Matthew Mowfoth stresses the importance of ensuring the subfloor is correct before installing LVTs.
THERE are many factors to consider before, during and after the installation of your chosen LVT. Whether it be a commercial building or domestic property, the preparation of the subfloor is critical to achieve the perfect finish. Prior to installing your LVT, there are many questions which need to be addressed such as, ‘what’s the condition of the existing subfloor?, ‘do I need to raise the level of the floor?’ or ‘what’s the intended use of the area I’m installing the LVT in?’
Subfloor identification
It’s crucial to understand the different subfloor types to choose the appropriate products and installation steps. Concrete, sand/cement screed, ceramic tiles, bitumen and timber, are just a few examples of common subfloors which must be prepared appropriately before installing your LVT. However, there may be some cases where the subfloor needs to be removed to prevent subfloor failure, such as magnesite or wood blocks. It’s also important to consider the age of the building and whether there’s a functioning damp proof membrane (DPM) in place to control any residual moisture or rising damp, which could impact your LVT finish.
Moisture testing
Did you know that reportedly 90% of floor failures are associated with moisture problems? That’s why a moisture test must be carried out prior to installation. In certain cases, the floor you’re fitting your LVT on may not contain a DPM or the DPM may be damaged, which could lead to moisture impacting the longevity of your customer’s floor. When measuring moisture levels in the subfloor, you’re looking for a reading of less than 75% relative humidity (RH), which indicates the floor is dry and ready for the appropriate levelling and smoothing compound and adhesive for your LVT. If your moisture reading displays above 75% RH, then you’ll need to consider a moisture vapour suppressant (up to 95%) to tackle residual construction moisture or a damp proof membrane (up to 98% RH) to protect your floorcovering from ground bearing moisture.
Condition of the subfloor
Observing the condition of the subfloor is a critical part of the process before the installation of your LVT. The surface must be sound, clean, stable, and free from cracks and the presence of laitance. In some instances, mechanical preparation might be required to grind off any barriers to adhesion or repair products needed to fill holes. Addressing these issues correctly ensures a long-lasting base for your customers’ LVT.
Intended use of the area
Clear communication with the client is crucial before starting any subfloor preparation and installation. Setting expectations, discussing the intended use of the area, and addressing any specific concerns or requirements will help ensure a smooth and successful installation. By reaching a mutual understanding, all parties are aligned, reducing the chances of misunderstandings or dissatisfaction.
Movement joints
If you’re installing the LVT within a commercial building, there may be movement joints within the surface which need to be taken care of. Any movement joints can be brought through to the floorcovering using expansion trims, which need to be applied prior to the application of your chosen levelling and smoothing compound.
Levelling and smoothing compounds
Before LVT installation, it’s important to build up the subfloor to the appropriate height and achieve a smooth and level surface. Choosing the right levelling and smoothing compound will help ensure the British Standard SR1 (Surface Regularity) is met. You’ll also need to consider whether a primer is required, and if so, to make sure the appropriate primer is used, depending on whether the subfloor is absorbent or non-absorbent.
Adhesive selection and installation
The adhesive chosen for your LVT floorcovering plays a critical role in the floor’s durability and performance. Adhering to the manufacturer’s recommendations for adhesive selection is crucial to safeguard against potential installation issues. Different floorcoverings may require a specific adhesive, and straying from these guidelines can compromise the installation. Make sure the correct trowel is used for the adhesive by following the adhesive manufacturer’s datasheet. This ensures an even coverage of the adhesive and a strong bond between the subfloor and the LVT. In areas where the LVT will be exposed to high solar gain, such as conservatories or bifold doors, make sure you use an adhesive recommended for these heavy-duty areas. Finally, maximise the contact between the LVT and the adhesive by using a heavy roller.
Guidelines, datasheets and standards
Following the datasheets and advice of both the adhesive and LVT manufacturer throughout the installation process is best practice. From preparation of the surface before applying your chosen adhesive, to acclimatising your LVT to prevent expansion or shrinkage, the manufacturers’ datasheets will provide you with the guidelines to install the LVT in accordance with industry standards. Leading to long-lasting performance of your installation, and a happy customer.
Summary
To achieve a quality LVT installation, a high-degree of knowledge and skill is essential. From the preparation of the subfloor to the final finish, achieving a flawless LVT installation requires tackling challenges like moisture, subfloor stability, and LVT acclimatisation, but by adhering to best practice you can guarantee a perfect floor that stands the test of time.
01440 714939
info@ardex.co.uk
www.ardex.co.uk
Matthew Mowfoth is technical support manager at Ardex
