Benson House Case Study

The brief

Benson House is a Liquid Waterproofing Awards 2019 winning refurbishment project situated in the city centre of Leeds. The client, DLG Architects, required landscaping around the site to transform the existing podium car park into a landscaped deck, and a new scheme to compliment the updated entrance.

Bauder Building Board

Project: Benson House
Location: Leeds
Project Type: Refurbishment
Roof Area: 1500m²​
Specifier: DLG Architects
Approved Contractor: Protech Roofing Ltd

The systems

Bauder’s hot melt structural waterproofing system was specified because it is ideally suited as a waterproofing system beneath paved or ballasted surfacing, car parks, podiums, plazas, green roofs and substructures. Our hot melt system provides a monolithic, fully bonded waterproofing membrane that is tough, flexible and self-healing to minor punctures.
Bauder’s lightweight intensive substrate with turf was also installed to provide valuable recreational space to the podium car park. The turf was bespoke to the project and together with the intensive substrate helps with storm water management, with the drainage layer and substrate keeping the system weight to a minimum.


The existing slab was not level, and so prior to beginning the waterproofing installation, Approved Contractors, Protech Roofing Ltd, had to flood the slab with hot melt to level the surface. As this was a refurbishment project, the installers had existing planters and upstand details to overlay. The outlets also had to be replaced and the system fully sealed. Access to the rest of the site for other trades was through the main working ground. Being in the city centre of Leeds, the site access was also rather restricting.


To solve these challenges, the waterproofing was tested and repaired continuously with the results reported back to the client to keep them informed. The contractors arrived to site early in the morning to avoid rush hour traffic and to minimise the impact on surrounding businesses.

Applied products

Bauder’s Hot Melt System

 This system has a BBA stated life expectancy to match the design life of the roof, bridges minor cracks and infills minor irregularities, and its full adhesion to deck restricts lateral water movement.
1 AP2 capping sheet AP2 Protection Membrane is a top quality, heavy duty, torch-applied, SBS elastomeric bitumen capping sheet. The product features chemically treated bitumen to deliver superior root resistance which has been tested and approved by the FLL
Bakor 790-11 hot melt Bakor 790-11 hot melt is an environmentally friendly, hot applied, rubberised bitumen formulated to provide a monolithic fully bonded roofing and waterproofing membrane. It is a hot poured fabric reinforced application.
3  Deck Primed concrete.

Turfed intensive green roof system

Bauder’s turfed intensive green roof system is very environmentally friendly, with the substrate including a high proportion of recycled crushed brick and aggregate, the protection, filtration and isolation layers manufactured from recycled materials, and the DSE40 water storage and drainage layer manufactured from recycled polyethylene.
Intensive substrate and turf​ This FLL/GRO compliant substrate provides a free draining, growing medium for green roof systems. It is a lightweight substrate designed for most vegetation and provides aeration qualities with some inherent water retention.
2  Filter fleece​ Bauder’s Filter fleece is designed to separate and contain Bauder substrates from the drainage element of the green roof system. It prevents fine material from being washed out of the substrate layer.
DSE 40​ Laid on to the completed waterproofing, in this case, Bauder hot melt, it provides continuous drainage within hard and soft landscaping. It is primarily used where the load is moderate to high, such as intensive green roofs like Benson House. Its compressive strength makes it suitable beneath paving laid on sand/cement or gravel bedding or within planter beds.
FSM 600​ Laid on the completed waterproofing to protect the completed waterproofing from mechanical damage.
PE foil​ Fitted directly on to the completed waterproofing to separate the landscaping from the waterproofing.