More and more specifiers are taking into consideration the versatility and green credentials of waterproofing systems and considering mastic asphalt as a top deck waterproofing system for car parks, as well as for traditional roofs, bridges and other types of structural decks. Due to its longevity, low maintenance properties and skid resistance, mastic asphalt waterproofing systems are proving especially popular for retail applications.

Radflex Contract Services design and install waterproof structural expansion joints and work alongside mastic asphalt manufacturers to provide solutions for major retailers, shopping centres and car park owners UK-wide. The durability and flexibility of mastic asphalt waterproofing means the system works well with expansion joints, allowing for the natural movement of buildings.
The environmental credentials of mastic asphalt are also a key driver for its selection as a top deck car park waterproofing system. More than 10 years ago, the mastic asphalt sector became the first industry in the world to achieve the CarbonZero standard. It is carbon neutral – a bonus for any building owners or facilities managers anxious to show their sustainable principles and, when it has reached the end of its useful life, it can be recycled or used as a waterproofing screed, minimising the impact on the environment.

There are specially formulated mastic asphalt waterproofing and surfacing systems available for elevated vehicle decks, pedestrian walkways and access ramps, utilising advanced polymer technology for long-term durability, increased fatigue resistance, improved temperature stability and ease of installation. Several members of the Mastic Asphalt Council (MAC), as well as MAC itself, are members of the British Parking Association (BPA) and are experienced in solving problems associated with heavily used car parks.

Mastic asphalt waterproofing systems are delivered ready to lay, in 18-tonne hot charge tankers. This process ensures the mix is more consistent for a better quality, easier-to-lay asphalt. It also saves time, reduces costs and benefits the environment as there’s no secondary heating and melting needed on site; making it a much safer and quicker process. Systems are available that come with a 20-year warranty on car parks and are installed by trained, experienced asphalters.

One award-winning waterproofing project has been carried out at the Marks & Spencer store at Cheshire Oaks in Ellesmere Port. Opened in August 2012, the store was designed to be the most carbon efficient, premier M&S store to date with an architectural and design strategy that addresses several areas of sustainability at once. The second biggest M&S store in the world, and the largest ever built from scratch with over 148,000 sq ft of selling space over two floors, the single deck car park is connected to the store andwas protected with mastic asphalt waterproofing in conjunction with 96LM of Radflex S200 movement joint. It was declared winner of the ‘Best New Car Park’ at the British Parking Awards.

Mastic asphalt was selected for this project due to its green credentials and carbon neutral rating. The main contractor was Simons Group and the architect was Aukett Fitzroy Robinson. MAC manufacturer member IKO and Radflex Contract Services were involved in the construction of the 950-space car park. Radflex movement joints provided the best linkage available to support the performance of the asphalt.

The parking areas are permeable to allow for water harvesting and its south-facing elevation is covered in greenery to encourage wildlife diversity, with bird boxes installed where possible. The car park also provides electric car charging points and cycle parking for all store visitors. Hemp was used for insulation, all water from the car park deck was used to water the green walls, and all the timber used within the store was recycled.

Another Marks & Spencer project shortlisted for the British Parking Awards more recently was the M&S store in Matlock, Derbyshire. As part of a major store refurbishment, mastic asphalt was specified to refurbish the deck of the car park. The car park had previously been protected with mastic asphalt and it was stripped and re-laid by MAC member Rio Asphalt. All stripped off asphalt was recycled at the IKO plant in Matlock and the complete installation took just five weeks, with an average of 800m² mastic asphalt laid per week. In another impressive retail application, a mastic asphalt waterproofing project was carried out on the 11,000m2rooftop parking deck at the combined Waitrose Supermarket and John Lewis at Home store in Basingstoke.

Muse Developments, Basingstoke and Deane Borough Council’s regeneration partner, appointed Bowmer and Kirkland (B&K) for the Basing View business area, where the Waitrose/John Lewis store was built. B&K turned to Briggs Amasco initially to develop the plans for the car park into a viable scheme and subsequently to deliver the thermal insulation, lightweight concrete, and the mastic asphalt waterproofing and wearing courses on the roof deck parking area. Given the clients’ and tenants’ requirements, the proposed specification and finish meant that quality, user friendliness and longevity were all top priorities. Radflex installed 92LM of the S200 jointing system on the rooftop car park in mastic asphalt over a fully insulated deck.

As well as car park decks, mastic asphalt is also ideal for use on shopping centre service decks, and a system is available that incorporates aggregate broadcast into the pre-laid asphalt, ensuring a robust load-taking ability. This mastic asphalt system was recently used on a service deck at the Sainsbury’s Selly Oak superstore in Birmingham, in conjunction with the Radflex HD50 jointing system specially designed to withstand heavy loading from HGV vehicles.

This article featured in the April issue of RCi magazine – click here to view the publication online.