The project

Lagg Distillery, located on the Isle of Arran in Scotland, is a new build whiskey distillery which opened its doors to the public for the first time in the autumn of 2019.

The brief

The client was eager to create an iconic landmark and echo the contours of Arran with a roof scape that would blend into the environment. In order to ensure all expectations were met, Bauder worked closely with the architect, Denham Benn, during the design and specification of the project.

A metal roof deck laid on steelwork formed the structure that would incorporate a warm roof build-up with a lightweight sedum green roof finish to resonate with the landscape and withstand the prevailing winds.

Bauder Building Board

Project name: Lagg Distillery
Project type: New build
Location: Isle of Arran, Scotland
Roof size: 2700m²​
Building owner: Quantum Solutions 
Specifier: Denham Benn
Approved Contractor: Greenroof Ltd

The systems

 To meet the project brief, Bauder’s technical team designed a roof solution  combining Bauder Total Green Roof System (BTGRS), our high quality bituminous system, and XF301 sedum blanket, our most lightweight integrated green roof system.
BTGRS is a durable, root-resistant bituminous waterproofing solution for use with landscaping. The system uses SBS modified elastomeric membranes for superior performance and unrivalled reliability,  The PlantE capping sheetis tested by the FLL and proven to give long-term root resistance. The system is suitable for all types of green roof landscaping options. The roof is covered with the comprehensive Bauder guarantee for product, workmanship and design.
Bauder’s XF301 lightweight sedum system, which comprises a mix of over 14 species, is laid directly onto the BTGRS waterproofing without the need for further drainage and substrate layers. The XF301 system contains a moisture mat which retains up to 5 Ltr of water/m2, helping to retain water for the plants in pitched roof scenario.


The shapes of the roofs, are complex,rising from 2 meters above ground level to 12 meters, the width of the roofs varying from 16 meters to 40 meters, and gradients ranging from 8 degrees to 31 degrees. On the steeply pitched roofs, the insulation and waterproofing is supported by mechanically fixed battens, these carry the weight of the system over the extreme slopes.
The building is perched on cliffs close to the Atlantic Ocean which face prolonged storms and gale force winds for many weeks a year. A unique sedum restraint system consisting of stainless steel retention strips and aluminium edge trims were fixed to the roof to hold the system in place and prevent wind uplift and slippage of the blanket. Due to restrictions with ferries, a delivery system had to be implemented that first saw materials to a holding place on the mainland, then meet the designated ferry to the island before finally being hoisted by crane to the roof.

Working in such an environment called for maximum focus on safety during the installation. A system of abseiling pulleys and fall arrest systems were set up on the sloped roofs together with wind monitoring and on-site instruction.
On completion of the works a permanent Latchways fall arrest system was installed. An irrigation system has also been commissioned complete with break tanks, pump, pipework and controller in order to provide a water feed to the sedum in times of drought to ensure the health of the living vegetation.

Testimony and Recognition

Greenroof UK were awarded green roof project trophy for their workmanship on the inspiring Lagg Whiskey Distillery and Visitor Centre on the Isle of Arran. The finished roof emulates the look of a rolling hillside and cuts an impressive view against the backdrop of the Firth of Clyde.

Scott Dean, managing director at Greenroof UK Ltd, commented: “This project pushed the boundaries in terms of installation, logistics and environment; therefore, it is a tremendous accolade to have won this award which acknowledges the contribution of everyone involved”

Applied Products

Bauder Total Green Roof System

BTGRS was specified for this project due to the systems’ 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.


1 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 which has been tested and approved by the FLL, perfect to use underneath a sedum blanket like that of Lagg Distillery.  
2 BauderTEC KSA DUO underlayer 3 mm thick technically advanced self-adhesive elastomeric bitumen underlayer with DUO lap technology and glass lattice reinforcement.
3 PIR FA-TE insulation 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 of 0.16W/m²K, on this specific project.
4 DS1 DUO A technically advanced self-adhesive SBS elastomeric bitumen underlayer with “DUO” lap technology to ensure thorough sealing of lap joints, even in lower temperatures like the Isle of Arran endures. The product features a glass lattice reinforcement for strength and stability, great for supporting the rest of the system used on this project.

XF301 Sedum Blanket

The green roof needed to be lightweight and low in height due to the varying gradients of the roof, which is why Bauder’s XF301 sedum system was selected.


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