Following the completion of previous work, we were called in to quote for a full clean of the render to Blackwell Farm, located at the University of Surrey.
The client required the removal of green algae which had built-up across all sides of the building, with the north-facing side having seen particularly extensive growth. This is not an unusual growth pattern for algae to take, as north facing sides of a building tend to naturally suffer more from damp – the biggest factor in algae growth.
The garage walls and patio area also required moss and algae removal, along with exterior window cleaning and the cleaning out of all gutters.
The client was looking to utilise the Blackwell Farm property for future accommodation for visiting dignitaries and wanted a result that created the right impression of the university.
We had to find a solution that could effectively remove the algae without risking damage to the render – in terms of abrasion, pressure and saturation.
Algae growth on render is hugely unsightly, but luckily, it’s unlikely to cause any significant damage. However, if left untreated, it will only continue to get worse and can continue to spread further across the building. The wind can blow algae spores further afield, and unlike other plants, algae do not have roots or leaves, allowing them to grow on almost any surface. As the algae grows and contracts, it also has the potential to cause superficial cracking to the render, decreasing the building’s aesthetic appeal even more.
Finding a solution that avoided saturation of the substrate was vital. Excess water can become trapped or can take a long period of time to dry out, leading to other issues further down the road. Any excess moisture on the surface had the potential of exacerbating the growth of algae.
After conducting a full site survey, we decided to complete the work using the DOFF system by Stonehealth. DOFF is a high-temperature, low-pressure system which utilises a low volume of water as to not saturate the substrate, allowing it to dry within minutes.
Working with the client to ensure minimal inconvenience and disruption, we programmed the works in, estimating five days for completion.
Also included in the brief was window cleaning (which included exterior windows) and a full gutter clean. A blocked, overspilling gutter can be a contributing factor or the cause of algae growth.
The Technical Part
The completed Risk Assessments and Method Statements were reviewed before work commenced, particularly as the project required working at heights from towers and the use of a mobile elevated work platform.
Our Stonehealth accredited and IPAF trained operators completed the clean using the DOFF system; a system that utilises superheated water at low pressures to effectively remove moss, algae and other biological matter from even the most delicate of surfaces and masonry.
Render can be significantly damaged when incorrectly cleaned, or cleaned by those without knowledge and experience of the material. Not only is it susceptible to abrasive and pressure damage, if too much water is used in the clean, it can penetrate the material, causing saturation. This excess water can take a long period of time to dry out and during cold weather, it can freeze. Subsequently, this can cause the render to crack – causing costly repairs or even the need for replacement.
Even with the challenges we faced, we were able to complete the work slightly ahead of the planned programme time.
The Technology and Equipment
DOFF System – by Stonehealth
Using high-temperatures but low-pressures makes the DOFF system by Stonehealth perfect for carrying out cleans to delicate building materials such as render.
Its low water volumes (3 – 5 litres per minute) means that deep penetration and saturation of the surface is avoided. The materials usually dry out within a matter of minutes. And because of this, it means that the DOFF can be used internally, with careful planning.
Environmentally friendly, the DOFF system does not require chemicals. Impressive results are achieved with water and steam alone. This mitigates the risk of potential chemical reactions with the substrate and means that it’s safe to use within the vicinity of pre-established ecosystems.
The DOFF system is hugely versatile. The operator can fully adjust the temperature and pressure, allowing for the perfect combination for each individual scenario.
Ideal Response are approved operators of Stonehealth systems. This means that we have received full training on the equipment and that we are using genuine Stonehealth products. It also means that we meet set standards to help protect customers and their buildings.
Avoid pressure damage, deep penetration and thermal shock to your render by trusting Ideal Response to effectively remove algae and moss from your building.