Floors, Walls & Ceilings

FAST-TRACK FLOORING INSTALLATIONS FOR EDUCATIONAL FACILITIES

Flooring installations in schools, colleges and universities often face severe time constraints, as well as needing to be able to withstand significant levels of wear, including high foot traffic. Neil Sanders, Technical Director at one of the UK’s leading subfloor preparation product and adhesive manufacturers, F. Ball and Co., talks through achieving a long-lasting professional flooring finish in these locations while working to tight deadlines, including avoiding common causes of floor failure.

Ensuring a long-lasting, professional flooring finish in any environment requires following the basic principles of subfloor preparation, as well as using products that will enable flooring to withstand anticipated levels of wear and environmental factors. Incorrect or insufficient preparation can create the potential for floor failure, leading to costly recalls and remedial work. Projects in educational settings also frequently have to be completed over a weekend or during a holiday. Fortunately, the latest fast-track subfloor preparation products and adhesives for floorcoverings mean that flooring installations that have once taken a week can be done in a day, without compromising on quality. First steps

Before undertaking any flooring installation, a thorough assessment of the subfloor should be completed to ensure it is sound, smooth and free of contaminants. If the subfloor is a newlyinstalled screed, laitance (the crust of cement and fine aggregates that form on the surface of the screed as it dries) may still be present, and floors that are being refurbished may be contaminated with old adhesive residues. To avoid costly floor failure, both laitance and contaminants should be mechanically removed before proceeding with a flooring installation. Dust or debris should also be swept away, and damaged subfloors should be repaired with an appropriate floor repair compound.

Safeguarding against moisture

The next stage in any flooring installation should be to conduct a moisture measurement test to ascertain subfloor moisture levels. Unmanaged subfloor moisture, whether residual construction moisture or rising damp, is one of the leading causes of floor failure, causing adhesives to de-bond, carpet underlays to rot, wooden floors to warp and resilient floorcoverings to blister. Moisture can also lead to the growth of mould and bacteria, which may present a health risk.

To comply with British Standards, subfloor relative humidity (RH) levels within the subfloor should be measured using a pre-calibrated hygrometer. If RH levels exceed 75%, or 65% when installing timber floorcoverings, a moisture management solution will be required to stop excess subfloor moisture potentially causing floor failure.

Liquid waterproof surface membranes are the usual moisture management solution. The best-performing epoxy waterproof surface membranes will isolate excess subfloor moisture where relative humidity values are up to 98%, with a single-coat application, which will fully cure in as little as three hours.

Quicker, two-coat, water-based systems are available that will create an effective barrier against residual construction moisture where relative humidity values are up to 95%. The first coat cures in 15 to 20 minutes, and a further 30 minutes curing time is required for the second coat.

Prime importance

Once the subfloor is suitably sound, smooth and dry, with a suitable moisture management solution in place if required, it will be essential to prime the subfloor in almost all circumstances. When used over non-absorbent surfaces, such as epoxy waterproof surface membranes, priming promotes the adhesion of subsequently applied levelling compounds. Applied over absorbent subfloors, such as concrete, sand and cement screeds or plywood, priming also prevents the unacceptably rapid loss of water from the levelling compound into absorbent substrates, maintaining its working time.

Priming also prevents ‘pinholing’: small holes in the levelling compound that have the appearance of pinholes or blisters caused by the slow escape of air from absorbent surfaces as the levelling compound cures.

Creating a base

Once the subfloor is primed, the application of a levelling compound is recommended to create a perfectly smooth and sturdy base for the receipt of new floorcoverings.

The fastest setting products on the market are walk-on hard in 30 minutes and ready to receive new floorcoverings from 45 minutes.

In refurbishment applications, where old adhesive residues are present, an alternative fast-track solution is available: specialist high-performance levelling compounds that can be applied directly over bitumen and old adhesive residues, eliminating the need for mechanical removal. One such product, F. Ball’s Stopgap 1200 Pro, takes as little as 60 minutes to set and is ready to receive floorcoverings from as little as four hours. When the product is applied over old adhesive residues, it is not essential to prime beforehand, saving further time.

Where installations are expected to be subject to heavy loads and high foot traffic, the application of a heavy-duty levelling compound will ensure the long-term performance of the installation.

Choosing the right adhesive

Once the levelling compound has cured, the contractor can then select a suitably fast-working adhesive to install appropriate floorcoverings. The choice of adhesive will often be determined foremost by what type of floorcoverings are to be installed and where, but there are options for when timesaving is a priority.

Nowadays, adhesives are available that build up a strong enough bond to allow for foot traffic in less than an hour after the application of floorcoverings.

Carpet tile tackifiers are available that only take 30 minutes to form a permanently tacky film, which will prevent tiles from moving laterally under everyday traffic, while allowing individual sections to be easily lifted and replaced if damaged or worn.

Compatibility check

A final note on adhesive selection: it is always advisable to check the compatibility of particular floorcoverings and adhesives to ensure against floor failure. To do this, contractors should consult the adhesive manufacturer’s Recommended Adhesives Guide or see the floorcovering manufacturers’ instructions.  www.f-ball.com