Hyseal should be applied at the initial construction stage whenever possible.


Waterproofing a structure after it has been discovered that the concrete is porous or the structure leaks is time consuming, expensive and disruptive. The same is also true when surface treatments or finishes have already been applied to the concrete.

Costly shutdowns and damage from water ingress, leakage or flooding can be avoided by specifying Hyseal at the design stage and applying it during the original construction.


Foundations, Slabs and Construction Joints

Ideally, Hyseal concentrate should be added to fresh concrete at time of mixing, as an admixture, ensuring Hyseal’s unique waterproofing properties are immediately active throughout the freshly cast concrete. Wherever this opportunity has been missed, Hyseal should be applied as a slurry or dry-shake application over blinding concrete so that it is sandwiched between the binding and the slab. This will prevent ingress of ground water during the initial construction stage, thereby preventing the problems of damp and flooded slabs. Apply Hyseal slurry coats to all construction joint details of slabs and decks.

Foundations should be treated on the external face where possible with Hyseal slurry and mortar coats.

Water Retaining Structures

It is essential that Hyseal is applied as early as possible to the inside face of any water retaining structure so as to allow the crystalline growth reaction to develop throughout the concrete. The added advantage of applying Hyseal to water retaining structures is that the reaction will continue to take place when the structure is filled with water, effectively using the retained water to cure the Hyseal system and continue the crystal growth.

Two coats of Hyseal slurry should always be applied at right angles to each other to ensure elimination of pin holes. When renovating existing water retaining structures, the Hyseal should be applied immediately after the structure has been drained, thereby utilising the soaked concrete to gain optimum benefit for the Hyseal crystalline reaction.

Water Excluding Applications

Hyseal can be applied immediately after the formwork has been removed, as the water curing process for Hyseal will also assist in correct curing of the concrete. If an aesthetically pleasing finish for fair-faced concrete structures is required then a sand/cement render should be applied over the Hyseal slurry after initial curing period. The render can then receive the desired finish.

Positive and Negative Water Pressure

Hyseal is equally effective against POSITIVE and NEGATIVE water pressure. However, when Hyseal is applied against NEGATIVE water pressure, it is recommended that a sand/cement render of at least 10mm thick is applied over the two slurry coats of Hyseal to assist the crystalline process in combat ting NEGATIVE water pressure.

For concrete in existing structures more than 5 years old, it is also recommended that a render is applied over the two-coat slurry system. Hyseal works effectively on old concrete but a quicker reaction will occur with the presence of a render.


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