Floors often have to contend with high levels of foot traffic and heavy loads, as well as moisture, while retaining their integrity and aesthetic appearance. This was the case where we were recently called to recommend steps for refurbishing floors at a cash and carry in Manchester.
Assessment
As the store was still in operation, only a limited inspection of the floor could be carried out. However, the removal of a few existing vinyl tiles revealed that the subfloor was a concrete base with a power float finish, and had a total area of approximately 800m2. A pallet truck was operational at the time of our visit.
In one half of the store, there were signs of multiple floor failures that had been temporarily repaired. It looked like large freezers that were leaking could be causing issues. Fixed stanchions were located at each corner of the freezers.
Moisture tests undertaken using a digital hygrometer indicated that subfloor relative humidity levels were 92% in this area. In accordance with BS8203 Code of practice for installation of resilient floor coverings, floorcoverings should not be installed where a moisture test gives a relative humidity reading of more than 75% without a moisture management solution in place.
On the other side of the store, created by an extension 20 years ago and separated by an expansion joint, a small section of flooring was removed to reveal that adhesives were unaffected by moisture. Again, large freezers were situated in the area, with fixed stanchions at the corners.
First steps
Based on the available information, it couldn’t be determined for certain whether floor failure was being caused by excess subfloor moisture or water leaking from the fridges, or indeed if standing water was resulting in a high subfloor moisture reading. We therefore recommended a belt and braces approach.
Firstly, it would be necessary to remove all existing floorcoverings, subfloor preparation products and adhesive residues from the subfloors, along with any other surface contaminants that may impair adhesion, by mechanical means (such as shot blasting), leaving a clean, static, micro-textured finish. Any dust and debris would also need to be vacuumed away.
Second half
A single coat of Stopgap F77 waterproof surface membrane could then be applied to the half of the floor where excess subfloor moisture was detected to create a barrier between adhesives and floorcoverings. The product should be applied using a 1.5mm x 5mm v-notched trowel, before rolling with a pre-coated roller to achieve a continuous pinhole-free finish.
Once the waterproof surface membrane had cured, it was recommended that the surface was primed using F. Ball’s Stopgap P141 primer, which is specially designed to promote the application characteristics of levelling compounds when applied to non-absorbent surfaces, including waterproof surface membranes. The remaining areas could be primed using F. Ball’s Stopgap P131 general-purpose primer.
When the primers were dry, contractors were advised to apply a minimum 3mm thickness of Stopgap Green Bag levelling compound to create a perfectly smooth base for floorcoverings. Once cured, the fast-setting, low-odour, protein-free levelling compound has a high strength, making it suitable in areas subject to high foot traffic and heavy, wheeled loads, such as the pallet trucks.
Adhesive recommendation
Given the possibility of the flooring being affected by water from the freezers, we advised installing new floorcoverings using F. Ball’s Styccobond F73 PLUS heavy-duty adhesive, providing it is listed as compatible in the Recommended Adhesives Guide (RAG®). The solvent-free, moisture-curing adhesive delivers the high bond strength required to hold in place a wide range of textile and resilient floorcoverings, including rubber, vinyl, linoleum and synthetic grass, in areas that will be subject to heavy loads and high foot traffic, as well as surface water. Once cured, it is resistant to water, oil and grease.
Where movement joints are located within the base, all preparation products and floorcoverings would need to be terminated either side of the joint and a proprietary movement joint capping strip installed. If the stanchions were to be re-installed then these would have to be sealed where fixed to the floor to prevent an ingress of water.
F. Ball’s regional technical representatives provide advice to flooring contractors on how to get the most out of F. Ball products, including conducting site visits and producing case-specific reports advising on the best course of action for particular flooring projects. Find out who your technical representative is here.