Waterproofing & protection glossary

A round foam cord pushed into a joint before the sealant to set its depth and stop it bonding to the joint bottom, so it stretches between the two faces only.

See also Elastomeric sealant · Expansion joint

Related pages Expansion joints · Checklist: Expansion joints and joint systems

Raised bubbles in a membrane or coating, usually from moisture or air trapped beneath it that expands in the heat, or from solvent trapped in a thick coat.

See also Substrate moisture test · Recoat window

Related pages Membrane blistering · PU bubbling

Carbon dioxide from the air slowly lowers the alkalinity of concrete from the surface inwards; once the carbonated zone reaches the steel, the steel loses its natural protection and can corrode. The depth shows when phenolphthalein is sprayed on a fresh break (BS EN 14630).

Related pages Anti-carbonation · Concrete carbonation

Polymer-modified cement-based coatings applied in coats on concrete or masonry, in rigid and flexible grades. They bond to damp concrete and are used in tanks, wet areas and basements.

See also Crystalline waterproofing

Related pages Cementitious · PU vs cementitious

A scale of surface roughness after preparation — from almost smooth (light grinding) to very rough (scabbling) — defined in ICRI 310.2R with reference chips; each coating or flooring system states the profile it needs.

See also Substrate · Laitance

Related pages Checklist: Resin flooring and microcement

Where one concrete pour meets the next. It is not designed to move, but it is a common leak path below ground, so it is sealed with a waterstop, a swelling strip or an injection hose, or covered by the external waterproofing.

Not the same as Expansion joint

See also Waterstop

Related pages Construction joints

The quantity of material applied per square metre. Comparing material used with the area covered is a simple check that the specified thickness was reached; the rate itself comes from the product TDS and the approved specification.

Also called Coverage rate (معدل التغطية)

See also Wet-film thickness · Dry-film thickness · Technical data sheet

Filling a crack under pressure through packers: polyurethane resins to stop water in wet or leaking cracks, epoxy resins to re-bond dry cracks structurally — the latter on an engineer’s decision.

Related pages Crack injection · Concrete cracks · Checklist: Crack and joint injection

Cementitious materials with active chemicals that react with water and the products of cement hydration to grow insoluble crystals in the pores and fine cracks of concrete, blocking the water path. Supplied as a surface slurry or as an admixture in the mix.

See also Negative-side waterproofing · Cementitious waterproofing

Related pages Crystalline · Crystalline: admixture or coating

For cementitious materials, keeping them moist and at a suitable temperature for the specified period so they gain strength without cracking; for resins, the chemical hardening time before load, water or traffic.

See also Cementitious waterproofing

A treatment that resists moisture moving by capillary action or as vapour from damp soil, but is not designed to resist water under pressure — for example a coating on a wall that stays above the water table.

Not the same as Waterproofing · Water resistance

Related pages Waterproofing vs damp-proofing

The temperature at which water vapour in the air condenses. Coatings go on only when the surface is warmer than the dew point by the margin in the TDS; otherwise a film of moisture spoils the bond.

See also Vapour barrier · Substrate moisture test

A layer with open channels — a dimpled sheet, a drainage composite or gravel — that carries water sideways to the drains so it does not build up against the waterproofing. A filter geotextile usually keeps soil out of the channels.

Not the same as Protection layer

See also Geotextile

Related pages Protection & drainage

The thickness of a coating once cured — the value specifications usually set. Measured by gauge on steel; on concrete it is checked with samples, destructive methods, or from the wet-film thickness and the solids content.

Not the same as Wet-film thickness

See also Consumption rate

White salt deposits left on concrete or masonry when water passing through it evaporates at the surface. It is a sign of water passage, not its cause; treatment starts at the water source.

Related pages Efflorescence

A gun-applied material — polyurethane, polysulfide or silicone, for example — that cures into a rubber-like seal in a joint and moves with it within its stated movement capability.

See also Backer rod · Expansion joint

Related pages Expansion joints

A deliberate gap through the structure that lets its parts move with temperature, shrinkage and settlement. The waterproofing must bridge it with a detail that accepts the movement — never a rigid coat across it.

Also called Movement joint (فاصل الحركة)

Not the same as Construction joint

See also Elastomeric sealant · Backer rod

Related pages Expansion joints · Expansion joints · Expansion joint failure

A small sloped or rounded infill of mortar, or a preformed strip, at an internal corner such as where a roof meets a parapet, so the membrane turns the corner without bridging or being strained.

Also called Cant strip (الشطفة أو الزاوية المائلة)

See also Upstand

A metal strip (counter-flashing) fixed over the top edge of the waterproofing turned up a wall or parapet and sealed into a chase or onto the wall face, so rainwater cannot run behind the membrane and its edge stays protected from sun and damage.

See also Upstand · Termination

Related pages Roof parapet

Ponding water on a completed horizontal waterproofing — a roof, a planter, a wet area — to a set depth and for a set time, then inspecting below for leaks, before the protection layers go on. ASTM D5957 is the usual guide.

