In an urgent inspection, Richard Renouf deals with an installation where the professional
floorlayer comes unstuck and blames a manufacturing fault.

TODAY’s visit was another urgent one. Every day the property owner was losing at least £250 in short-term rental and the flooring contractor was adamant this cost was going to be recovered from the manufacturer as it was a definite manufacturing fault. It had to be! The flooring had been fitted exactly according to the instructions.

The flooring was an engineered wood product with a click profile so it could be fitted as a floating floor over underlay. The side joints were to be connected at an angle, then laid flat to lock the joints together. The headers had an HDF profile inserted into the engineered wood layers to snap into place and hold them together. The boards were supplied with left- and right-handed profiles and the flooring was intended to be arranged in a herringbone pattern.

Herringbone pattern, a traditional layout for woodblock flooring, has also been popular for dryback LVT for a long time. In recent years the design has spread to laminate, click-LVT and engineered wood products for professional and DIY installation.

In this case the installer was a professional floorlayer with many years’ experience, but he’d never installed this product before.

As the call was booked in haste the installer couldn’t meet me onsite. There was a key safe, and once I was there I called him for the code and let myself in. The property was a converted chapel and the former sanctuary was completely open-plan and about 400sq m in size.

There was a ramp up to the old vestry which was now a games room complete with a pool table, and all the side rooms had been turned into bedrooms to sleep as many guests as possible, although I wasn’t too sure about the bunk bed made from two super-king double beds wedged into a room only big enough for them to be screwed to the wall on each side.
There were yet more bedrooms in the old gallery but these were all carpeted and, although they were badly fitted and rucking already, I wasn’t there to look at these.

The first sign of installation issues with a floating floor is usually failure of the header joints. Compression damage caused by lack of expansion room will distort the joints. LCT products will show a distinct crease line where the joint profile bends upwards under stress and laminate flooring does the same, but usually curving upwards rather than creasing.

The exposed edges of the wearlayer on either product is vulnerable to chipping and breaking, and this is usually what causes the end-user and the installer to assume the product is faulty.
Engineered wood behaves in a different way because it’s more robust. Lack of expansion room will cause the whole area to lift, sometimes dramatically. Ultimately rows can break apart – at least on a straight-laid plank design.

This flooring, however, looked more like it had been hit by an earthquake. One complete ‘row’ had separated in a zigzag along the header joints from the front to the back of the fitted area. Two other rows, and the ramp area, had 3-4m of separating joints with the remainder of the rows remaining locked together.

Each affected joint line was sitting on an uneven part of the subfloor. The original floor had been retrofitted with a hydronic underfloor heating system set into a screed and as the flooring hadn’t been acclimatised, the resulting shrinkage when the heating was on had found the weak spots – in this case the uneven header joints – and these had given way.

Further issues were created by the lack of expansion gaps, liberal use of silicone sealant, and the fitting of a large kitchen island with stone worktop directly on top of the floating flooring.
With a standard planked click-lock product there are fewer header joints per metre along the length than side joints across the width and the header joints are simple overlapping profiles and so have much less resistance to separating compared to the interlocking side profiles.

A few products have interlocking end profiles, but then have to be assembled along an entire row end-to-end before fitting the row to the tiles that are already down. With herringbone, however, the headers cannot be made to interlock as this would make it impossible to fit side and header joints. This means the zig-zag joint lines between each herringbone row aren’t as robust as the side-to-side joints between the planks in each row. In due course the installer tried to argue that this clearly meant the flooring wasn’t fit-for-purpose.

The manufacturer responded that the flooring came from a large production batch without other recorded issues and the case was closed.
www.richard-renouf.com
Richard Renouf is an independent flooring consultant