The systems

The main roof area utilised the Bauder Total Green Roof System (BTGRS). This popular two-layer bitumen waterproofing system comprises SBS modified elastomeric underlayer and waterproofing cap sheet which gives superior performance. In this case, the Bauder Plant E capping sheet was used. This is proven to give long-term root resistance, protecting the roof and has been tested against the FLL’s stringent requirements. It was particularly important to protect the integrity of the waterproofing on the spa roof because of the potential for aggressive roots to damage the membrane.
 
The biodiverse element of the roof at South Lodge spa was supplied by Bauder’s native wildflower Blanket. This vegetation blanket contains a broad mix of British wildflowers which flourish depending on the geographical location of the project. In Horsham, some of the key species to establish were Oxeye Daisy, Bird’s-foot trefoil, Viper’s-bugloss and Yarrow.
 

Challenges

The unique deck of the new spa building presented a challenge to the installers fitting the green roof. With an incline of up to 24⁰ on one section of the plywood deck, the operatives needed a solution that would keep the substrate and vegetation in place. To overcome this challenge, timber struts were fixed to the plywood deck which were waterproofed to form a sound waterproof deck. Over this, a reservoir drainage board was laid and filled with biodiverse substrate. An additional trellis was braced against the struts sitting within the substrate to keep the biodiverse substrate in place. The contractors then laid the wildflower blanket and irrigation drip lines over the substrate.

Maintenance

To ensure safe access during the installation and after, for ongoing maintenance, a permanent fall arrest system was installed by Latchways.Bauder will continue to work with the hotel management team to maintain the roof. Post installation, Access Irrigation Ltd fitted a dripline irrigation system including a break tank pump and controller to regulate amounts of water distributed, removing the need for human intervention once set up. Bauder site technicians have carried out several inspections to ensure the roof is thriving. The view from the main hotel is now of a wildflower meadow featuring plant species native to the surrounding area.

 

Applied products

Bauder Total Green Roof System

BTGRS was selected for this project due the system being able to incorporate a special cap sheet that has been tested by the FLL to ensure long-term root resistance. It was also chosen for its longevity and heavy duty, robust qualities.

Bauder PLANT E cap sheet	5 mm root resistant, heavy duty, SBS modified elastomeric bitumen membrane featuring chemically treated bitumen to deliver superior root resistance. Perfect for use under a system which will need maintenance access after installation.
BauderTEC KSA DUO underlayer	3 mm thick technically advanced self-adhesive elastomeric bitumen underlayer with DUO lap technology and glass lattice reinforcement.
PIR FA-TE insulation 140mm	A rigid urethane foam insulation faced on both sides with aluminium foil. PIR FA-TE was used to provide lightweight, thermal insulation with a 140mm depth used to meet the required U-value.
DS1 DUO	A technically advanced self-adhesive SBS elastomeric bitumen underlayer with “DUO” lap technology to ensure thorough sealing of lap joints. This underlayer benefits from self-adhesive stripes which makes for a speedy installation.

Reservoir boards

Reservoir boards were used in favour of DSE for the drainage layer as they have a greater water capacity for the vegetation and the square compartments interlock to give greater stability to the structure.

Wildflower blanket

Lightweight extensive biodiverse green roof vegetation blanket providing instant greening of a roof with a mixture of 36 species of wildflower and 4 grass species. The blanket also has a coir carrier. Coir is made from coconut matting and is 100% biodegradable. Contact us to discuss your flat roof project