Engineered Wood Installation Guide
How to prepare, fit and protect an engineered wood floor. Site conditions, the three fitting methods, and what to do once the floor is down.
What makes engineered wood different
An engineered board is a real oak wear layer bonded to a cross layered core. The oak is what you see, walk on and eventually sand. The core is what stops the board moving. Because those layers run at right angles to each other, the board holds its width through the seasonal swing that makes solid timber cup and gap.
That construction is also why engineered wood is approved for underfloor heating while solid wood is not. It is the single most useful thing to understand before you choose, because it decides your fitting method, your subfloor preparation and whether the floor will work over a heated screed at all.
Before you open a pack
Fitting the floor too early is the most expensive mistake on this list, and it is entirely avoidable. Work through all four points before the packs are opened.
Get the subfloor right
A floor is only as good as what sits under it, and this is the step people judge by eye and later regret. The subfloor has to be dry, sound, clean and flat enough for the product and the method you have chosen.
Flatness is measured with a long straight edge, not estimated. Moisture is measured with a meter, not judged by touch. Both matter for a specific reason: a floating floor over a hollow reads as bounce underfoot and eventually stresses the joints, and a glued floor over a high spot never bonds there at all. Nothing later in the process fixes either one.
Choose the fitting method
Three methods, and the choice is usually made for you by the subfloor and the room rather than by preference.
Plan the layout before you start
Ten minutes of planning here is worth more than any tool you can buy.
After the floor is down
Almost all wear on a wood floor arrives on shoes. Grit is dragged across the surface underfoot and cuts the finish, so mats at every external door and frequent sweeping do more than any product you can buy.
Questions about fitting engineered wood
Can I fit engineered wood flooring myself?
How long should engineered boards acclimatise before fitting?
Which way should the boards run?
How much extra should I order?
What the published standards say
Each entry is quoted from its source and linked to it. The full set is in the standards reference.
Acclimatisation before fitting
The Contract Flooring Association's guide states that the room should be at its in-service temperature 48 hours before installation so that the flooring can be kept in the room and reach room temperature before it is laid.
| conditioning before installation | 48 h |
|---|
“They also advise that this temperature should be attained 48 hours prior to the installation, so that floorings can be kept in the room and brought to room temperature (acclimatised) before installation.”
Source: CFA Guide to Contract Flooring - Contract Flooring AssociationBS 8203 — relative humidity limit for a subfloor
UK practice following BS 8203 treats a subfloor as dry enough for resilient floor coverings when hygrometer readings do not exceed 75% relative humidity (65% RH for solid timber coverings), measured with a hygrometer sealed to the surface so that it reaches equilibrium with the base.
| RH limit, resilient floor coverings | 75 % RH |
|---|---|
| RH limit, solid timber floor coverings | 65 % RH |
“The base can be considered dry enough to install most floorcoverings if a series of tests produce readings not exceeding 75% R.H. (65% R.H. for solid timber floorcoverings).”
Source: F. Ball and Co. Ltd - Digital Hygrometer, Technical Data SheetThe hygrometer method for subfloor moisture
In UK practice a hygrometer is sealed to the subfloor inside an insulated box with butyl tape and left until the air under the box reaches equilibrium; at least 4 hours before the first reading on a 50 mm screed with the DPM under the screed, and 72 hours where the DPM lies below the base slab.
| minimum time before first reading, 50 mm screed with DPM between base and screed | 4 hours |
|---|---|
| minimum time before first reading, DPM below the base slab | 72 hours |
“For 50mm thick screeds, where the damp proof membrane is placed between the base and the screed, a period of at least 4 hours should be allowed before the first reading is taken. For thicker constructions i.e. where the damp proof membrane is placed below the base slab, a period of 72 hours should be allowed to elapse before the first reading.”
Source: Digital Hygrometer - Technical Data Sheet, F. Ball and Co. LtdBS 8204 — surface regularity classes SR1 to SR3
BS 8204 defines three surface regularity classes for screeds and concrete bases, SR1, SR2 and SR3, measured as the maximum deviation below a 2 m straightedge placed directly on the surface.
| SR1 (max deviation under 2 m straightedge) | 3 mm |
|---|---|
| SR2 (max deviation under 2 m straightedge) | 5 mm |
| SR3 (max deviation under 2 m straightedge) | 10 mm |
| straightedge length | 2 m |
“Surface regularity classes are given in BS 8204 as SR1, SR2 and SR3 relating to 3mm, 5mm and 10mm respectively.”
Source: Surface regularity - straightedge method | The Concrete SocietyThe expansion gap
The EPLF, the European association of laminate flooring producers, recommends an edge gap of 8 mm to 12 mm on all sides of a floating floor, so that the covering can expand and contract without lifting.
| recommended edge gap on all sides | 8 to 12 mm |
|---|
“To accommodate such changes, a edge spacing should be observed on all sides. A free space of 8 mm to 12 mm is recommended.”
Source: EPLF Technical Bulletin — Installation of Laminate Floor Coverings (06/2022), 6.4 Edge gapsRoom conditions at the time of fitting
The MMFA, the European association for multilayer modular floor coverings, requires the flooring to acclimatise for at least 48 hours in the same conditions as the installation area, stored flat and cross-stacked in unopened boxes at roughly 15-25 degrees Celsius and 35 to 65 per cent relative humidity.
| acclimatisation before installation | at least 48 h |
|---|---|
| storage and acclimatisation temperature | 15-25 °C |
| storage and acclimatisation relative humidity | 35-65 % |
“Leave the floor covering to acclimatise in the same environmental conditions as the installation area for a period of at least 48 hours prior to installation. Always store the boards flat and cross-stacked, in their original unopened boxes and at approx. 15-25 °C and between 35 % and maximum 65 % relative humidity.”
Source: Prior to installation — MMFA (Multilayer Modular Flooring Association)CFA guidance — the subfloor is the installer’s first responsibility
The CFA Guide to Contract Flooring requires the base to be a clean, sound, level surface that is strong enough to carry the preparation materials and the floor finish, mechanically prepared and dust free, and dry enough to give a hygrometer reading of no more than 75% relative humidity.
| maximum hygrometer reading before laying a floor finish | 75 % RH |
|---|
“Before the application of the floor finish a solid (cementitious or similar) base must be sufficiently dry to show a hygrometer reading not greater than 75% Relative Humidity when tested in accordance with the British Standard Code of Practice.”
Source: CFA Guide to Contract Flooring - Contract Flooring AssociationBS 8201 — installing timber and wood-based flooring
BS 8201:2011 is the UK code of practice for installing flooring of wood and wood-based panels; it gives recommendations on the material, environmental and installation factors that determine how the finished wood floor performs.
“BS 8201 gives recommendations and guidance on the material, environment and installation variables that combined have a fundamental effect on the performance and serviceability of finished wood flooring.”
Source: BS 8201:2011 - Code of practice for installation of flooring of wood and wood-based panels



