How to Prepare a Subfloor for LVT Flooring in UK Homes
The most expensive LVT flooring problems often begin before the first plank is laid. A surface can appear dry, smooth and solid while hiding moisture, deflection, loose fixings or minor level changes that will affect a finished luxury vinyl floor. Effective subfloor preparation protects both click-lock and glue-down installations, even though the two systems have different tolerances.
This guide explains what to inspect on concrete, timber and existing floors, how to think about levelling products, and when to seek specialist advice. For suitable materials, browse our LVT preparation and installation accessories.
Begin with the flooring manufacturer's requirements
Do not start by buying a leveller or underlay. Establish the exact floor covering first. A flexible Luvanto Design dryback tile is bonded directly to an approved prepared surface; a Luvanto Click Plus rigid-core product floats on an appropriately flat, sound floor. Each has a fitting guide specifying permitted substrates and preparation. The standards can also differ between straight planks, herringbone and other formats.
Download the current instructions, identify the substrate and compare the flatness and moisture requirements before work begins. A generic instruction to make the floor 'level' is not enough. A floor can be sloping but consistently flat; a visually level floor can contain local bumps and hollows that cause trouble.
Inspect and document the existing floor
Remove loose covering or damaged material that the new system is not approved to overlay. Look for cracks, hollow patches, damaged boards, raised fasteners, grout lines, contamination, old adhesives and signs of damp. A straightedge can help identify high and low spots, but use the exact tolerance and measuring method set out in the flooring manufacturer's guidance.
Record problem areas with photographs and measurements. Where the substrate is uncertain, stop before covering it. A professional flooring survey can identify whether a local repair, complete replacement or approved overlay is necessary. Hiding defects beneath new vinyl is rarely a sound economy.
Preparing concrete screeds
Concrete and screeds need to be sufficiently sound and dry for the proposed floor assembly. New-looking concrete may still contain excess residual moisture; an old floor may have hidden damp or contamination. Use the moisture-assessment method specified by the chosen flooring and adhesive system, and do not rely on appearance or the fact that the surface feels dry to the touch.
Mechanical preparation may be needed to remove unsuitable paint, old adhesive or weak material. Once the base has been assessed, an approved primer and smoothing or levelling material can create a surface suited to dryback LVT. The exact drying and curing time must be observed before spreading adhesive or installing a floating board.
Preparing timber floorboards and plywood
Timber moves with humidity and loading. Secure loose or squeaking boards, replace rotten material and inspect the structure for deflection. LVT will not repair the underlying joists or turn a springy base into a stable one. Gaps and height changes between old boards can transfer through flexible dryback tiles unless a suitable overlay is installed.
Some systems use approved flooring-grade plywood or purpose-designed underlayment panels fixed to a specified schedule. Follow the exact board type, thickness, fastener spacing and joint treatment in the manufacturer's instructions. Do not assume arbitrary sheet material from a general DIY project provides a suitable LVT substrate.
Can LVT be installed over old ceramic tiles?
It depends on the condition of the existing tiling and the intended installation. Tiles must be well bonded, not cracked or hollow, with no underlying moisture problems. Grout joints and uneven tile edges can remain visible beneath thin glue-down vinyl. Rigid click floors still need the substrate to meet support and flatness requirements; they cannot simply bridge significant hollows.
An approved smoothing system may be suitable in some cases, but product compatibility and required preparation should be verified. Consider resulting floor height, appliance clearance and door thresholds as well as substrate performance. Removing old tiles may sometimes be the safer or more economical option.
What about existing vinyl or laminate?
Existing resilient flooring is not automatically an approved base. Loose edges, cushioned backing, trapped moisture and old adhesive can create an unstable surface. Some floating click systems prohibit particular old coverings. A layer that compresses underfoot can put stress on new click joints. Likewise, an adhesive for dryback may not bond to the old surface without a specially specified primer or removal procedure.
Read the floor manufacturer's permitted substrate list rather than assuming that more layers add strength. In older properties, flooring and adhesive materials may contain asbestos. Do not disturb suspect materials; seek assessment from a competent specialist before removal.
When do you need a floor leveller?
