DRYflex Injection systems

Drytech restoration systems are based on injecting from inside underground structures: no excavation or demolition is required and, above all, there is no impact on a structure’s activities.


> Non-invasive: no excavation or demolition, with accurate work carried out on infiltration.

> Instantly verifiable: effectiveness of an injection can be checked by visual inspection.

> Always effective: it is always possible to intervene, even in the presence of water under pressure.

> No preparation of cracks: DRYflex resin acts though pressure. The condition of cracks does not affect the resin’s effectiveness and no cleaning or preparation is required.

DRYflex Resin Foam and elastic

When the resin is injected it has the same viscosity of water: it therefore fills cracks, joints, cavities, gravel pockets and concrete voids.

In just a short time, the elastic resin catalyses and expands, sealing the crack through pressure. If there is any movement in the crack, the resin expands further, thereby making the waterproofing secure.

This reactive and reversible swelling effect remains constant and allows the resin to adjust to any movements in the crack, ensuring the waterproofing remains effective over time.

Photo: the DRYflex resin fills the small cracks, following the length of the wall, and the gravel pockets.

DRYflex Resin Stronger than water

DRYflex is also completely effective in the presence of water.
The machine used for injecting can produce a very high pressure level – a few hundred bar – countering any water pressure.
This means that the Drytech system can also be used to restore active or inactive dams.

The photo shows the restoration of a joint in the Milan metro system: despite the groundwater pressure, the resin expels the water away and seals the joint through the whole thickness of the structure.

DRYflex Resin Stops water without stopping the trains

Drytech restoration systems are based on injecting from inside underground structures with minimum or no impact on the structures’ activities.

For example, in the case of a metro tunnel, there is no need to block or interrupt the service because the work is done during the night. Work on underpasses does not affect the flow of traffic above.

In an underground car park, the work only temporarily affects a couple of parking spaces at the injection point.

When restoring a dam, there is no need to empty the reservoir because DRYflex resins are also effective in the presence of water under pressure.

Video: the restoration of a metro tunnel. Work was carried out during the night without affecting the normal train service.

Restoration Curtain grouting

Curtain grouting waterproofs structural elements which are particularly porous or permeable (brick, stone or Predal walls) creating a resin membrane between the wall and the diaphragm or between the wall and the ground behind.

The resin is injected through a grid of holes and spreads from each point radially, creating an elastic, foam surface in the area behind the wall. It also fills the joints between bricks, stones or predal sections (see picture).

Curtain grouting techniques comply with the WTA 4-6-98 recommendation.

Restoration Ex-Post 3D plans

Rilievo Laser (laser survey) is software which permits a genuine ex-post 3D plan of a structure, fully mapping the restoration work carried out.
Rilievo Laser allows one to move virtually inside the restored structure and consult data and images of each relevant aspect such as position, size, type of work, quantity of material used and photos before and after the restoration.
The file is given to the customer as part of the Drytech Quality Dossier and allows issues to be verified: for example, to identify if any infiltration post-restoration comes from areas already treated.

The software was developed in 2009 by Drytech Engineering in collaboration with SIR from Turin, to be used during restoration of the Algiers metro.
On completion of the restoration work, Drytech gave the Algerian Ministry of Transport a detailed electronic plan of the work carried out along the 4 km of tunnels and 5 stations.

References Drytech® Restorations


Drytech® is the leading expert on waterproofing in groundwater for architects, engineers, building firms, estate agents and public agencies.

We have been specializing exclusively in waterproof structures and restoration activities since 1963, working directly on building sites throughout Europe.


Drytech International
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