The most noticeable aspects of building conservation work are the cleaning of masonry façades, whether of stones, brick or terrracotta. If not performed properly, it has the potential to cause harm either immediately during purification or for a time after the completion of the restoration work.
Unfortunately there are still enough evidence of damage caused by the improper removal of dirt and blemishes that will continue to weaken our constructed heritage to those who are unskilled and inexperienced.
This article is not where you can find answers to all the difficulties presented by masonry cleaning (and you will not find them on the patented cleaning material label). The aim is to raise awareness that, as with all heritage conservation, problems can only be overcome if suitably trained and qualified experts examine, define and test them carefully.
IS MASONRY CLEANING NECESSARY?
Core questions should be answered in order to satisfy all concerned before any cleaning takes place. The biggest one is obviously: why clean? This means: will the building benefit from cleaning and is it appropriate, more importantly?
While proper maintenance can keep the building free from dirt accumulation, natural weathering is allowed, while the abrasive or corrosive effects of various methods of cleaning can remove or kill the protective surface which can develop on the building, which results in an unsurprised situation where it has not been cleaned. This is not just the case after you clean the car: decay agents and soiling may be attacked and foundations on a freshly cleaned surface much easier than on a surface with its own dirt set, which is clearly seen by the quick loss of the pristine surface.
The response the entrepreneur might suggest is to add a ‘protective’ layer. False reply! Any protective finish to change the surface’s moisture and pollution absorption will also influence the way in which moisture is emitted. The results can be difficult, but all coatings should be avoided for this purpose alone.
