Koster VAP Moisture Mitigation System has been used to resolve the on-going problems experienced by Schneider Electrics at the companies Plymouth factory. The 30 year old factory floor had been installed without a vapour barrier. There were elevated PH and Relative humidity values affecting the whole factory floor and a 120m2 area had problems with osmotic blistering.
The concrete substrate seemed to be sound, but significant out-gassing had occurred when the previous primers and coatings had been applied.
Osmotic blistering is a common problem with epoxy and vinyl floors. The blistering is a result of water vapour rising from the concrete into the area immediately below the impermeable coating. The water vapour condenses as a highly alkaline liquid which destroys the bond between the concrete slab and the adhesive or coating. Problems of this type can be caused by a lack of a vapour barrier beneath the concrete slab. If there is a vapour barrier but the concrete was not given sufficient time to dry out before the application of the non-permeable floor finish, this can also result in osmotic blistering.
Testing of Core Samples
In order to fully investigate the problems with the concrete slab, Koster Aquatecnic advised the taking of test cores from the concrete and then subjecting them to a thorough analysis at an independent laboratory.
The core samples were taken by Florock Ltd (an approved VAP Installer) and they also tested the Relative Humidity and PH levels within the blisters. The laboratory testing was undertaken by Kiwa Ltd, who subjected the core sample to Infrared (FTIR) and Petrographic examination. The test results enabled Kiwa to determine the composition of the concrete and if there were any oil based contaminants or signs of ASR (Alkali silica Reaction).
Analysis of Results
The detailed analysis showed the concrete was quite porous but still strong enough to be shot blasted and receive the VAP treatment. There were only trace values of contaminants.
Applying Koster VAP Flooring System
Initially all static cracks, potholes and voids were filled with Koster VAP 2000 FS mixed with Koster Thickening Agent and then the floor was shot blasted to have a surface profile (CSP) of 3. The shot blasting process is critical as it removes surface contaminants and weak material. After completing the shot blasting the concrete is vacuumed to remove all debris, dust and dirt leaving a perfect surface profile.
Application of Koster’s VAP System is normally a one coat procedure, but on this project, Koster KB Pox IN was used as a pre-treatment. KB Pox IN is a very low viscosity epoxy resin with a good adhesion to damp surfaces. It is flooded on to the surface to fill open pores within the concrete and when cured, will significantly reduce out-gassing.
When the KB Pox IN had dried Koster VAP 2000 FS was applied at a rate of 400/sq.m and spread with a notched squeegee to a thickness of 0.36mm. The material was back rolled with a 10mm nap epoxy roller.
The VAP 2000 FS is a fast set vapour barrier and can be over-coated after 2-3 hours which makes overnight application possible.
Koster VAP Flooring System
The VAP system has unbeatable adhesion to the prepared surface, resists surface RH up to 100%, is VOC free and provides long term resistance to water vapour transmission.
The Koster VAP Flooring System should not be confused with a moisture tolerant primer which although it will adhere to a damp surface will not provide a published SD value and does not provide long term resistance to Vapour drive.
After 4 hours the VAP was carefully inspected and an Epoxy Fllor Top Coat was applied within 48 hours of the VAP application.
Koster VAP flooring Systems are always installed by an approved contractor and provide a guaranteed solution to the problems of vapour drive in both old and new concrete slabs.
Koster are one of the worlds leading authorities in the area of moisture mitigation and always provide an in depth and bespoke solution whether the project is for the repair of an existing floor or the prevention of future flooring issues in a new build.