Underwater Protective Coatings by Scubapox from Bayset

Case History - Grafton City Council Basin Repairs

Products - NMP 1530 Thin-film superior protective coating

The Problem - Grafton City Council was loosing large amounts of water from an open storage basin. The down stream gully had constant flow even in dry times, which appeared to originate from the basin. A diver inspection revealed several large splits in the bitumen floor seal that would account for 10 to 15 1itres per second of flow.

The Solution - The long-tcnn water flow would have scoured out a significant section of the basin sub-structure, so it was decided to carry oul a two-part repair operation. A copper injection tube was inserted into the split seal area, followed by caulking sisal to stem the water flow. The bitumen-mixed sisal has been used for caulking timber boats and offered flexibility combined with easy application. NMP 1530 thin film protective coating was applied over the surrounding area to provide a permanent covering to the sisal. A high-density polyurethane grout was then injected under the floor using the copper tube, to provide support to the scoured out sub-floor area.

Notes/Comments - The project had an unusual outcome - the client was completely happy with the resulting stoppage of the leak, however the adjoining landowner was talking litigation for the loss of his 'natural spring'. The property had apparently been purchased with the added feature of a 'permanent spring' that never dries up... until now!