The overlap is a variation of an architectural classic.
According to Doug James, its roots may go as far back
as the late art deco period. In some ways, the overlap
is similar to the raft, but the overlap is more likely to
appear to be part of the fabric of the building.
The overlap comprises a series of ceiling or wall planes
layered on top of each other and lighting is installed
in the spaces between. The bleed of light separates the
A single layer could be described as an overlap if
it deliberately separates a surface, giving it its own
identity in the space. The technique has three primary
functions, says James. The first is to create rhythm. In
an airport corridor, an overlap installation can break
up the visual monotony of a longitudinal space.
A second function is to suggest grandeur. ‘A lot of
ballrooms have layered ceilings,’ says James.
The technique can also create visual interest in what
could otherwise be a fairly mundane space. Layering
of light on plain walls or ceilings can make a strong
There are other specific applications for the overlap.
For instance, an architect may be unhappy with the
way a column meets a ceiling. It is a relatively simple
task to pull a few layers out of the column and let light
bleed out onto the ceiling.
Similarly, the overlap could conceal the end of a slab
that comes from an internal space into an atrium.
For a number of reasons, the overlap is rarely found in
homes. For one thing, there is a considerable amount
of work and cost involved in this kind of installation. It
also demands a lot of space.
The Virgin Atlantic Upper Class Lounge shown here
takes the technique to another level. ‘We have to credit
the architect, who clearly had some kind of vision for
this layering and giving some ambiguity to the ceiling,’
says James. ‘You really don’t read that as a ceiling, you
read it as a much more dynamic part of the space.’
An important consideration is the viewing angle: it is
critical not to reveal the source. ‘You want to consider
your viewing angles carefully – particularly if you’re
dealing with multiple layers in a more complex space
with stairs and landings at different levels,’ says James.
The diagram shows a deep slot, which in effect
conceals the lamps, but upstands or baffles would also
restrict the view of the light source. Surface finishes,
too, must be chosen carefully, so the light sources are
not revealed by reflection.
But the overlap should be used carefully. ‘It’s a
technique that really says something quite strong in a
space,’ says James.
Above: At the Virgin Atlantic
Upper Class Lounge at London
Heathrow Airport, the overlap
adds ambiguity to the ceiling,
and it reads as a dynamic part
of the space. The scheme is by
Isometrix Lighting + Design and
the architect is Softroom
Opposite: Light sources must
be installed out of sight, or
upstands and baffles can be used
to hide them