How is parquet flooring laid?
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Solutions & Applications · Flooring
Most problems with timber floors do not stem from the boards themselves but from the subfloor and damp. The choice between glued and floating installation is not a matter of labour costs — it determines how the floor will move over the next twenty years.
It is the substrate that determines the quality of the work, not the board
Pre-polished multi-layer parquet is laid on concrete, cement screed, ceramic tiles, mosaic, marble, a wooden subfloor or fully bonded resilient flooring. In all cases, however, the same three conditions apply: level, dry and structurally stable. Old adhesives and residues must be completely removed before any work begins.
| Parameter | Requirement | Why |
|---|---|---|
| Flatness | 3 mm / 2 m · 2 mm / 1 m · 1.2 mm / 0.25 m | Localised voids cause gaps in the adhesive and noise under load |
| Concrete moisture | up to 90% RH (structural moisture only) | Does not cover floors on ground level, above boiler rooms or heated slabs |
| Acclimatisation of materials | ≥ +18 °C for ≥ 48 hours | Timber must be allowed to stabilise before it is cut and glued |
| Relative humidity of the space | 30–60% RH | Out of range, the board shrinks or swells after installation |
| Wet works | Integrated & dry | Render, mortar and paint introduce moisture into the space |
Substrate moisture measurement must always be carried out by a qualified technician, using appropriate equipment and following a standardised procedure — not by estimation. It is the least expensive stage of the project and the only one that cannot be rectified retrospectively.
Adhered or floating: the decision is made at the design stage
| Criterion | Adhesive installation | Floating installation |
|---|---|---|
| Floor behaviour | Fully bonded — minimal movement | Loose-laid on substrate — moves as a single unit |
| Expansion joint | 2–5 mm towards walls & fixed elements | 1.5 mm per metre of floor area, minimum 8–10 mm |
| Large surfaces | No restriction on continuous surface area | Requires partitioning with profiles in large openings |
| Designs & patterns | Essential (boards laid in different directions) | Inappropriate |
| Heavy floor elements | Permitted (kitchens, staircases, energy-efficient fireplaces) | Not permitted — they obstruct traffic |
| Acoustic comfort | Requires design — there is no intermediate layer | The underlay reduces impact noise |
| Time to full utilisation | 48–72 hours after bonding | Immediately |
| Replacement of a board | Difficult | Easy — detachable locking system |
In practice: glued-down installation is chosen when a seamless surface without thresholds is required, when elements are fixed firmly to the floor, or when the design calls for boards laid in different directions. The floating method is chosen for speed, reversibility and acoustic comfort in residential properties.
Moisture: the point at which the two methods diverge radically
In floating installations, a vapour barrier is standard practice: a polyethylene sheet across the entire subfloor, with an overlap of at least 200 mm at the joints. Tarkoflex II incorporates the vapour barrier function into the underlay itself; Tarkofoam II levels the surface and improves acoustic performance.
In the case of bonded installation, the opposite applies: a conventional vapour barrier cannot be installed, as it would prevent bonding. The protection is provided by the primer and adhesive system — or, alternatively, to a 0.20 mm sheet and plywood at least 12 mm above the concrete, in which case the parquet is glued to the wooden subfloor.
- Cleaning & dust control: prime the substrate before bonding.
- Water-free adhesive: Ceresit P 625 2C PUR is a two-component, water-free and solvent-free polyurethane — it does not introduce moisture into the board and cures regardless of the layer thickness.
- Consumption & priming: these figures are taken from the technical data sheet for the specific adhesive, depending on the relative humidity (RH) of the substrate — not from general tables.
Underfloor heating: three rules that are systematically breached
- Never use two damp-proof courses: in organic floor structures, moisture becomes trapped between the layers. Before adding a damp-proof course, check whether one is already present lower down in the structure.
- Surface temperature ≤ 27 °C throughout: this restriction also applies beneath carpets, cupboards and fixed furniture. Requires a self-regulating electric or properly designed hydronic system.
- Avoid sudden changes: rapid fluctuations in temperature place greater strain on timber than the temperature itself. The temperature should rise and fall gradually.
The layer beneath the pipe determines how much heat reaches the floor. ISOFLOOR slabs are high-density extruded EPS with pipe retention nodes: λD 0.035 W/(m·K) for EPS 150 and 0.034 W/(m·K) for EPS 200, with compressive strength CS(10) of 150 and 200 kPa respectively, at 50 mm or 75 mm intervals. The special edges join the panels into a single layer without thermal bridges, whilst the PLUS version features an integrated HIPS vapour barrier.
Step-by-step: adhesive installation
- Material inspection and sorting: several bundles are opened simultaneously and the boards are mixed together so that the shades blend smoothly. Boards with visible defects are not installed.
- Directional layout: in square rooms, the boards follow the light; in oblong rooms, they follow the long axis. In corridors, they should always run the length of the corridor.
- Final row check: the gap between bricks must not be less than 5 cm. If the wall is not straight, the first row must be split lengthways.
- Adhesive-free test layer: the row is laid dry, the last board is cut to size, and then lifted to allow the adhesive to be applied.
- Apply adhesive row by row: using a notched trowel, to the surface corresponding to a single row — never over an area larger than that which can be covered within the open time.
- Installation with wedges: board-to-board, with wedges towards the wall to maintain a 2–5 mm joint.
- Joint offset ≥ 500 mm: the transverse joints of successive rows shall be offset by at least 500 mm across the entire floor.
- Checking for gaps in the adhesive: during installation, tap the surface whilst it is under load; a hollow sound indicates a lack of contact and must be rectified immediately, not afterwards.
- Building expansion joints: where there is an expansion joint in the load-bearing structure, the floor must be interrupted.
- Protection & curing time: 48–72 hours before full use. Cover with moisture-absorbent cardboard, or with a board ≥ 12 mm thick if site traffic is expected. The tape must never be applied directly to the floor.
The most common mistake isn’t the adhesive — it’s the expansion joint that ‘disappears’ in the finish. A skirting board screwed tightly to the floorboard, a threshold with no gap, or a door frame that rests on the floor negates the entire movement design. The joint is covered; it is not bridged.
At ARGYNET, we specify the entire system — substrate, barrier, adhesive, finishes — and calculate materials per m².
Finishes: where the design is visible
- CLIPSTAR skirting boards: fitted using clips that are fixed separately to the wall — with no visible screws and without the skirting board being mechanically secured.
- Transition profiles: reducers for transitioning to thinner floors, square end profiles where a reducer cannot be fitted, and threshold profiles for separating large areas. All three incorporate the necessary clearance for movement.
- Stair treads: made from solid oak, fixed directly to a 14 mm board or riser.
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Adhered or floating — has the moisture content of the substrate been measured?
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