After an extension over 30 years ago, this busy church hall suffered from ongoing moisture vapour problems. A new section of slab was poured to increase the hall area. A DPM was not installed under the old or new floor slab.
The floor build-up and vinyl finish deteriorated and had to be replaced in 1998. Moisture testing revealed elevated readings over 85% RH. The contractor at this time did not consider or understand vapour drive issues and re-instated the same build up and finish.
The busy church hall became unfit for purpose over several the years of use. The vinyl surface appeared very bumpy due to the accumulated moisture that had built up.
Koster Aquatecnic attended in January 2019 and obtain elevated readings of 99% across the 150m2 area. The recommendation to remove the vinyl and the degraded screed and install Koster VAP 2000 moisture control layer was put forward based on these findings.
The removal of the top layers revealed several issues. Patch repairs had been poorly made and infilled with a very weak concrete mix. 144 steel pins were left exposed from the slab and required to be cut off and infilled. The pins were (epoxy) mortared into the movement joint causing cracking to occur from the joint. The general condition of the slab was extremely poor.
Crack stabilisation was carried on the existing slab using Koster KB Pox IN and sand. The thin epoxy filled and structurally repaired the cracks. Because the slab was in such poor condition the area was primed and an appropriate screed build up installed. After 14 days the slab was shot blasted by the Preparation Group, Lincoln.
Kada Coatings then installed the coat of Koster VAP 2000 FS to the prepared surface. Koster FS-H was used in the movement joints and the Koster VAP 2000 FS was primed with Koster VAP 06 primer prior to the installation of the final screed by the main contractor.