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The challenges of new-builds in retail

The challenges of new-builds in retail
Martin Cummins

Published by Martin Cummins - UK Technical Support Manager, Bostik

Martin has been involved in the industry for over 20 years. He’s passionate about flooring in all its guises, with his particular expertise being in subfloor preparation products and adhesives. Martin is an active member of the CFA manufacturers committee and he sits on the CFA council. He aims to keep abreast of all the changes in the industry and feeds this knowledge back to installers to make sure when floors are laid they perform to their maximum potential.

This is the time of year when many of us would normally be setting foot in shopping centres to buy Christmas presents, but of course many outlets in the UK are currently closed. Nevertheless, it’s always worth giving some consideration to what is a major market for our industry. Here are a few thoughts on preparing the subfloors for new-build retail environments – let’s all hope the situation picks up soon and we can start applying them widely again in 2021!

Flooring is a key component in shopping centres and retail locations. We may not realise it as we walk around, but a great deal of thought goes into getting this aspect right to create the visual, textural and ‘on brand’ experience as designed by the architects to persuade us to part with our money.

As is often the case though, the main focus from everybody bar us in the flooring installation game seems to be on the final finish, rather than what’s needed to achieve it. To that end, the first thing we need to know is if the project is a new-build or a refurbishment.

If we take the new-build situation in this article, then it’s pretty much as per any project. Evaluate the subfloor with particular reference to moisture content. Following British standards (8203 and 5325), the screeds/concretes etc. should always be tested using a surface hygrometer and, for any readings above 75%RH, a moisture mitigation system should be employed.

For expediency, there are very effective indicative moisture testing kits available which can identify whether floors are very wet, very dry or somewhere in between. It needs a great deal of experience and understanding of the particular indicative test kit to give definite recommendations, as they’ll behave differently depending on the nature of the subfloor – eg moisture content, surface compaction and density etc. So, the default should always be the surface hygrometer.

NOTE: The carbide bomb method of testing, as favoured by many concrete/screed manufacturers and installers is not relevant to installations of floor coverings. It measures moisture within a substrate, whereas the hygrometers measure the rate and level at which moisture will leave a subfloor. It’s moisture leaving the subfloor that is the potential risk to flooring installations.

Once the solid subfloors have been evaluated to test moisture levels, all other areas should be examined and established as suitable and stable. Always follow the current British standards or CFA guidance as to non-standard systems, and seek assurances that they have been laid to their relevant standards. We in the flooring game are not experts on how substrates prior to our trade should be laid, but unless we ask the questions it can be wrongly assumed we have accepted its quality. The link between suppliers of pre-flooring products, such as, but not exclusively, screed boards, underfloor heating systems, chipboard floors etc is difficult to form, as we all have our own technical agendas. Speak to the relevant manufacturer’s technical teams if you have any concerns or doubts as to the floor suitability and stability before you start work.

The selection of floor preparation materials will then be determined by the subfloor itself and may include epoxy DPM, moisture suppressants, bonding or isolating primers and smoothing compounds. If it’s a boarded floor then a minimum 6mm of SP101 plywood may be the answer to creating a stable floor – provided it’s firmly fixed itself.

It’s always advised not to simply opt for the cheapest of each individual component as this may lead to conflict and lack of support should anything go awry after the install. Also, we as manufacturers develop products to work in conjunction with each other, so it makes sense that you will be getting the best combination if you stick to a system.

With regard to non-standard areas of a retail store, there may be parts that have very high loading on the substrate from, for example, pallet trucks delivering product to the front of shop. These ‘vulnerable’ areas may need a higher strength smoothing compound to be used as it is unlikely the store will take care when manoeuvring materials. Generally a water mix product in these areas will be preferable.

There may also be back of house areas under similar conditions that are not receiving floor coverings. These will need a high abrasion finishing smoothing compound, otherwise they will gradually abrade and dust up, and may also may surface craze. When using wearing surface products be aware that they aren’t necessarily impervious, so any liquid spills will soak in and stain. It is advised that a thin coating is utilised should this be a concern. This is usually a low-build water dispersible product, and can often be pigmented to make walkways etc. stand out.

Other things to consider include the potential conditions that the flooring and adhesive systems might be subject to. The main culprits other than subfloor moisture are large temperature fluctuations and condensation, with cleaning systems also being part of the equation when it comes to futureproofing floors. Temperature fluctuations can include shopfront windows which receive direct sunlight, large atriums allowing significant sunlight in, poorly controlled underfloor heating systems, fridge and freezer cabinet areas which may not be on or indeed present during installations. Once the flooring is in place and bonded successfully, the adhesive bond line can be put under severe strain when the floor coverings try to expand or shrink. It is always worth using high temperature grade adhesives in any of these locations.

Furthermore with freezers, cold rooms etc., condensation may occur and in the worst case get underneath the floor covering, which will also cause failures. Using a chemical cure adhesive in these areas that isn’t affected by alkalinity and moisture is the correct way forward. Typically these are either epoxy or polyurethane products.

The challenges on new-builds are generally not as great as the weird and wonderful ones on refurbishment projects, which I will explore in another article.