Issue 47 JUNE - Flipbook - Page 56
How to clean
your building?
Mark Styles, Managing Director of Thomann-Hanry® the façade cleaning experts, offers an expert
opinion on the different methods of cleaning the facades of historic and listed buildings.
Historic and listed buildings facade cleaning
Historic and listed buildings, no matter the size, have
become a key record of the expressions of culture across
time within the built environment. The need to maintain
and preserve these structures is crucial to ensure they can
be enjoyed by future generations.
While interiors are normally the first thought, when it
comes to upkeep and preservation, the building’s façade
is an area which will also need regular, specialist conservation and cleaning to prevent the expense and inconvenience of major structural work as the result of neglect
and decay.
Why clean?
The modern urban environment in which many historic
and listed buildings are situated, are havens of dirt and
grime, much of which, while perceived a benign, can, over
time, cause significant discolouration and surface damage
to the façade’s substrate. Even in more rural areas, long
term build-up of biofilm (a thin layer of algae and
phytobacteria) and water damage can be just as harmful.
Regular cleaning and maintenance checks can spot areas
of concern and quickly remedy them before they turn into
more structural, time-consuming, and most importantly
costly problems.
Below, facade cleaning The Ritz Hotel, Piccadilly, London.
Which method is right for your building?
Before you undertake any façade cleaning, you will need
to understand the structure and materials which are used
on your building’s façade. This simple starting point will
allow you to form a considered approach to the types of
cleaning which can be undertaken for your historic or
listed building. Using the wrong method, can cause both
short- and long-term problems which can add unexpected
time and cost considerations.
Methods of cleaning
With historic and listed buildings, the cleaning methods
used to maintain the building’s façade has several
constraints which will need to be considered. The most
important is that the cleaning technique must not cause
direct or indirect harm to the building’s surface. Any
cleaning method used should also preserve any masonry
patina, not deposit or generate by-products which affect
future preservation works, and the method should not
initiate new decay processes or exacerbate old ones.
Wet cleaning methods
There are three main water-based options when looking
at cleaning the façade of a historic or listed building,
systems which use water at variable pressures with high
temperature such as DOFF, systems which use water and
abrasives at a low pressure such as TORC, and systems
which use constant water misting.
