Dseal Bellow-Grade System

It is a below-grade expansion joint system that uses a flexible bellow membrane and robust retention to form a continuous waterproof barrier in foundations, tunnels and other underground structures. It is made in India by Dhawan Associates.

Below-grade means below ground level. The system is designed for buried structures where the joint must stay watertight against ground water and soil pressure.

A flexible bellow membrane spans the joint and is held by robust retention, forming a continuous seal that resists hydrostatic pressure while the structure moves.

It is used in foundations, tunnels, basements and other subterranean structures that require a watertight, movement-accommodating expansion joint.

Yes. The bellow membrane is flexible, so it absorbs expansion, contraction and settlement while keeping the waterproof barrier continuous.

The joint is prepared, the bellow membrane is centred over the gap, the retention is fixed to anchor it, and all laps and terminations are sealed before watertight testing.

Buried joints are largely inaccessible, so correct installation and testing are key. Where the joint remains reachable, such as in tunnels, it can be inspected periodically for damp or damage.

The Bellow-Grade System is a complete watertight below-grade joint, while the Water Barrier with Outlet is an above-structure accessory that collects and drains leakage beneath floor or deck joints. They address different parts of the structure.

The bellow shape lets the membrane stretch and fold with joint movement and settlement while staying anchored, which is essential for a durable watertight seal underground.

Yes. It is engineered to remain watertight under the hydrostatic pressure typical of structures below the water table, such as basements and tunnels.

Yes. As the manufacturer, Dhawan Associates can supply the system in configurations matched to your joint width and below-grade conditions.

It is manufactured by Dhawan Associates under the Dseal brand, a leading Indian producer of building expansion joint systems.

It is supplied across India directly by Dseal (Dhawan Associates). Call +91 93109 97953 for pricing and technical support on your project.

Yes. It is well suited to road, rail, utility and metro tunnels and other underground civil works that demand leak-free, movement-accommodating joints.

Dhawan Associates manufactures to ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 management system standards, covering quality, environment and worker safety.

Because buried joints are hard to access later, testing at construction confirms the barrier is continuous and leak-free before backfilling, avoiding costly repairs down the line.