging |
Existing cracks to 1.5mm |
| Application temperature |
10°C to 35°C |
| Use |
Exterior, permanent water contact, non-exposed trafficable areas, under screeds and toppings |
Safety
Avoid contact with skin and eyes, wear suitable gloves and eye protection, and ensure good ventilation when applying. Store in a cool, dry place with the lid sealed. Wash tools in water before the membrane cures. Refer to the Safety Data Sheet (SDS) for full details.