Also called Water test (اختبار التسرب بالماء)

See also Hold point

Related pages Checklist: Flood test

A thick, low-permeability polymer sheet, often HDPE, that lines ponds, lakes, channels and containment areas; its seams are welded on site and tested by air pressure or a vacuum box.

See also Geotextile

Related pages Geomembrane liners · Checklist: Geomembrane liners

A permeable fabric of synthetic fibres used to separate, filter or protect: it keeps soil out of a drainage layer, cushions a liner and keeps apart layers that must not mix.

See also Drainage layer · Separation layer

Related pages Geomembrane liners

A stage the work cannot pass until it has been inspected and released in writing — for example accepting the substrate before priming, or the flood test before the protection layers.

See also Inspection and test plan · Flood test

Related pages QA/QC checklists

A test that finds pinholes and thin spots (“holidays”) in a coating or lining: a low-voltage wet sponge or a high-voltage spark detector is passed over the surface and signals where current reaches the substrate. ASTM D4787 covers linings on concrete.

Also called Continuity test (فحص الاستمرارية)

Related pages Tank epoxy · Checklist: Tank linings

The pressure of water standing against a structure; it grows with the depth of water above the point. Below the water table, the waterproofing has to resist it at all times.

See also Waterproofing · Type A, B and C protection

Related pages Basement protection types

A project document that lists, for each activity, what is checked, how, against which criterion, by whom, and where the hold and witness points are.

See also Hold point · Method statement

Related pages QA/QC checklists

A roof where the thermal insulation — usually XPS boards, which absorb little water — lies above the waterproofing and protects it from heat, UV and traffic. In a conventional roof, the waterproofing sits on top of the insulation.

Also called Protected membrane roof (السطح المعكوس)

See also Thermal insulation · Screed to falls

Related pages Inverted roof · Roof systems compared

A weak, powdery layer of cement and fines on the surface of fresh concrete. Coatings applied over it fail with it, so it is removed by grinding, blasting or water jetting.

See also Substrate · Concrete surface profile

Related pages Epoxy peeling

The width by which one sheet overlaps the next; laps are welded or sealed and staggered between layers. The minimum width is set by the system.

Also called Overlap (الركوب)

See also Membrane

Related pages Checklist: Sheet membranes

A polyurethane applied as a liquid in coats by roller, brush or spray that cures into an elastic, seamless membrane; aromatic grades need a UV-resistant top coat where they stay exposed.

See also Top coat · Blistering

Related pages Liquid PU · PU bubbling · Why PU waterproofing fails

Waterproofing applied as a liquid by brush, roller or spray that cures into a continuous film with no laps; its performance depends on reaching the specified thickness everywhere.

See also Wet-film thickness · Dry-film thickness · Consumption rate

Related pages Liquid PU · Polyurea

The waterproofing layer itself: either factory-made sheets (bituminous, PVC, TPO, EPDM or HDPE) joined on site, or a liquid applied in coats that cures into a seamless film.

See also Liquid-applied membrane · Lap · Membrane attachment

Related pages Bituminous membranes · Liquid PU

Fully bonded (torched, glued or self-bonded, so a leak cannot travel far beneath it), loose-laid and ballasted with gravel or pavers, or mechanically fixed at the laps to resist wind uplift.

See also Membrane · Lap

A document submitted before the work that describes how an activity will be carried out: sequence, materials, equipment, checks and safety measures.

See also Inspection and test plan · Technical data sheet

Waterproofing on the inner face, opposite the water — often the only option in an existing basement or a lift pit. Water reaches the concrete and pushes the coating from behind, so only a system designed for that is suitable.

Not the same as Positive-side waterproofing

See also Crystalline waterproofing

Related pages Positive vs negative side · Negative-side moisture

A two-component elastomer. Hot-sprayed grades are applied with plural-component equipment and set within seconds into a seamless, flexible membrane; cold, hand-applied grades cure more slowly. Performance depends on the rig settings and surface preparation.

Related pages Polyurea

Waterproofing on the face of the structure that meets the water, such as the outside of a basement wall. Water pressure presses the membrane onto the structure, and the concrete stays dry.

Not the same as Negative-side waterproofing

Related pages Positive vs negative side

The time a mixed multi-component material stays usable. After it, the material is discarded — not thinned or re-mixed. The value is in the TDS and shortens in the heat.

See also Recoat window · Technical data sheet

A sheet placed before the concrete is cast — under the slab or against the shoring — so the fresh concrete bonds to it. Post-applied membranes go on after the concrete has been cast and has hardened.

See also Positive-side waterproofing

Related pages Pre- vs post-applied

The first coat on the prepared substrate: it binds dust, seals pores and gives the membrane or coating a sound bond. Each system specifies its own primer; primers are not interchangeable.

Also called Priming coat (طبقة التأسيس)

See also Substrate · Recoat window

A board, screed or fleece placed over the waterproofing to protect it from backfill, traffic, tiling and other trades. It is not waterproof and does not replace the membrane.

