Case Study – Type A and Type C Waterproofing


The scope of the project was to facilitate a combined waterproofing solution.

For any structure below ground, either fully or partially, waterproofing is essential for protecting and preserving integrity.

BS 8102:2022 defines the three main methods of waterproofing protection as Type A (Barrier), Type B (Structurally Integral) and Type C (Drained).

When choosing and installing waterproofing protection, consider the structure, ground conditions, and intended use. It’s advisable to use two types of waterproofing, known as combination protection, for habitable spaces. These systems should have different performance traits to reduce failure risks. Ensuring consistent protection and assessing the compatibility of different systems is crucial to lower risk and avoid later adjustments.


The structure required a new concrete slab which enabled the specification of Delta Amphibia, a Type A System and Delta Cavity Drainage Membranes, a Type C System.

Phase 1

Before the concrete slab was poured, Delta Amphibia, a primary waterproofing solution, was applied in a Type A waterproofing application.

Delta Amphibia, a pre-applied, fully, and permanently bonded waterproofing membrane (active core liner), has unique features – it’s four active layers: a Waterproof Barrier, a Reactive Core for self-sealing and healing, an Active Barrier that resists water movement, and a strong Bonding Layer which will form a permanent mechanical bond with fresh concrete.

Pre-applied bonded membranes are used to waterproof concrete in basements and below ground structures on the positive side (outside). They are installed before the reinforcement underneath a base slab and vertically on a soil retention system, or in a formwork.

Phase 2

Prior to the installation of the Type C System, measures were taken to mitigate the hazard of free lime leaching. This was accomplished through an application of Koster Polysil TG 500.

Continuity is crucial for successful construction and waterproofing. BS 8102:2022 places emphasis on good planning, correct sequencing and that site management processes are in operation.

The Delta Type C System is suitable for new construction and renovations. It features BBA certified cavity drainage membranes, drainage conduits, chambers, sump pumps, and high-water level alarms and/or control systems.


This reliable, top-quality combined system approach meets the highest industry standards for comprehensive structural waterproofing.

Whatever the needs of your project, you can rely on Delta’s Technical Team to ensure you get the right advice, support, and practical help at exactly the right time its required. Contact Delta today.

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