As we enter winter and the wet season (or should we say, constant living in a wet one) a reminder about tanking in wet conditions seems timely. Weather conditions can play a significant part in and can delay construction and have a lasting effect if the membrane selected requires special or unrealistic conditions during installation.

There are a number of tanking products on the market in New Zealand, bitumen, synthetic, bentonite clay etc. It is important to understand their benefits and limitations both in application and performance when specifying the waterproofing membrane on your next project.

One of the greatest benefits of the Allco Volclay range of sodium bentonite products is that it can be installed in virtually any weather conditions — including rain and snow! Volclay products can also be applied to damp substrates; there is no need to wait 28 days for the concrete to cure, saving projects precious time and money.

Another feature of the Volclay range that helps speed the installation process significantly is that priming is not required as it is on other tanking membranes. Volclay products can be installed directly onto compacted slab substrates without the need for mud slab/site concrete.

There are two types of membrane to choose from depending on the application, both types are supported by a range of accessory products.

Voltex is Allco's 'pre-applied' membrane used around formwork and on horizontal surfaces by simply laying it on the substrate. The patented carpet-like geotextile fibres of Voltex form a tough surface ensuring the active Bentonite stays in place and protecting the membrane against wet weather and construction related damage.

Swelltite is Allco's “post-applied” membrane, ideal for vertical concrete walls and block work. Swelltite is made up of 95% bentonite mixed with 5% butyl rubber, bonded to a tough geomembrane liner making it flexible and highly resilient. Swelltite has an emulsion surface on the concrete contact side making it easy to adhere to concrete walls.

Once covered by structural concrete or compacted backfill as appropriate, the active bentonite in both Voltex and Swelltite hydrates and swells in confinement, forming a dense, impervious waterproofing membrane. The swelling action of bentonite allows these products to self-heal and self-seal around penetrations and can help seal small concrete cracks caused by ground settlement or concrete shrinkage.

When it comes to tanking, there is only one chance to do it right.

Choosing the Allco Volclay range will not only minimise weather-related construction delays, it will also give your building a high quality waterproofing membrane that will protect the structure from water ingress for years to come.