Also called Protection board (لوح الحماية)

Not the same as Drainage layer

See also Separation layer

Related pages Protection & drainage

A dolly glued to the coating is pulled off with a portable tester; the force and where it breaks — in the coating, between layers or in the concrete — show the bond. ASTM D7234 covers concrete, ASTM D4541 metal substrates, EN 1542 concrete repair products.

See also Substrate

Related pages Checklist: Protective and anti-carbonation coatings

The period between the minimum and maximum time for applying the next coat. Too early traps solvent or damages the coat; too late can cost adhesion, so the system may then call for abrading or a fresh primer.

See also Pot life · Primer

A layer that stops plant roots reaching and damaging the waterproofing in planters and green roofs; some membranes carry a root-resistant additive instead.

See also Protection layer

Related pages Protection & drainage

Bitumen modified with polymers: SBS, an elastomer, gives flexibility, including in the cold; APP, a plastomer, gives more resistance to heat and UV. Both are used in torch-on bituminous membranes.

Related pages Bituminous membranes · SBS vs APP

A screed laid with slopes that lead water to the drains so it does not pond on the roof; lightweight foam concrete is often used to keep the weight down.

See also Inverted roof

Related pages Screed to falls

A fleece or sheet placed between two materials that must not bond or react — for example a PVC membrane against bitumen or polystyrene, or insulation boards under a screed.

See also Geotextile · Protection layer

Related pages PVC membranes

The surface a system is applied to — concrete, screed, masonry, steel or tiles. Its soundness, cleanliness, moisture and profile decide the bond.

See also Laitance · Substrate moisture test · Concrete surface profile

Checks that concrete is dry enough for the system: a plastic sheet taped to the surface shows whether moisture rises (ASTM D4263); probes in the slab measure relative humidity (ASTM F2170). The acceptable limit is set by the system.

See also Substrate · Dew point

Related pages Checklist: Resin flooring and microcement

The manufacturer’s document giving a product’s properties, uses, surface preparation, application and limits. Specifications refer to it, and product values are taken from it, never estimated. The SDS (safety data sheet) covers hazards and handling.

See also Method statement · Consumption rate

How the top edge of a membrane is finished: mechanically fixed with a metal bar, sealed, then covered by a flashing or set into a chase, so water cannot run behind it.

Also called Termination bar (شريط التثبيت)

See also Upstand

A layer of low thermal conductivity that reduces heat flow through a roof, wall or floor. It does not stop water: most insulation needs its own waterproofing. In Saudi Arabia, the energy-conservation requirements are in SBC 601 and SBC 602.

Not the same as Waterproofing · Vapour barrier

See also Inverted roof

Related pages XPS & EPS boards · Spray PU foam · Thermal insulation materials

Sheets that soften when heated, so their seams are hot-air welded into one homogeneous piece that can be checked along its length. EPDM, by contrast, is a thermoset rubber joined with tapes or adhesives.

Related pages PVC membranes · TPO membranes · PVC vs TPO

The last coat over a membrane or coating that protects it from sunlight, wear or chemicals; aromatic polyurethanes and polyureas, for example, need an aliphatic top coat where they stay exposed.

See also Liquid polyurethane membrane · Polyurea

BS 8102, the British code for protecting below-ground structures from groundwater, groups the approaches as Type A barrier protection (a membrane or coating), Type B structurally integral protection (water-resisting concrete) and Type C drained protection (a cavity that collects and drains water). Combining types adds resilience.

See also Hydrostatic pressure · Drainage layer

Related pages Basement protection types

The part of the waterproofing turned up a wall, parapet or kerb above the finished level so water cannot get behind it; it ends in a fixed, sealed termination, usually protected by a metal flashing.

Also called Turn-up (القائم)

See also Termination · Fillet · Flashing

A layer that limits the diffusion of water vapour, placed on the side of the insulation where the vapour pressure is higher, to prevent condensation inside the build-up. It is not waterproofing, and in the wrong position it can trap moisture.

Also called Vapour control layer (VCL) (طبقة التحكم في البخار)

Not the same as Waterproofing

See also Thermal insulation · Dew point

The ability of a material to resist water penetration to a limited degree and for a limited time, such as rain or splashes; it does not make the element waterproof. Common in product claims — check which test the claim refers to.

Also called Water-resistant (مقاوم للماء)

Not the same as Waterproofing · Damp-proofing

A continuous barrier that stops water passing through a building element, including water under hydrostatic pressure. It is designed as a complete system with its details: laps, corners, joints, penetrations and terminations.

Not the same as Damp-proofing · Water resistance

See also Hydrostatic pressure · Membrane

Related pages Systems · Waterproofing vs damp-proofing

A strip cast into a concrete joint to block water travelling along it: PVC or rubber profiles, or strips that swell in contact with water.

See also Construction joint

Related pages Construction joints

The thickness of a coat just after it is applied, read with a notched comb gauge. With the product’s volume solids it gives the expected dry-film thickness, so it is checked on every coat.

Not the same as Dry-film thickness

See also Consumption rate

Related pages Checklist: Liquid membranes