W
ith today’s requirements for
faster installation of tiling and
the use of more demanding
substrates, ‘uncoupling’ matting and
membrane are being used more frequently
and in some cases are a necessity.
Uncoupling principles have actually
existed for centuries, with the Romans
being the first documented users of the
building process, which incorporated an
“uncoupling” method.
These early practices used a mud bed to
separate the substrate (then a two-inch
thick layer of packed and flattened sand
and cement) and the tiles. Both systems
use the separating layer to provide an
uncoupling buffer between the tile and the
substrate, enabling the substrate to move
independently to the tiles.
Modern uncoupling system methods have
improved dramatically, but the same basic
principles still apply for today’s uncoupling
mat systems, which are now in common use
on floor tiling installations onto a variety of
different substrates.
Coming in many forms, from thin,
lightweight matting, to traditional cavity
mat and floating systems, they give
architects and contractors peace of mind
when designing floor tiling installations.
Designed to provide a buffer layer when
tiling onto floors, they protect against a
variety of problems that can cause tiles to
crack or de-bond.
One common problem is the potential for
the substrate to contract or expand. In
particular, newly laid sand: cement screeds
or concrete may contain large amount of
moisture, which as evaporates, causes the
screed to shrink.
However, all substrates will expand and
contract naturally due to humidity and/or
temperature fluctuation, and this is
especially true where under floor or
under-tile heating has been installed. What’s
more, certain water-sensitive substrates,
such as anhydrite screeds (or calcium
sulphate) will lose their cohesive strength if
they get wet.
Wood is a hygroscopic material, and this,
therefore, increases the potential risk of
dimensional changes occurring within
boards due to moisture expansion and
drying shrinkage movement, resulting in
lateral movement stress being generated
between the board background and the
rigid ceramic tile finish.
Any movement, whether shrinkage or
expansion, can cause stress cracks that can
transfer through to the tiled surface,
causing the tile to either fracture, or
de-bond from the background. Uncoupling
matting helps to prevent these lateral
stresses from transferring through to the
tiled layer, by absorbing these stresses and
transferring them evenly over the floor.
Matting also has the ability to bridge
static cracks i.e. shrinkage cracks up to
2 mm wide and joints between sheet &
board backgrounds.
Another of benefit of modern matting
systems is their suitability forDavid Wilson of BAL takes a look at why specifying an
uncoupling system is a sensible option for making a floor
tiling installation as efficient as possible
Conscious uncoupling
Coming in many forms,
from thin, lightweight
matting to traditional cavity
mat and floating systems,
they give architects and
contractors peace of mind
when designing floor tiling
installationsSTRUCTURAL ELEMENTS 49ADF JUNE 2019 WWW.ARCHITECTSDATAFILE.CO.UK