Bauder UK Native Plug Plant Biodiverse Green Roof System, Pitched Roof

Maximum slope:

25°.

Drainage layer:

- Bauder Reservoir Board Drainage and Protection Layer:

Water storage and multidirectional drainage layer. Used on roofs with 0–25° finished falls. Boards laid over the entire area to provide continuous drainage and increased water capacity for the vegetation.

Loose-laid (open cups up) onto the protection layer (or water flow-reducing layer, WFRL, on inverted roofs) over completed waterproofing, ensuring that the rebated boards are properly interlocked to provide adequate anchorage prior to the soil being laid. The board cups can be filled with water to provide temporary loading against wind uplift, prior to the remaining landscaping elements being installed, in accordance with the specification.

A parapet wall or restraint kerb should be provided to support the water storage/ drainage board at the base of the slope. This in turn will restrain and stabilize the landscaping against imposed shear load forces.

• Material: expanded polystyrene.

• Size: 0.795 x 1.298 m (rebates).

• Depth: 50 mm/ 75 mm.

• Coverage: 1 m².

• Water storage: 10/ 22.1 L.

• Compressive strength: 25/ 35 kN/m².

• Weight (saturated): 10.65/ 22.1 kN/m².

Filter layer:

- Bauder Filter Fleece:

Fine mesh polypropylene (PP) geotextile filter fleece, used to separate the growing medium from the vegetation barrier at perimeter abutments and around pipe protrusions, outlet inspection chambers, etc. Dressed up at all upstands and around all protrusions to be at least flush with the finished surface level. At abutments, the filter fleece must be extended by 500 mm beneath the reservoir board separate the vegetation/ drainage barrier and substrate growing medium, and then brought up between these two items.

• Material: polypropylene fleece.

• Weight (saturated): 0.125 kg/m².

• Pore size: 0.13 mm.

• Thickness: 1 mm.

• Roll size: 1 x 100 m/ 2 x 100 m.

• Coverage: 100 m² / 200 m².

• Water storage: none.

Substrate/ growing medium:

- Bauder Biodiverse Substrate (FLL-compliant):

Lightweight, free-draining substrate, designed as a growing medium for a range of different plant species. This FLL/ GRO-compliant substrate provides a free-draining growing medium for biodiverse green roof systems. Additionally, it provides aeration qualities, with some inherent water retention.

• Material: recycled crushed brick, expanded clay, shale, composted pine bark.

• Maximum weight (saturated): <1200 kg/m³.

• Typical supply weight: 950 kg/m³ (approximate).

• Water storage (by volume): 35%.

• pH value: 6–8.5.

Vegetation:

- Bauder UK Native Plug Plants:

British native plug plants, planted into the growing medium at a rate of 20 plants/m². The plant coverage rate should be increased to 25 plants/m² in areas subject to wind erosion (i.e. corner zones, ridges, perimeters, etc.).

• Size: 4 cm plugs/ 5–6 cm plugs.

• Saturated weight: 5 kg per tray (approximate).

Protection layer:

- Bauder Eco-Mat Protection Fleece:

Lightweight protection layer, constructed from recycled manmade fibres. Laid on the completed waterproofing to protect the completed waterproofing from damage (not required for inverted roofs).

Usually installed under the entire green roof area, but kept clear of all outlets and drainage trims. Eco-mat should be lapped by 150 mm at all joints. Loose-laid. Sufficient protection fleece must be allowed so that it may be installed to all abutment upstands and edge details, in accordance with Bauder instructions.

• Material: 100% recycled manmade fibre mix.

• Size: 2 x 30 m (w x l).

• Thickness: 6 mm.

• Coverage: 60 m².

• Weight (saturated): 3.8 kg/m².

- Bauder FSM 600 Protection Mat:

Heavy-duty protection layer constructed from polyester and polypropylene fibres. Laid on the completed waterproofing to protect the completed waterproofing from damage (not required for inverted roofs).

Usually installed under the entire green roof area, but kept clear of all outlets and drainage trims. FSM mats should be lapped by 150 mm at all joints. Loose-laid. Laps to be sealed by lightly heating overlap area with a propane gas torch/ hot air welding gun to melt the polypropylene fibres and then press-sealing the two fleece sheets together. Sufficient protection fleece must be allowed so that it may be installed to all abutment upstands and edge details, in accordance with Bauder instructions.

• Material: polyester and polypropylene fibre mix.

