Waterproofing in New South Wales

It depends on the method and area. Internal sealants and damp-proofing for a small area are the cheapest option; cavity-drain membranes and tanking cost more; a full basement or below-ground waterproofing system is the most expensive, running into five figures. The cause of the water dictates the right system.

Small sealant jobs on a minor damp patch are DIY-able, but below-ground waterproofing against groundwater pressure is specialist work — get it wrong and you trap water or flood the space. Full basement systems should be designed and installed by a qualified specialist.

Yes — reputable structural waterproofing comes with an insurance-backed guarantee so the cover survives if the contractor ceases trading. Ask whether the guarantee is company-backed or independently insured, because a company-only warranty is worth little if they close.

A properly installed cavity-drain or tanking system can last decades, and quality membranes carry long guarantees. Cheap surface coatings applied over an unaddressed water problem fail fast. Longevity depends on correct diagnosis and installation far more than the product.

Wet areas need a waterproof membrane behind tiles on floors and walls, correctly detailed at junctions and drains. In many countries this is regulated work with a standard to meet — a failed shower membrane is one of the most common and costly building defects.

A bathroom or wet area typically runs AUD 800-4,000, membrane and below-ground systems AUD 4,000-15,000, and full structural waterproofing AUD 8,000-30,000.