Case Study:Expert Stone Column Restoration at Providence Square

Introduction

This high-end residential property in Central London close to Tower Bridge required various building maintenance services, including façade cleaning, timber repairs/replacement and painting across multiple properties and substrates, including stone, brick, metal, and wood.

On our most recent visit, we addressed an issue with its stone columns, which had become stained at ground level by dog urine. To tackle this problem, Spectrum Specialist Support was enlisted to restore the stone columns using DOFF and TORC cleaning methods, as well as advanced specialist colour coatings to conceal the staining.

The Logistics

When attending the site to complete other maintenance and repair work, we noticed this area of severe staining and concluded the following methods would be our best course of action.

• We would use DOFF cleaning to remove superficial layers of dirt and organic staining from the stone columns using high-temperature, low-pressure steam.

• The TORC system could address deeper, more stubborn stains, ensuring a thorough cleaning with its gentle swirling vortex of water, air, and fine granulate.

• If these two treatments were unsuccessful in any areas, specialised colour treatments could be applied to conceal residual staining and protect the stone from future damage, ensuring long-lasting results and maintaining aesthetic consistency.

To effectively clean and restore the stone columns, our team used several pieces of specialist equipment. The DOFF system, which uses superheated steam at low pressure, was ideal for removing organic matter and stains without damaging the stone. The TORC system, known for its gentle swirling vortex of water, air, and fine granulate, was used for targeted deeper cleaning to address the more stubborn stains. Additionally, our team applied specialist coatings to conceal and protect the stone from future staining.

The Project

This stone restoration project in Bermondsey involved a thorough cleaning process using both the DOFF and TORC systems. Initially, the DOFF cleaning system was used to remove the superficial layers of dirt and organic staining from the stone columns. The high-temperature steam effectively removed most of the dog urine stains while preserving the integrity of the stone surface below. Following this, the TORC system was deployed to address any remaining deeper stains, ensuring a thorough cleaning. This piece of expert equipment, along with our team’s insight into knowing when to use it, was how they managed to achieve the results our clients were desperate for.

In addition to the cleaning, our team also focused on stone colour matching to ensure that the columns' appearance was consistent and aesthetically pleasing for the residents. Specialist coatings were applied not only to conceal any residual staining but also to protect the stone from future damage, thus extending the life of the restoration work.

The coatings we used were Keim's Lasur products which are unlike any other product we have seen on the market, they are more of a wash than a paint. The micro-crystalline nature of the Keim coating creates finite spaces between crystals, which are large enough to allow vapour to pass through, but small enough to prevent water and staining ingress. This high breathability allows moisture in the building to be released quickly, avoiding moisture buildup between the coating and substrate. This ultimately prevents damage to the surface and columns due to trapped internal moisture.

The process involves a first coating with Keim Restauro Fixativ, which penetrates the stone substrate but does not fill the pores. After 24 hours, a second coat, which is the colour-matched coating, is applied. To create a seamless blend we like to dilute the pigment with Keim Restauro Fixativ in various dilutions that replicate the original substrate colour. In this case, the dilution was 4:1, the perfect translucence and opacity, resulting in the final appearance of the stone not seeming that it had been coated.

In most cases, the dilution of the pigment is a trial and error process until the desired result is achieved. This means starting with a high dilution and if necessary re-coating with a lower dilution to achieve the correct appearance. While we are using this product for stain masking purposes, this product is also exceptionally well suited to masking stone, brick and concrete repairs, which will then make the surface consistent and homogenous.v

The Site

Providence Square is a large residential complex in Bermondsey that required careful planning and coordination to minimise disruption to residents. The property is in an affluent area of Central London, housing hundreds of residents within high-end apartments across 11-12 buildings close to Tower Bridge. Two facades are waterfront, with the highest aspect of the residential property being ten storeys tall.

In high cost of living in areas like these, residents and clients expect the highest service standards across every aspect of building maintenance we provide. The development and property management have created a peaceful and relaxing environment for the tenants on the waterfront, which we maintained while on-site.

Challenges

One of the main challenges faced during the project was the stubborn staining at the base of the stone colours, which required multiple cleaning passes with both the DOFF and TORC systems. Additionally, ensuring that the colour matching of the stone was flawless presented another challenge, as it required a keen eye for detail and expertise in stone restoration techniques.

Conclusion

The restoration of the stone columns at Providence Square was a project that showcased Spectrum Specialist Support’s expertise in stone cleaning and restoration. By employing advanced DOFF and TORC cleaning systems and applying specialist coatings, we were able to effectively remove the stains and protect the stone surfaces for years to come. 

The success of this project underscores why Spectrum Specialist Support is the right choice for complex restoration tasks, combining technical expertise with innovative solutions to deliver exceptional results.