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ADVICE & INFORMATION

Richard Renouf

When raised access floors undermine finishes

Raised access flooring offers flexibility, but poor specification, overlooked expansion gaps and cost-
cutting decisions can quickly turn adaptable office space into a visibly failing floor, says Richard

AISED access flooring (RAF) usually where it was carpet tiles it showed as the walls, and wherever the panels
Rcomprises wood-based panels a single line, one tile back, where the came up to a structural element of the
overlaid on the top and sides with tiles were peaking along the joint lines building, there was an expansion joint
metal. These are installed on columns parallel to the frames. between the panels and the structure.
to create a floor with a void underneath ‘It’s solar gain causing the building It was only about 5 mm thick, but it
to allow for power and comms cables to expand, and the flooring contractor was necessary because the floor would
to be run to any part of the floor and, doesn’t want to know’ they said. ‘But expand and contract at a different rate
in theory at least, changed at will. This we’ve never had any problem with to the building.
can be very appealing to a client but can expansion of RAF panels, so we need to The flooring contractors had not
cause some poor decisions to be made understand what’s going on.’ taken this movement into account and
when flooring is being specified. had close-fitted the tiles against the
A flooring contractor wants – needs walls and window frames. Although
- a suitable surface for the flooring the amount of expansion was minimal
and, no matter how well RAF panels – millimetres over floor areas of 30
are fitted, the joint lines will invariably metres and more – it only takes a tiny
show through LVT and, in some less- amount of tightness to cause significant
well installed cases, will show through rippling. Of course, solar gain played a
carpet tiles, so it’s advisable to prepare part, but more to do with softening the
the RAF surface using a plywood tackifier and breaking its grip.
overlay or a suitable smoothing British Standards require that any
compound. This, however, can cause the expansion joints in a subfloor are
client to assume that this would prevent continued up to the flooring surface
the panels from being lifted easily if the although exceptions can be made
cables ever needed to be moved around. when the flooring is floating and the
This was the case with a recent subfloor is free to move. This is easy to
inspection where an additional remember when the expansion joints
constraint was cost. The client pared The flooring had been laid on a are between sections of a concrete
the specification back to the absolute tackifier which had been applied over slab or between sections of a building
minimum and, of course, complained the entire floor area. Some remedial because they are visible. In this case
when the flooring failed to perform well. work had been done to try to get the the joints looked more like a finishing
The property managers who had been tiles to lay flat using double-sided tape, trim for the RAF panels and I could
responsible for fitting out the offices but this had caused the adjacent tiles to understand how they were missed
asked me to take a look and advise ruck up instead. As we walked the floors during the laying of the flooring, but
was surprised they were not considered
them about a specific problem. We I noted rucking in other areas, especially when problems started to arise.
started on the sixth floor and as soon as where the flooring met structural The RAF panels had not been uplifted
we walked out of the lift lobby, the state features such as pillars. or swapped around since the building
of the flooring was very poor. One floor had not been leased and so had been occupied and in my opinion
The LVT tiles showed every joint line had been left with just the RAF panels the additional ‘hassle’ of lifting and
in the uneven RAF panels. This was not exposed. These were very uneven replacing panels - if it ever became
the issue I had come to see, and I was and it was obvious that whoever had necessary - was more than worth the
asked to ignore it as the client had not needed to lift any panels did not have very poor appearance of the installation
complained about this. the right tools and so had levered them because no interlayment had been used.
They took me towards the windows. up along the edges causing the metal to But they tell me the customer is always
It was a modern office building with full buckle. This would need more surface right and at least this had not been part
height windows on all four sides and preparation than ever when it was time of the complaint. 
along the floor level frames the flooring for flooring to be laid. But I looked at www.richard-renouf.com
was lifting and buckling. Where the some other details. Around the entire Richard Renouf is an independent
flooring was LVT this was severe and perimeter where the RAF panels met flooring consultant

www.contractflooringjournal.co.uk 71
@CFJMagazine CFJ April 2026