Waterproofing is an essential functional part of any building. While it isn’t a visible feature, it’s inherently important to retain the integrity of a structure. Hard-to-see places, around or under basements, swimming pools or tiled terrace areas are equally as important to protect with accredited waterproofing systems as the main areas of the building structure. Internal areas are no exception and also require protection, especially in wet areas such as bathrooms and laundries, with approved waterproofing systems such as membranes and floor coatings

What is spray-on waterproofing used for?

Spray-on waterproofing systems are beneficial for many situations as they generally provide a seamless coating and therefore minimise any opportunity for failure over time. If any damage does occur, spray-on solutions have the added advantage of being able to be touched up easily to repair the damaged areas. When used for roofing, many spray-on coating systems can be applied directly over existing roofing materials, reducing costs associated with the removal of in situ roofing.

What is membrane waterproofing?

There are various options available for membrane waterproofing, the most common of which is known as TPO, or thermoplastic polyolefin. Many membrane waterproofing systems are ‘torch-on’ solutions comprised of bitumen products. In New Zealand, there are a range of certified torch-on membrane systems designed for different areas of the country and suitable for area-specific climatic conditions. Generally, membrane waterproofing systems are installed on flat or low-pitched roofs and have a high level of stability and UV resistance.

What are the options for below-ground waterproofing?

Underground tanking is often inaccessible for repairs - or extremely costly to access - after it is installed. For this reason, the right tanking solution can have a higher initial cost as maintenance over time is often not feasible. Tanking is generally required for below-ground structures such as foundations, slabs and basement areas and is most commonly used in a membrane form which is applied over the entire surface of the underground structure to prevent the ingress of water. Tanking products are also available in liquid form, applied as a coating to the structures requiring waterproofing. The right solution for your project will depend on various factors including the site and environmental factors such as flooding risks.

Deck and terrace waterproofing

Decks and terraces are a vital area and one overrepresented in waterproofing issues in residential properties in New Zealand. While low-level open-slatted decks don’t generally cause waterproofing issues because they are designed to allow water to drain between the decking planks, it is those situated at higher levels that pose the biggest risks, as well as those that are solid in form and do not have the gaps between planks of traditional timber decking.

Decks that consist of a solid material with a waterproofing material laid over it have been known to cause watertightness issues because they can collect large amounts of water that requires the ability to drain. Many decks of this style are installed above habitable areas of a house and therefore have the capacity to cause leaking directly into interior areas. For these reasons, it is extremely important to understand the requirements around deck and terrace waterproofing systems and ensure the right solution is specified.

Waterproofing for external decking or terrace areas is similar in nature to the systems used for low-slope or flat roofing and commonly includes the use of thermoplastic polyolefin (TPO), torch-on bitumen membrane PVC and asphalt products. Liquid-applied products are also an option for decking and terraces and are commonly acrylic or polyurethane.

Internal waterproofing

Whether it’s an internal pool, shower or bathroom, every wet area inside the house requires waterproofing. Many internal waterproofing products come in liquid form, and are applied during the building process, although can be retrofitted during a renovation or upgrade. In tiled areas, sheet waterproofing is often used to create a waterproof barrier, while liquid systems are also specified for bathrooms and other internal wet areas. Paint-on waterproofing is another option. This type of agent is generally applied similar to paint and is rolled onto the wall or floor surface requiring waterproofing and acts as an additional protection, beneath a membrane solution.