THE PROBLEM
The new site cast concrete attenuation tank required a tank lining to waterproof the structure.
Attenuation Tank Lining, Watford
THE SOLUTION
We proposed the application of a highly elastic 100% solids solvent free tank lining in the form of Amchem Drythane. This material can elongate 125% making it ideal for water retaining structures such as attenuation tanks.
Initially all surfaces to be coated were prepared by method of vacuum controlled diamond grinding to remove surface laitance and contaminants in order to ensure proper adhesion of the tank lining.
The removal of the surface laitance during preparation works exposed lots of blow holes in the concrete which cannot be filled with paint alone.
All surfaces we damped down prior to applying a cementitious fairing coat to provide a surface suitable to apply tank linings to. This was left as a brushed finish to provide an excellent mechanical profile for the tank lining to adhere to.
This was allowed to cure and hydrate naturally prior to the introduction of heating and dehumidification to ensure that the fairing coat was sufficiently dry and the climatic conditions correct for the application of the tank lining.
As part of our standard tank lining quality assurance the moisture content of the substrate was tested and recorded using a Tramex moisture meter
Also as part of our standard quality assurance the climatic conditions were tested and recorded using a Defelsko Positector
All surfaces were primed using Amchem P-IV Primer. This highly damp tolerant polyurethane primer reacts with moisture within the concrete.
A stripe coat of Amchem Drythane was applied to all corners and edges to ensure full film build in areas where coatings pull thin through gravity and surface tension
Amchem Drythane was then applied in two coats to a nominal thickness of 500 microns per coat.
Regular wet film thickness readings were taken throughout the application process as part of our standard quality assurance in order to ensure that the desired thickness of tank lining was achieved to ensure the tank lining will perform as required.
