We were contacted by the client regarding the cleaning of the stone detailing and stone window cills to the front facade of the building which overlooks Romford Market. In addition to this, we were also instructed to complete the cleaning of the stone steps which lead from St Edwards Way.
The property in question is a commercial building with private flats on the upper levels. Constructed from brick, it faces Romford Open Market and boasts flat stone cladding, stone detailing, and stone window cills to the front.
At ten years old, the stone detailing and cills have become black and dirty over time through algae build up, microbial growth, and pollution. We were instructed to clean the stone detailing and cills to remove this build up, without the use of chemicals.
However, because access to the shops could not be interrupted, work could only be carried out to the building after 5pm. And because private flats are situated on the upper levels of the building, work had to finish by 9pm, leaving us a four-hour window.
With regards to the cleaning of the steps, it was decided that these could be cleaned during normal working hours due to the fact that they could be sectioned off to allow access along one side while the other side is cordoned off to complete works.
Scaffolding towers would be required for both access to the balcony above the market entrance, and to grant access to the rear of the entrance. Work was estimated to take two days for the cleaning of the steps, and 2-3 days for the cleaning of the stone detailing and cills.
The Technical Part
Using the industry-leading DOFF technology, the clean was designed to remove algae, dirt and pollution on the stone. However, any discolouring due to internal contamination or natural features of the material would not be removed.
As a steam-based cleaning method, the DOFF required no use of a chemical biocide during the course of treatment – a requirement stipulated by the client. This absence of chemicals not only makes the DOFF environmentally friendly, but makes it safe for use on a variety of materials and buildings, including delicate masonry and heritage buildings.
During the clean, our technicians were able to fully control the temperature of the steam, allowing adjustments to be made as necessary when combating the different types of contaminants present. The temperature at the nozzle end of the DOFF can reach temperatures of up to 150°C.
By using high-temperature steam and low pressure to the surfaces being cleaned means that saturation of the stone was avoided. Subsequently, the surfaces dried within a matter of minutes. The DOFF was used to clean the stone detailing and the steps.
No power was available on the market side, only water from a bib tap in the loading bay. Therefore, a bowser was used for water storage to clean this particular facade. Once cleaned, a biocide was applied to the stonework to help prevent algae regrowth.