Description
Crommelin Shower Waterproofing Membrane is a ready-to-use, water-based liquid membrane for waterproofing wet areas before tiling, supplied here in a 15L pail for larger bathroom, laundry and balcony jobs. It cures to a continuous, flexible rubber-like layer with a textured surface, so cement-based tile adhesive can bond directly over the top.
About the formula
A heavy duty, modified rubber (styrene butadiene rubber) liquid membrane that is applied seamlessly, with no joins or laps, for leak-free performance. It stays permanently flexible with high elongation, so it can cope with normal movement in the substrate. It dries to a keyed finish suited to all cement-based tile adhesives that conform to AS 2358, and it complies with AS 3740 (Waterproofing of wet areas). It is a water-based product, so tools clean up with water.
Where to use it
Indoors: under tiles in showers, bathrooms, laundries, kitchens and wet rooms, on both walls and floors.
Outdoors: under-tile waterproofing on balconies. The membrane can be applied either below or above a screed.
Suitable substrates include concrete and masonry, cement renders and screeds, plasterboard and wet area gyprock, compressed fibre cement sheeting, timber, plywood sheeting and wet area particleboard, and suitably prepared steel.
How to use it
Prepare the surface first. Remove high points and protrusions, fill any blow-holes or honeycombing with a suitable repair mortar, and bring the surface back to an even profile. New concrete should have cured for at least 28 days and screeds or renders for at least 7 days. The surface must be clean, sound and completely dry. Free it from dust, grease, curing compounds, release agents and loose particles. Check moisture with a meter. If the substrate is not dry enough, prime it with Crommelin Dampstop.
The membrane is ready to use, so stir it well and apply with a brush or roller. Apply at least two coats and allow the first to dry before recoating. Complex or very irregular surfaces may need extra coats. Apply only when surface and air temperatures are between 10 and 35 degrees C and humidity is below 85%.
Tile over after the membrane has dried and cured for the recommended time. A flood test can be done after 48 hours by ponding water to a depth of 25mm for 2 hours, then removing the water straight away. Wash tools with water before the product dries. Uncured material can be removed with warm water and detergent.
Important notes
Not suitable for use over white-set plaster. Do not apply over damp substrates, and do not apply in extreme heat, cold or humidity. Allow good airflow so the membrane can cure properly. Full cure takes about 7 days. Recoat and tile-over times vary with temperature and humidity, so check the current Crommelin data sheet for your conditions. Crommelin lists companion products for detailing, including reinforcing fabric with bond breaker, Dampstop primer, polyurethane sealant and Silicone WP Plus. Always apply a trial patch if you are unsure about a substrate.
Specifications
| Brand |
Crommelin |
| Product |
Shower Waterproofing Membrane |
| Pack |
15L pail |
| Colour |
Green |
| Base |
Water-based, modified rubber (SBR) liquid applied membrane |
| Application |
Brush or roller, ready to use after stirring |
| Coverage |
About 2m2 per litre per coat, minimum 2 coats (about 15m2 of finished membrane from 15L) |
| Application temperature |
10 to 35 degrees C, maximum humidity 85% |
| Tile over |
After a minimum of 48 hours |
| Full cure |
7 days |
| Standards |
Complies with AS 3740; suitable for use with cement-based tile adhesives conforming to AS 2358 |
| Use |
Under-tile wet area waterproofing |
Safety
Even so, ensure good ventilation, avoid breathing vapours or spray, avoid skin and eye contact, and wear gloves and eye protection. Remove splashes from skin promptly. Keep the container sealed when not in use, store it cool and dry, and protect it from freezing and extreme temperatures. Keep out of reach of children. Refer to the Safety Data Sheet (SDS) for full details.
