Rhondda Heritage Park

The Rhondda Heritage Park is a renowned tourist destination in South Wales, offering a glimpse into the coal mining community that thrived in the area for over 130 years until the early 1980s. Every year, thousands of visitors take a guided tour led by former colliery workers to experience the life of coal miners.

The Heritage Park takes great pride in its appearance and the local heritage it represents. However, the aging asphalt roof terraces that covered the old mine shafts had been leaking constantly, damaging the visual appeal of the visitor site.

The Challenge

The Polyroof technical team was called in to help with the waterproofing and refurbishment of the two roof terraces, measuring over 1100m², that protected the underground mining attraction. After conducting a thorough survey of the roof terrace areas, a customized specification was prepared. This specification included a comprehensive set of recommendations for addressing the issues that had caused the aged and worn condition of the terrace areas over the years. To support the proposal, additional information was provided to the client to demonstrate how a liquid system could seamlessly encase and waterproof the terraces while maintaining an aesthetically pleasing solution that was true to the authenticity of the site.

Satisfied that the solution proposed would provide the long-term peace of mind they were looking for, the Heritage Park awarded the contract to RM Polymers Ltd.

Before starting the work, any areas affected by fungal growth or moss were treated with Polykill Anti-Fungal Wash to eliminate all spores. Any holes in the asphalt were smoothed out or removed, and levelled using Polyroof Structural Repair Mortar. All large cracks and voids were cleaned and repaired using the same mortar.

PVC protrusions were removed and surfaces were cleaned with acetone. Any damaged, loose, or unsound concrete or brickwork was removed and repaired using Polyroof Structural Repair Mortar. All repairs were allowed to cure and dry before priming.

The Solution

One of the main features of the tourist attraction is the mining carts that were used to transport coal around the mine tunnels during its operation. Similar to train tracks, the mining cart tracks are fixed into the ground using metal bolts and fixings which over time had become a weak point for water ingress. Concrete and sandstone had been used as a “quick fix” to prevent rainwater entering the mine shaft below but a long-term solution was now needed. The cement and sandstone was carefully chiselled from the rails, exposing the original metal tracks which were then lifted and abraded back to their original condition. Whilst lifted, the underlying surface was made good before the application of the Protec System. Railway sleepers were then laid on a sacrificial layer on top of the waterproof membrane, upon which the tracks and mining carts were re-instated.

As the terraces are constantly trafficked by the general public, the client was clear that an anti-slip finish would be required on any walkway areas.

Following the application of the Protec System, Polyfinish and Quartz Sand Anti-Slip was applied to all walkway areas, to provide slip resistance and surface protection. A 50mm margin around the perimeters of the terrace was masked off to provide a neat termination of the anti-slip finish. Ensure masking tape was removed whilst resin was still wet. Then a third coat of Protec Resin was applied at a minimum coverage rate of 0.5Litres/m² (2.0m²/Litre) and whilst wet, clean dried quartz sand (0.7 – 12mm) was broadcast at an approximate coverage rate of 4.0kg/m². Once cured, the loose sand was removed.

Workmanship

The engine houses along the tour experience featured vast amounts of intricate details and unique items and structures, such as “Bertie and Trefor” – the names given by the mine owner to the mine head stock wheels. This presented an exceptional challenge, particularly in regards to the difficulty of working on the intricate details of the degraded mastic asphalt upstands and decking.

As a result of many years of weathering and gravity, the vertical sections of asphalt on the raised terraced roof had slumped and rippled, leading to stress cracks and ultimately water ingress. To overcome this ugly problem, the asphalt was stripped from these vertical sections back to the concrete and removed from site in accordance with the Health and Safety policies in place. The contractor then installed new 18mm OSB3 to these areas to create a flat substrate for the Protec System. The incorporation of Polyroof pre-formed GRP Drip trims at the bottom of the OSB3 ensured the timber would not be exposed to any rain water in the future as well as provide a neat, edge detail.

To keep the overall aesthetic feel of the site, the application of the liquid waterproofing system at wall abutments was critical. This, combined with the undulating nature of the stone and brickwork meant that the contractor would not be able to install a cover flashing or termination bar.

Instead, the contractor carefully dressed the system onto the wall to the standard minimum 150mm upstand height and into a chase.

The edging was then finished with a mortar to provide a neat and clean weatherproof finish, in-keeping with the traditional methods of the site at the time of its construction.

The roof terraces that cover the old mining areas also act as the main walkways to the Heritage Centre’s tour routes. Therefore, one of the main challenges of the project was the complex planning of the works to ensure that the site continued to operate so not to financially impact the heritage park. It was imperative that works were complete within an 8-week period with 17,500 visitors booked in for their annual Santa’s Grotto Experience Tour beginning in early December.

The application speed of the catalyst cured Protec System, combined with communication between the contractor and the site to ensure unobtrusive installation, meant the centre stayed open and the tours running with minimum disruption.

The benefits of using a fast-curing liquid waterproofing solution were also vital due to the ever-changing micro-climate in the Welsh valleys. On any single day, the weather would serve up anything from bright sunshine to windy, rainy conditions. Therefore, the fast-curing Protec System, combined with the flexibility of the installation team, who gave up weekends when required, ensured the project was finished on schedule. The works were completed to an extremely high standard with full encapsulation of the roof terrace areas and without a single detail being left exposed to the elements.

Conclusion

The unique aspects of this project certainly kept the team on their toes. But they were determined to complete the project on time.

The team worked tirelessly, even giving up their weekends to ensure that the project was completed on schedule. Despite the harsh Welsh weather, they pushed on and were determined to make sure that Santa could visit the children of the Welsh Valleys. It was a challenging project but the team’s hard work and dedication paid off.

Finally, the project was completed and the results were astounding. The roof terraces are now fully waterproofed and refurbished, and the visual appearance of the visitor site was greatly improved. It was a project that was both memorable and rewarding to all those involved.