Waterproofing glossary

The pressure exerted by standing water against a structure, increasing with depth below the water level..

The level below ground at which the soil is saturated with water.

Waterproofing applied to the dry face of a structure — the inside of a basement wall — rather than the face the water arrives from..

Waterproofing applied to the face water arrives from — the external side of a basement wall or the top of a slab..

A continuous barrier wrapping an entire below-grade structure — beneath the raft, up every retaining wall and sealed above ground level — so the structure effectively sits inside a sealed box..

A PVC strip or swellable hydrophilic profile cast into a construction joint to block water travelling along it.

Pumping groundwater away from an excavation or structure to keep the working area dry through construction or repair..

Land created by filling in water bodies, marsh or foreshore.

A spray-applied elastomeric coating produced by reacting two components at high temperature and pressure.

A family of resin systems used as liquid-applied waterproofing coatings, injection resins and sealants, ranging from rigid to highly elastomeric..

A two-part thermosetting resin that cures rigid, with high strength, excellent adhesion to dry concrete and good chemical resistance..

The chemical breakdown of a coating by alkali, in which the binder reacts with alkaline salts in fresh cementitious substrates and loses cohesion..

A primer formulated to resist the high alkalinity of fresh cement render and provide a stable base for a topcoat..

A high-build flexible coating with substantial elongation, able to stretch and bridge hairline cracks as a substrate moves..

A water-based coating with good UV stability and colour retention, widely used as an exterior decorative and protective finish..

A penetrating water repellent that lines the pores of masonry and concrete without filling them, leaving the surface visually unchanged..

A coating with high resistance to carbon dioxide diffusion, applied to concrete to slow the advance of the carbonation front while still allowing water vapour out..

The weak, fine layer of cement and fines that rises to the surface of concrete as it cures and bleed water evaporates.

An unplanned joint formed when fresh concrete is placed against concrete that has already begun to set, so the two do not knit together..

Voids in hardened concrete where mortar failed to fill the spaces between coarse aggregate, usually from inadequate compaction or congested reinforcement..

Keeping cementitious material adequately moist and at a suitable temperature while it hydrates and develops strength and impermeability..

Fine cracking caused by cementitious material contracting as it loses moisture, either while still plastic or over the following weeks..

The slow reaction of atmospheric carbon dioxide with the alkaline compounds in concrete, which lowers its pH.

Corrosion of reinforcement driven by chloride ions penetrating the concrete, typically from sea air, sea spray or brackish groundwater.

White crystalline deposits left on a surface when water moving through masonry or concrete evaporates and leaves dissolved salts behind..

Concrete breaking away from a structural member, pushed off from behind by corrosion products forming on the reinforcement.

New corrosion that begins immediately around a concrete repair patch.

Ground moisture drawn upward through the pores of masonry by capillary action, typically producing a horizontal tide mark and salt deposits..

Damage caused when salts dissolved in moisture crystallise within the pores of masonry or plaster, exerting pressure as they grow..

A traditional mortar using lime rather than cement as the binder, setting slowly by carbonation and remaining softer and more vapour-permeable than cement mortar..

Repair of historic buildings using materials and techniques compatible with the original fabric, favouring breathable, reversible interventions..

A viscous petroleum-derived binder, the base material of most sheet waterproofing membranes and of traditional built-up roofing..

A permeable fabric used in construction to separate, filter, protect or drain.

A moulded void-forming panel laid over a waterproofing membrane beneath soil or paving, creating a continuous drainage path to outlets..

A sacrificial board or screed laid over a completed waterproofing membrane to shield it from mechanical damage by following trades or backfill..

The movement of liquid through narrow spaces against gravity, driven by surface tension.

The ability of a material to let water vapour pass through it while still resisting liquid water..

Expansion and contraction of building materials as temperature changes.

Carbon fibre fabric bonded to a structural member with epoxy resin, adding tensile and confinement capacity with almost no added weight or section..

Increasing the size of a structural member by adding reinforcement and concrete around the existing section..

A non-destructive test that measures the electrical potential between the reinforcement and a reference electrode on the surface, mapping where corrosion is active across a member or elevation..

An instrument that locates reinforcement and measures the depth of concrete cover over it, without breaking out..

The thickness of a coating after it has cured, measured with a gauge across a grid of points..

The thickness of a coating measured immediately after application with a comb gauge, before any solvent or water has evaporated..

A test that passes an electrical charge over a coated surface to locate pinholes, voids and discontinuities — 'holidays' — that are invisible to the eye..

A test in which a dolly is bonded to the coating and pulled off under measured force, recording both the load and where the failure occurred..

Plugging the outlets, flooding a completed waterproofed area and holding the water — typically 48 to 72 hours — while the space below is observed for any sign of ingress..