Waterproofing Systems for Saudi Projects: Membranes, Liquid Coatings, and What to Specify

Waterproofing performance depends on a system, not on a material name. The membrane or coating has to work with the substrate, joints, penetrations, drainage, protection layer and installation method. A good product can still fail if those details are wrong.

For Saudi projects, exposed roofs add strong solar and thermal exposure, while below-grade structures, wet rooms and tanks create very different conditions. The right question is which complete system suits the location, not which waterproofing material is best.

Start with the application and substrate

Before selecting a system, define whether the waterproofing is exposed or protected, horizontal or vertical, above or below grade, subject to hydrostatic pressure, expected to bridge movement, or intended for contact with stored water. Also define the substrate condition and how joints, upstands, drains and penetrations will be treated.

Product standards often describe material properties, not whether a particular roof or detail is suitable. ASTM D6222/D6222M for APP-modified bituminous sheets and ASTM D6164/D6164M for SBS-modified sheets both make that distinction.

Modified-bitumen sheet membranes

APP- and SBS-modified bituminous sheets are established roofing and waterproofing families. They are supplied as factory-made rolls, often with polyester or composite reinforcement, and may be smooth or surfaced depending on the system.

Application may be torch-applied, self-adhered or otherwise bonded depending on the product. Do not select APP or SBS from a generic claim that one is always better for Saudi heat. Compare the exact product data, reinforcement, thickness, flexibility, surfacing, installation method, protection and manufacturer-approved assembly.

Where open-flame work is restricted, a self-adhered or cold-applied system may be preferable, but that is a project and method decision rather than a universal rule.

Liquid-applied membranes

Liquid-applied systems cure into a continuous membrane and can be useful around complex geometry, penetrations and upstands where laps in sheet materials become difficult. Polyurethane, acrylic and other elastomeric systems should be evaluated by the actual product rather than by generic chemistry alone.

ASTM C836/C836M covers a specific class of high-solids, cold liquid-applied elastomeric membranes used on decks and walls where a separate wearing course, traffic course or backfill protects the membrane. That scope is a useful reminder that a standard number does not make one coating suitable for every exposed roof or traffic condition.

For liquid systems, specify cured dry-film thickness or coverage, primer, reinforcement at joints and details, substrate moisture limits, protection layer, curing conditions and the manufacturer’s exposure limits.

Cementitious waterproofing

Cementitious systems bond directly to concrete and masonry and are used in wet areas, tanks, pools and below-grade concrete depending on the product. Some are relatively rigid; polymer-modified products can accommodate more movement. Crack-bridging, water pressure and exposure conditions are product-specific.

For potable-water tanks, never assume a cement-based product is suitable because of its chemistry alone. Require explicit potable-water approval or certification accepted by the project and relevant authority for the exact product.

Synthetic sheet membranes

PVC, TPO, HDPE and other synthetic sheets appear in different roofing, below-grade and civil assemblies. Their performance depends on membrane formulation, reinforcement, seam method, substrate, protection and compatibility with adjacent materials. Avoid broad rules that assign one family to every roof or below-grade condition.

Factory-made sheets can give controlled membrane thickness, but seams and penetrations remain critical. For welded systems, the specification should state the seam method and required inspection or testing after installation.

How the application changes the specification

Roofs and podium decks: define whether the membrane is exposed or protected, expected traffic, solar exposure, movement joints, insulation arrangement, drainage falls, outlets and overflow paths. Waterproofing should not be used as a substitute for proper drainage design.

Bathrooms and wet areas: continuity at corners, floor-to-wall junctions, drains and service penetrations is usually more important than choosing between two reputable material families. Confirm compatibility with tile adhesive, screed and any protection layer.

Basements and below-grade walls: address water pressure, construction joints, penetrations, membrane protection and drainage. ASTM guidance for below-grade liquid-applied systems treats substrate, membrane, protection and drainage as connected parts of one system.

Tanks and pools: specify positive or negative water pressure where relevant, crack movement, immersion conditions, finish compatibility and any potable-water requirement. Review approvals and installation details before purchase, not after material reaches site.

Saudi climate considerations

For exposed waterproofing in Saudi Arabia, verify the exact product’s UV exposure limits, service-temperature range and required protective surfacing. On coastal or industrial projects, also consider chemical and salt exposure where relevant. These are product and location questions, not assumptions that can be made from PU, APP, PVC or another family name.

What to specify before requesting a quote

Define the application area and substrate; complete system and product standard where applicable; membrane thickness or liquid coverage; primer, reinforcement, laps or seam method; terminations, joints, penetrations and drains; protection course or backfill; substrate preparation and moisture limits; approved-applicator requirements; inspection and testing; warranty scope; and handover documents.

Bennahub can keep the waterproofing system, thickness, detailing and documentation requirements attached to the same line items sent to suppliers, so different quotes are easier to compare on the same technical basis.

FAQs

Is APP always better than SBS for Saudi roofs?

No. Both are established modified-bitumen families. Compare the exact sheet, reinforcement, surfacing, installation method and approved roof assembly rather than selecting from a generic climate claim.

Can a liquid membrane be used everywhere?

No. Liquid-applied products have defined substrates, thicknesses, protection requirements and exposure limits. Match the specific system to the application.

What matters most in a waterproofing quote?

Make sure suppliers are pricing the same complete system — including preparation, primer, membrane, details, protection and testing — rather than comparing only a price per square metre.

The most reliable procurement rule is to specify the assembly, not just the membrane. Waterproofing succeeds at the interfaces, and those interfaces need to be part of the scope before pricing begins.