Abstract: The present invention relates to a multi-layer fluid delivery device for post-installation in-situ barrier creation. The device provides a medium for post-installation injection of remedial substances such as waterproofing polymeric resins or cementitious materials, insecticides, mold preventatives, rust retardants and the like. The device comprises a first layer and a second layer, with optionally an intermediate layer therebetween, and a plurality of tubes extending outwardly from the first layer. The first layer is preferably semi-permeable; the second layer is non-permeable; the optional intermediate layer is a void-inducing layer. The multi-layered device is attached to a structural substrate and a construction material such as concrete or shotcrete is applied against its surface (and around the plurality of tubes). Thereafter, a free flowing active substance can be injected through the tubes to fill the air space in the multi-layered device.