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Curtain Injection

Post construction surface sealing for undergrade building components

Curtain injection: post‑construction sealing of structural elements with ground contact

Curtain injections are used for the post-construction sealing of structural elements with ground contact affected by moisture. Curtain injections are suitable for restoring basements, shafts, canals and tunnels. Curtain injection – also called gel injection – is mainly used if the structural elements concerned cannot be sealed from the outside or if this is not possible without disproportionate costs or effort. 

Curtain injections stop moisture penetration into the structure 

If structural elements such as e.g. masonry are not watertight, inadequately designed external sealants can be responsible for this. Other possible causes are aging processes of existing sealants, fluctuating ground water levels or movements within the structural element.

Water penetrates the building through voids, joints and defective sealants in the building and soaks the structure. Climatic fluctuations, in particular alternating frost and thawing, cause further damage, for example due to surface chipping.

Proven method for sealing structural elements with ground contact

Traditional methods of subsequently sealing structural elements with ground contact against moisture can be very time‑consuming and costly. The surfaces to be sealed must be laid bare, which detrimentally affects the surrounding infrastructure.

The reconstruction work is particularly problematic if adjacent areas of the building site cannot be used properly because of their location or because they are highly frequented (e.g. underpasses). In many cases, conventional exterior sealants cannot be put into place for structural reasons. Examples are buildings with partial basements or leaking floor slabs. Interior sealants on the other hand only hide the problem but do not protect the structure.

Sealing methods using injection gels also referred to as acrylate gels, hydro gels, polymer gels, hydro structure gels or methyl acrylates, have become established. Curtain injections make cost‑effective solutions possible also with difficult reconstructions of buildings.


Our products for curtain injections

WEBAC injection gels are used as injection materials for gel injections (curtain injections). The gel curtain permanently prevents the penetration of water and moisture into the structure.

WEBAC® 240
WEBAC® 240 + Bseal I

Curtain injection: techniques for the restoration

WEBAC® Injection Pumps
The air-operated 2C pump WEBAC IP 2K-F1 (stainless steel) is used for the application of acrylate gels. The two components of the injection material are introduced to the mixing head in separate hoses. The actual mixing process takes place here with a static mixer. 

WEBAC® Injection Packers
WEBAC mechanical packers with button head fittings are used to inject WEBAC acrylate gels. The injection pump is connected to the packer via a slide coupler. Alternatively, WEBAC hammer-in packers can be used if the structural element is solid enough. The packers are anchored by lamella arranged in a ring-shaped manner. In the case of masonry with a large number of voids or multi-shell masonry, the packers are equipped with an extension to prevent the injection gel from flowing back into the masonry.