We proposed the application of Master Builders Solutions 930/933 waterproofing bandage system that is specifically designed for applications such as this in the drinking water industry.
Initially all areas where the bandage was to be adhered was prepared by method of vacuum controlled diamond grinding to ensure a clean and laitance free surface for the new waterproofing to adhere to.
Concrete laitance is a layer of weak and powdery material that forms on the surface of freshly poured or improperly finished concrete. It consists mainly of cement and fine particles of sand and aggregate that rise to the surface during the curing process. Laitance can negatively impact the bonding of subsequent layers of concrete, coatings, or adhesives applied to the surface. It is typically removed through mechanical means such as grinding or sandblasting to ensure proper adhesion and a smooth finish for subsequent applications. Proper concrete curing and finishing techniques can help minimize the formation of laitance.
Climatic monitoring was instigated to ensure that the manufacturers instructions for use (IFU) were strictly adhered to.
As per the manufacturers recommendations the areas of the waterproofing bandage not to be bonded were masked off with tapes prior to installation. The central section of the bandage is deliberately not adhered in order to allow maximum elongation over a free moving area.
The width of bandage employed had to be varied in order to ensure proper adhesion either side of the panel gaps which was of varying widths.
A challenge for this waterproofing project was the access. With no edge protection in place we had to install approved anchor points and work from safety lines in a restraint function, utilised in such a manner that it was not physically possible to fall over the edge.
In total 3 tank roofs were waterproofed in this manner across two sites in Devon and Cornwall.
