Description
Crommelin Exterior Grade Brushable Waterproofer is a grey, synthetic rubber based liquid membrane for areas that stay wet, including permanent immersion, protected pedestrian areas and surfaces that will be covered by a screed or topping. This 1L pail suits small repairs and compact jobs. It dries to a tough, flexible film that moves with the structure underneath.
About the formula
A water based, ready-to-use membrane built on synthetic rubber (styrene butadiene rubber). The manufacturer describes it as low VOC and fast drying, with good adhesion to a wide range of building surfaces. It stays flexible after curing so it can follow structural movement, and it can bridge existing cracks up to 1.5mm. It is suitable for permanent water immersion and, per the manufacturer's technical data sheet, for collecting and storing potable water. Once cured it can be overcoated with screeds, renders and water based coatings.
Where to use it
Indoors: not intended as an interior wet-area (under-tile) membrane. Crommelin makes 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 non-exposed pedestrian areas and applications under screeds and toppings.
Suitable surfaces listed by the manufacturer include concrete, brickwork, concrete blocks, cement render, screeds, fibre cement sheeting, plywood sheeting and steel (suitably prepared or primed). The technical data sheet also lists aluminium and lightweight aggregate block.
How to use it
Surfaces must be clean, dry and sound, and free of dust, grease, curing compounds, release agents, loose particles, efflorescence and laitance. Concrete should have cured for at least 28 days, and screeds and renders for at least 7 days. The manufacturer calls for a moisture test to confirm the substrate is dry enough to coat, and recommends an electronic moisture meter. Remove high points, fill blow-holes and honeycombing with a suitable repair mortar, and make good any defects. Masonry should be flush pointed.
The product is ready to use, so stir it well before applying. Apply with a brush or roller. Use a bond-breaking sealant in all joints, junctions, protrusions, angles and internal corners, and apply the membrane to the positive side of the substrate. Apply two coats at the recommended rate, running the second coat at right angles to the first once the first is touch dry (about 2 hours). Apply only between 10°C and 35°C and in humidity no higher than 85%. Wash tools with water before the product dries.
Important notes
Allow a minimum of 72 hours before backfilling and about 7 days for full cure. Ensure good airflow while curing, and do not expose the membrane to moisture until it has fully cured. Protect the membrane from damage, and install suitable protection board before any backfilling. Do not apply in extreme weather or humidity. If the substrate is not dry, the manufacturer advises priming with Crommelin Dampstop, so check the full instructions on the Crommelin website for your substrate. Avoid applying the membrane too thickly in corners, as this can reduce flexibility. This listing is for the brushable (pail) product, not the sprayable aerosol version.
Specifications
| Brand |
Crommelin |
| Product |
Exterior Grade Brushable Waterproofer (Exterior Grade Waterproofing) |
| Model number |
1081-001 |
| Pack |
1L pail |
| Colour |
Grey |
| Base |
Water based, synthetic rubber (styrene butadiene rubber) membrane |
| Application |
Brush or roller, 2 coats |
| Coverage |
About 1.5m² per litre per coat, so about 0.75m² of finished two-coat membrane per 1L |
| Crack bridging |
Existing cracks up to 1.5mm |
| Recoat time |
About 2 hours |
| Backfill |
Minimum 72 hours |
| Full cure |
7 days |
| Application conditions |
10°C to 35°C, humidity up to 85% |
| Clean up |
Water, before the product dries |
| Use |
Exterior, permanent immersion, non-exposed pedestrian areas, under screeds and toppings |
Safety
It is stable under normal storage and use, and is incompatible with strong oxidising agents, strong acids and strong bases. Avoid contact with skin and eyes, wash tools and any spills with water while the product is wet, and store in a cool, dry place with the lid sealed. Refer to the Safety Data Sheet (SDS) for full details.