Levelling and smoothing products correct different problems depending on their formulation. A smoothing compound may fill small imperfections; a levelling underlayment may create a more consistent surface. Neither automatically fixes a weak, wet or moving structure. The preparation process may include mechanical grinding, patch repairs, priming or a manufacturer-approved overlay.
JJ Building Materials lists Luvanto Jumpax Basic floor leveller, with stated coverage of 2.88 m² per product unit. Check precisely how the system is installed, its compatible substrate and flooring, and whether separate components are required. Do not infer suitability for your job from the product name alone.
Moisture-control systems and vapour barriers
Different substrates require different moisture strategies. Residual construction moisture, rising damp and condensation are not the same problem. Some installations need an approved damp-proof treatment or vapour-control layer; others may be allowed after testing shows a suitable condition. The product's manufacturer should specify how moisture is assessed and what corrective treatments are permissible.
A generic sheet underlay cannot be assumed to be a compliant damp-proof membrane. For glued LVT, an incompatible moisture-control coating can also affect bond strength. Obtain a complete system specification that addresses preparation, primer, levelling, adhesive and floor covering together.
Subfloor preparation for click LVT
Rigid-core click boards still require regular support beneath locking edges. Pronounced dips can lead to movement, clicking noises or damaged profiles. Existing dust, grit and protruding fixings can also create problems. If a product has integrated acoustic backing, adding soft extra underlay is not a reliable way to overcome unevenness and may be prohibited.
Check the correct subfloor tolerance, approved underlay arrangement and perimeter gap requirements. Our LVT underlay guideclick versus glue-down comparison
Subfloor preparation for dryback LVT
Flexible glue-down tiles can telegraph minor defects in the substrate, so smoothness is particularly important. The surface must also be suitable for the selected adhesive and receive it under the conditions specified by the manufacturer. Poor preparation can cause visible ridges, weak adhesion or lifting at edges. Open times, working times and rolling methods all matter after the substrate has been prepared.
Use the approved LVT universal adhesive or high-temperature option as appropriate to the flooring and room, never simply as a substitute for substrate treatment. A successful glue-down installation is a chain of compatible layers, not just a tile stuck to the floor.
Tools, safety and site conditions
Preparation work can involve dust, sharp materials, chemical coatings and unfamiliar old flooring. Use the protective equipment and ventilation recommended in the relevant safety documentation. When grinding old surfaces, use appropriate extraction and avoid disturbing suspected asbestos-containing materials. Control room temperature and humidity, and keep the work area free of other trades during critical installation stages.
If the room has underfloor heating, follow the flooring manufacturer's heating shutdown, restart and temperature instructions. Avoid forcing a coating or adhesive to dry by turning heat up. Sunlit areas may need special protection during and after fitting.
Finished floor height and adjoining rooms
Subfloor preparation changes the final height of the new floor. A smoothing layer, approved overlay, adhesive and vinyl covering each add thickness, which can affect kitchen appliances, door clearance and threshold heights. A floating click board and a thinner glued tile may create different transitions to an adjoining hallway. Measure the complete build-up before buying materials, especially where the renovation involves several rooms.
When replacing old flooring, check the height at stairs, external doors and fitted units. A very small height change can still require an appropriate transition or an adjustment to the door. The LVT finishing and transitions guide
Final preparation checklist
Identify the exact LVT and fitting system; inspect the substrate; measure flatness; investigate moisture; fix structural movement; remove contamination; specify approved levelling and overlay materials; allow correct curing; and confirm accessories. Record any test results and keep the fitting instructions.
Once the foundation is ready, compare suitable luxury vinyl flooring and installation accessories with confidence.
Frequently asked questions
Can underlay level a bumpy subfloor?
No. Ordinary underlay is not a substitute for correcting substrate flatness or structural defects.
Do I need to remove old tiles?
Not always, but their bond, joints, flatness, damp condition and system compatibility must be checked.
Is concrete dry once it looks pale?
Not necessarily. Use the required moisture-assessment method for the proposed LVT assembly.
Can I fit LVT over loose floorboards?
No. Movement and loose fixings should be corrected before fitting.
Will glue hide unevenness?
No. Flexible dryback tiles can show through imperfections, while adhesive performance relies on a suitable substrate.