FLOORS & FLOOR COVERINGS
Modern underfloor heating systems
represent the height of luxury,
comfort and convenience for
modern dwellings and are a standard
specification for higher end properties. But this
isn’t a new approach to heating rooms; indeed
the earliest evidence of underfloor heating can be
traced back some 7,000 years when trenches cut
into floors covered with stone carried warmth from
strategically placed fires.
Clearly a great deal has changed since those
early days and there have been a number of major
developments in the last 100 years that have
resulted in the modern systems we know and enjoy
today. But more recently, the most significant
development in underfloor heating has to be the
introduction of flowing liquid gypsum screeds.
Superior in many ways to the more traditional sand
and cement-based screeds, liquid gypsum screeds
offer many benefits including cost, convenience
But arguably, the biggest advantage of a flowing
liquid gypsum screed is that it can be force dried
quickly and safely, provided the right equipment
is used and best practice is observed. Force drying
is suitable for these screeds as they do not curl and
BUILDING PRODUCTS | FEBRUARY
Ross Verity, managing director, ForceDry, explores the advantages
of flowing liquid gypsum screeds over sand and cement options and
explains why flowing gypsum screeds and the latest force drying
technology are a winning combination.
they need no reinforcement. In addition, shrinkage
is extremely low and large bays can be laid without
risk of cracking.
Screed drying times holding up projects are a big
issue for contractors. Site running costs and penalty
clauses for projects running over time can run
into many hundreds of thousands of pounds and
the associated uncertainty is a major problem for
project managers trying to plan work schedules.
The drying times given on screed datasheets
are generally based on a fixed environment, at
20ºC and 60% relative humidity throughout
the stated drying period. But it is rarely, if ever,
possible to achieve these conditions naturally
on a construction site in the UK. Typically an
anhydrite (what gypsum becomes when heated)
screed, installed at 50mm depth, will be said to
have a drying time of 60 days, given these fixed
environment conditions, but on a construction site
this will often extend to 90 days or more.
The force drying technique can bring the total
drying and commissioning time down to just 28
days. The key to successful force drying is using the
correct specialist drying equipment, total control
of the environment (including temperature and
humidity) and appropriate moisture testing.
These factors ensure that the necessary heating
and cooling programme can be carried out with
absolute accuracy in terms of results and timing.
Furthermore, using this force drying process
reduces the risk of floor failure and the associated
expensive remedial costs.
Time is money in construction, so being able
to shave up to around two months off installation
and commissioning time for liquid screed floors by
force drying represents a very significant cost saving
for contractors and developers alike, and brings
welcome certainty to any construction programme.
While force drying is often employed as an
afterthought once it becomes clear that the reality