Installation Guide: Laying 20mm Engineered Oak Flooring
Marchand engineered oak is a 20mm board with a 6mm European oak wear layer, laid glue-down, direct stick, onto a prepared substrate. It is not a floating floor and it is not a click system. Laid the way this guide describes, it does not need expansion gaps and it stays where it is put. This page is the full installation guide; the printable version is at the bottom.
We are not installers. What follows is what experienced flooring installers have taught us over many floors, written down so that a builder, an installer or a well-prepared owner-builder can see what a good result depends on before the adhesive is opened. For anything complex, or where a subfloor is in doubt, use a professional installer. We can recommend installers we trust in most parts of New Zealand.
Before the flooring arrives
Most flooring problems begin under the floor. Three things need to be true before the boards come inside.
The building is closed in and dry. Windows and doors are fitted, wet trades are finished and dry, and the space is at the temperature and humidity it will live at. Relative humidity between 40% and 60%, and a room temperature between 16°C and 27°C, is the range the floor is designed for.
The substrate is flat, sound and clean. Flat means within 2mm over a 2m straight edge. High spots are ground, low spots are filled with a levelling compound, and on strandboard or an existing timber floor the joints are sanded flush so there is nothing for a board to bridge. The surface is swept and vacuumed, with no dust, paint, curing compound or adhesive residue left on it.
A concrete slab is dry enough. Slab moisture must be at or below 5% by weight, or 65% relative humidity by in-slab probe, before a primer goes on. New slabs take longer than programmes allow for. Test rather than assume, and keep the result with the job file.
Tools and materials
- Marchand 20mm engineered oak flooring
- Flexible wood flooring adhesive and a 6mm notched trowel
- Concrete primer, where laying on a slab (available from Marchand or any good flooring supplier)
- Tapping block or an off-cut of flooring, and a rubber mallet
- Saw and jigsaw, tape measure, pencil, straight edge and chalk line
- Weights: unopened flooring packs or 20-litre containers filled with water
- Safety glasses and gloves
Step 1. Acclimatise the boards
Bring the packs into the room where they will be laid and leave them for at least 48 hours, so the boards settle to the temperature and humidity of the space. Keep the packs flat and closed until you are ready to lay. Where underfloor heating is fitted, the system should have been running for two weeks before the boards arrive and the boards need 48 to 72 hours in the heated room; the full requirements are on our underfloor heating page.
Step 2. Plan the layout
Decide the board direction with the room, not the packs. Boards usually run with the longest wall or towards the main light, and in an open-plan space the direction should carry through without a change at a doorway. Start from the most visible, straightest wall and snap a reference line so the first row is dead straight; everything else follows it.
Lay out a few rows dry before gluing. Stagger the end joints so that joints in adjacent rows are at least 300mm apart and no short end pieces cluster together. Each pack holds three full planks and up to two split planks cut at random lengths, which is what gives the floor its natural rhythm. Plan so that the last row against the far wall is not a sliver.
Step 3. Prime a concrete slab
On concrete, apply a primer to the whole slab as the primer manufacturer directs and let it cure. The primer keeps slab moisture in the slab rather than letting it migrate into the oak, and it gives the adhesive a surface it can hold. Skipping it is the most common cause of a floor that cups or lifts a year later, and it voids the warranty.
Step 4. Apply the adhesive
Spread a flexible wood flooring adhesive with a 6mm notched trowel, working in areas you can cover with boards before the adhesive skins. Spread evenly; ridges of the right height give full contact without squeezing adhesive up between the boards.
Keep the adhesive out of the tongue and groove. Adhesive in the joint holds the boards apart, leaves air pockets and shows in the finished floor. Tap boards together with an off-cut of flooring or a rubber block and mallet, never with a steel hammer directly on the edge.
Step 5. Lay the floor
Set the first row on the reference line, groove to the wall, and check it twice. Lay following rows working away from it, staggering the end joints as planned, and pressing each board firmly into the adhesive as it goes down. Cut boards with a fine-toothed blade to fit around doorways, pipes and returns, cutting from the back face to keep the edge of the lacquer clean.
Marchand boards do not require expansion gaps or expansion joints within a room. The engineered construction (a 6mm oak face over a cross-bonded eucalyptus core with a birch backing) is stable enough that the boards can run to the wall or skirting. Leave only what the skirting or scotia needs to cover.
Step 6. Weight the floor
Adhesive needs the boards held down while it cures. As each area is laid, place weight on it: at the start of the job the unopened packs do the work, later on 20-litre containers of water do. Leave the weights for 24 hours and keep traffic off the floor for the same period.
Step 7. Finishing
Cut the last row to width and set it with the same care as the first. Fit transition bars where the oak meets tile, carpet or another floor; Marchand supplies stair treads and nosings and brass and metal transition profiles made for the 20mm board. Once the weights are off, vacuum and clean the floor as the after care guide describes, and cover it if other trades are still working in the space.
Wet areas
We do not recommend engineered oak on a bathroom floor, and showers and anywhere subject to standing water sit outside the warranty entirely. Where a floor runs into a laundry or a toilet, the surface and the joints within 1.5m of any sanitary fixture must be sealed with an impervious coating. Our Specification and Compliance page sets out the E3 test evidence and the scope of our Alternative Solution.
Frequently asked questions
Can Marchand flooring be laid over concrete?
Yes. It is laid glue-down over a primed, flat, dry slab. Slab moisture must be at or below 5% by weight or 65% relative humidity before priming, and flatness within 2mm over 2m.
Does it need expansion gaps?
No. The 20mm engineered construction is stable enough to run to the wall. Leave only what the skirting or scotia will cover.
Can it be floated or clicked together?
No. Marchand boards are tongue and groove and are always fully glued down. That is what gives the floor its solid feel underfoot and keeps it quiet.
How long does it need to acclimatise?
At least 48 hours in the room, in closed packs. With underfloor heating, 48 to 72 hours in the heated space after the system has run for two weeks.
Which adhesive should be used?
A flexible wood flooring adhesive applied with a 6mm notched trowel, with a primer first on concrete. Ask us or your flooring supplier for a current brand recommendation for your substrate.
Can I install it myself?
A capable builder can, following this guide exactly. The warranty requires installation by a qualified installer in accordance with the guide, so for a warranted floor use a professional. We can recommend installers in most regions.
The printable guide
The same guide as a PDF, for site or the job file.
Download the Installation Guide (PDF)
Related
- Underfloor heating with engineered oak
- After care guide
- Warranty
- Technical specifications
- Stair treads and stair wraps
- All technical documents
Last reviewed September 2026.