Waterproofing in Porirua

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 common trap is a 'free survey' that always diagnoses rising damp and sells a chemical damp-proof course, when the real cause is condensation, a leaking gutter or bridged damp course. Get an independent, qualified diagnosis before paying for injected chemicals.

Damp proofing resists moisture and rising damp (like a damp-proof course in a wall); waterproofing resists liquid water under pressure, as in a basement below the water table. Below-ground and wet-area work needs true waterproofing, not just a damp treatment.

A bathroom or wet area typically runs NZD 750-3,800, membrane and below-ground systems NZD 3,800-14,000, and full structural waterproofing NZD 7,500-28,000.