FAQs

No – we recommend removing any painted finish from the subfloor before applying our subfloor preparation products. This is because the bond of the paint to the surface is unlikely to be of the required strength and could therefore lead to floor failure.

Yes – smoothing compounds can be used over bitumen, but it’s important to choose the right product.

High-performance smoothing compounds, such as our SL C955 ADVANCED, can be applied directly over bitumen residue (after removing as much of the adhesive as possible), whereas some standard compounds are not suited to be applied over a bitumen or old adhesive base.

You should never fill expansion joints with flooring products as there are other, more specialist products and profiles that are used for treating them.

Take a look at our in-depth guide to how to deal with expansion joints and other types of joints and cracks in subfloors.

When working on a refurbishment, it is recommended that you remove any existing adhesive to return the subfloor to a strong, sound base free of any contamination that could impair the adhesion of floor preparation products. However, some high-performance smoothing compounds, such as SL C955 ADVANCED are suitable for use over old adhesive residues.

Using the appropriate trowel size for the adhesive, apply it to the substrate while ensuring the notch size is correct and constant, as trowels can wear down on certain surfaces. Open time – the period between applying adhesive and installing the floor covering – varies by product and is influenced by ambient temperature and site conditions. Then place the flooring onto the adhesive bed.

Make sure you consult the Technical Data Sheet and contact our expert team if you have any questions.

The required amount of the adhesive will vary depending on the type of adhesive, the type of substrate, and the type of flooring (including its backing) you’re installing. The way the adhesive is applied will also determine the coverage rate.

Always consult the Technical Data Sheet and contact our expert team if you have any questions.

A smoothing compound creates a suitable surface for the adhesive and the floor covering to adhere to.

Calcium sulphate (or gypsum) screeds have become increasingly popular in recent years due to their quick drying times, ease of application, and thermal properties when used in conjunction with underfloor heating.

Before choosing which smoothing compound to apply, it’s important to understand the preparation process calcium sulphate substrates require to create a barrier to prevent the possibility of sulphates (within the screed) reacting with any cement-based smoothing compounds.

Yes – there are very few situations where selecting and using a suitable primer will not be necessary for the fitting, finish, and longevity of a flooring installation.

Our guide on how to select the appropriate primer discusses the most common primer options available in the market and how and why they should be used.

Floor primers enhance the flow characteristics of a smoothing compound, ensuring is spreads evenly and bonds properly to the subfloor.

They should be used on absorbent subfloors to seal the surface, helping to prevent pinholing. On non-absorbent surfaces, they promote adhesion and aid workability of the smoothing compound.

For Gyvlon® FD-E2C Flow Screed 92%RH or lower (without an underfloor heating system incorporated), the application of Bostik HYTEC E570 One Coat Membrane is recommended, followed by an undiluted coat of Bostik GRIP A936 XPRESS Primer or Bostik GRIP A526 UNIVERSAL Primer once the DPM has cured.

Find out more about Bostik’s compatibility with Gyvlon® Calcium sulphate screeds.

Pressure-sensitive adhesives are non-reactive, acrylic-based adhesives that offer excellent versatility and ease of use. Whilst a pressure-sensitive adhesive that is fully dry will retain a very tacky surface for a long time, most installations require that there is a transfer of adhesive to the floor covering that’s being installed. It’s therefore important to understand when and when not to use pressure-sensitive adhesives to achieve a high bond with a floor covering.

We offer several market-leading products designed to repair cracks, holes, gaps, and other damage in concrete floors prior to the application of a subfloor preparation system.

Our RENO E742 STRUCTURE is a solvent-free, two-part epoxy repair resin specifically designed for repairing cracks and filling joints in reinforced concrete and sand/cement screeds. The concrete floor crack repair epoxy resin effectively treats fractured bases, crack inducement joints (also known as control joints) and static cracks before the application of Bostik smoothing compounds or damp proof membranes.

Alternatively, RENO P520 EASY is a low odour, solvent-free, two-part repair polyurethane- and silicate-based resin for fixing cracks and filling shrinkage joints, with a drying time of up to 30 minutes.

Choosing the best adhesive depends on several factors, including the substrate, the floor covering specification and backing type, as well as the intended use of the floor – for example, areas subject to heavy rolling loads.

One example of suitable adhesive for a general installation of LVT is our STIX A640 PRESSURE SENSITIVE, a high-performance, solvent-free, pressure-sensitive flooring adhesive that provides an ideal base for the installation of LVT.

It has been specially formulated to give a high initial tack and excellent bond strength, and it dries to form a permanently tacky film, offering excellent adhesion as either a wet or dry-stick adhesive.