Case Study:Preventing an Unthinkable Health and Safety Incident

Following our work at the Royal Earlswood site, we were recommended to the property management company First Port. For this project, the client required stone cleaning and render cleaning services at a residential block and Grade II listed building in Redhill, London.

Discover how our specialist team completed phase one with cleaning, repair, and testing across the stone and specific render substrates while helping our client avoid a health and safety disaster. 

The Logistics

After receiving the call from First Port to restore the façade of their Grade II listed residential property, one of our specialist stone cleaning technicians visited the site to discuss with a surveyor and devise a strategy for the work.

During the pre-site assessment, we noticed the following issues:

• A stone repair and colour match were required, meaning we would first clean the building and send a sample substrate for the correct colour match.
• Although the wall looked like stone from the outside, some substrate was a render material which would need alternative cleaning and repair techniques.
• Access would require combining our patented steam cleaning pole equipment and elevated access via a cherry picker.

Spectrum achieved the tender due to our pricing, experience, and specialised stone cleaning and restoration techniques we have exhibited across numerous other stonework projects across London. Our previous experience and a recommendation from another client assured First Port.

We also conducted a sample clean to demonstrate that our superior stone cleaning capabilities were worth the investment. The results of this sample service satisfied the client, and we booked a time and date for the real work to commence.

The Project

With our pre-site assessment finished and a clear strategy for our stone cleaning and render cleaning services in place, we began the initial cleaning before any repair work could follow.

In our experience, cleaning a façade reveals other defects not found by initial inspections. The property had received no maintenance since 2000. It had significant staining across the stone and loose render causing concerning health and safety issues.

After cleaning, we conducted a tap test to locate loose render and ensure the residents' health and safety remained accounted for.

We used our patented steam-cleaning pole system to clean all areas of the building. This specialist process unique to Spectrum allowed us to work without proximity issues and use an elevated work platform for the more challenging areas.

Because the terrain to access the clock tower was garden grassland, we used the lightest machine possible to avoid spoiling the area and any potential danger caused in case the heavy machine sunk into the moist conditions. This precaution demands a specialist whose knowledge of the risks associated with certain machine weights in operation on grassed areas is paramount for health and safety.

After cleaning the property, we could assess more defects for repair and colour matching. As a bonus, we offered sampled repair work across some rendered material to be sent to a lab to secure the correct colour match.

Finally, we carried out a tap test to reveal any hidden issues, such as loose render and stone removal, before the tender for the stone repair work required for phase two of the project could commence. 

The Site

Phase one of the Royal Earlswood and Edwards House was in Redhill, London. With over 3645 square meters, the residential block consisted of four floors and a clock tower requiring cherry picker access.

The Grade II listed building built in the 1860s once housed the former workshops and laundry for the Victoria Court Hospital and Asylum. Built with brick and featuring additional stone embellishments, the previous structure had ventilation openings within the façade.

As with all Grade II listed buildings, all work must remain sensitive to the property's unique character and historical character.

However, when the building was converted into apartments, they filled the ventilation openings with brick to create a smooth finish before using cement render over the top - to replicate the stone. 

Unfortunately, cement render can cause breathability issues for the bricks beneath, as any moisture within cannot escape. This issue ultimately causes delamination due to the liquid caught in the wall freezing, expanding, and pushing the render away from the substrate.

Challenges

This project came with a handful of challenges. But with every stone cleaning project, the main priority is to conduct the stone and render cleaning services safely and effectively by ensuring the correct access methods are in place.

The gardens and the clock tower had the most difficult access. For the clock tower, we required an elevated work platform to operate in the garden. Due to this weight, we liaised with a specialist surveyor who recommended the lightest version of the machine possible to avoid damage and remain safe.

But even the lightest cherry picker available to reach 27 meters still weighed 3.5 tonnes, so we had to be careful that the terrain offered a strong enough foundation for work to proceed.

Another challenge with stone repair work is that the full extent of the issue is only 100% clear once you have thoroughly cleaned the building. That's why cleaning the building is integral to uncovering any potential issues.

On this occasion, cleaning revealed alarming health and safety issues with loose chunks of render due to delamination. Ensuring no more hidden health and safety issues presented themselves and potentially harmed any of the residents, we conducted a routine tap test after completing the cleaning.

After repairing the defects and damaged render, the next challenge was to find the correct colour match for the stone works. Due to the Grade II listed tradition of the building, finding the colour match was essential to uphold its historical reputation.

Throughout everything, the budget was considered, which meant we had to prioritise the repair work to remain safe without overstretching our resources and allotted timeline. 

The Result

Our expert team improved the appearance and stability of their Grade II listed building without any significant alteration. The client was satisfied with our stone and render cleaning and repair services.

Here is a final overview of our process:
A pre-site visit and survey of the building enabled us to create a solid strategy to complete the stoneworks safely and successfully. We used photographic reporting while cleaning to highlight all the areas requiring repair for future reference.

Our patented pole equipment allowed full access to the property alongside a cherry picker for the bell tower and fourth-floor areas.

Using our unique patented cleaning equipment, we cleaned the stone and rendered surfaces in line with our high-quality industry standards.

A final tap test displayed further hidden de-bonded areas of the render that posed a risk of the render falling from the building. The team removed areas of a delaminated and damaged render without going over budget.

After sending samples to the lab for the team to recreate, we found the correct colour match for the stonework.

Despite the challenges, we were happy with the outcome of our stone cleaning and repair services. It's put us in a great position to start phase two of the cleaning process.

Have you got a project in mind? Contact us today for more information about our stone cleaning and restoration services.