Start with the roof, not the product
Every roof we survey tells us something different: the age and type of the existing layer, how water ponds, where drains sit, how much equipment stands on the slab and how often people walk across it. The right system follows from those facts. Choosing a product first and fitting the roof to it is the most common reason a new waterproofing layer fails early.
Bituminous membranes
Torch-applied or hot-applied bitumen membranes remain a reliable choice for new slabs and for roofs that will receive protection screed or tiles. They are tough, tolerate foot traffic during construction, and have a long track record. Their weak points are laps and terminations: every overlap and upstand has to be heated, pressed and checked. Exposed membranes also need a UV-resistant finish in our climate.
Liquid-applied PU and acrylic coatings
Liquid systems form a seamless layer that follows complicated roofs with many penetrations, AC plinths and cable trays. They are often the practical choice for refurbishing an occupied building, because they can be applied over a prepared existing surface without heavy removal. Performance depends on dry-film thickness, so we measure it during application rather than estimating it from the number of coats.
PU spray foam with protective coating
Where heat gain matters, sprayed closed-cell polyurethane foam adds insulation and waterproofing in one layer. It must always be protected with a compatible UV-resistant coating, and applied by trained crews using proper plural-component equipment.
What we recommend asking for
Whatever the system, ask your contractor for the approved data sheets, a method statement, an inspection and test plan, and a flood or water test where it is practical. These documents are how you know the roof was built the way it was specified.