• Size: 2 x 30 m (w x l).

• Thickness: 4 mm.

• Coverage: 60 m².

• Weight (saturated): 3.6 kg/m².

- Bauder Pro-Mat Protection Mat:

Heavy-duty protection layer constructed from recycled, shredded tyres. Laid on the completed waterproofing to protect the completed waterproofing from damage (not required for inverted roofs; not for use with PVC waterproof membranes).

Usually installed under the entire green roof area, but kept clear of all outlets and drainage trims. Usually installed to provide access over waterproofing in heavily trafficked areas. Pro-mat should be lapped by 150 mm at all joints.

Loose-laid. Where landscaping installation is not imminent, loose laps should be taped with gaffer tape to eliminate the trip hazard. Sufficient protection fleece must be allowed so that it may be installed to all abutment upstands and edge details, in accordance with the Bauder instructions.

• Material: 100% recycled, shredded rubber.

• Size: 1.25 x 10 m (w x l).

• Thickness: 6 mm.

• Coverage: 12.5 m².

• Weight (saturated/ dry): 4.3 kg/m².

Biodiversity and habitat creation features (roof slopes of up to 10º only):

- Dead wood habitat:

Dead wood piles constructed from British native hardwood species (bark retained), ideally from trees removed locally or in the redevelopment works. Wood to be between 100 and 200 mm diameter and 600–1200 mm in length. 8–12 lengths per pile. To be stacked no more than 350 mm high, and to be secured in areas of high wind. One dead wood pile for every 50 m² of biodiverse roof. These provide rotten wood habitat as they decay in sheltered and shaded areas, as well as nesting habitat.

- Dew pools – wet areas:

Buglife-approved wetland feature, installed directly over the Bauder drainage/ water storage layer. To be buried so that the edges are level with the surface substrates. The plastic pond itself should be filled with substrate, which gradually slopes down to form a central hollow where water accumulates. One pool to be positioned for every 100 m² of roof area. Dew pools provide valuable wet, temporary ponds to provide breeding habitat and moist cavities.

- Insect habitat:

Buglife-approved insect hotel, fixed in position by placing the base plate underneath the underlying substrate. Preferably placed in a south-facing position, where it will receive maximum sunlight. The most exposed/ windy locations should be avoided.

- Sand piles:

Small areas of clean, sharp sand or builders’ ballast. Approximately 50–100 mm deep, covering areas of 2–3 m², left free from planting or seeding. These are situated in sunny areas with low substrate depths (80 mm). One sand pile for every 50 m² of biodiverse roof. These provide basking areas and ground-nesting habitat.

- Stone piles:

Small areas of clean, assorted stone in 1 m² sized areas, constructed from 20–200 mm diameter stone (ideally gathered from site), mounded in random piles no more than three stones deep. Approximately one pile for every 50 m² of biodiverse roof. These provide valuable shelter for ground-active invertebrates

- Undulating substrate:

Away from perimeters and doorways, the substrate can be undulated between 80 and 200 mm, dependent on the average depth required (≥80 mm minimum depth).

Accessories:

- Bauder AL150 Edge and Drainage Trim:

Perforated edge/ drainage trim, used to frame and contain the green roof build-up. AL150 is specifically designed to be used within substrate-based green roofs. It must always be used in conjunction with the pebble vegetation barrier or hard edge (such as a paver).

Usually installed directly onto waterproofing, the drainage trims can be welded down using lengths of the waterproofing membrane. The trim is used to frame the green roof build-up, and should be completed and inspected prior to living material being delivered to site. See Bauder Green Roof Installation Guide for full details.

• Material: aluminium.

• Thickness: 1.5 mm.

• Trim height/ width: 150 mm.

• Trim length: 2000 mm.

• Supply form: Joint Sections and Corner Sections are also available.

- Bauder ALU250 Inspection Chamber System:

The Bauder ALU250 Inspection Chamber is fabricated from a perforated aluminium sheet with an opening/ lockable lid, and is used for intensive and extensive soft landscaping, as well as ballasted inverted roofs. Install centrally over rainwater outlets. A simple on-site modification allows the unit to be used over outlets that are located close to wall or kerb abutments.

The Inspection Chamber is suitable for landscaping depths of less than 100 mm. Where landscaping is deeper than 100 mm, the 50 mm or 100 mm height adaptors can be added as necessary to achieve the required height, to be level with or slightly proud of the surrounding landscaping.

Surround: using 20/ 40 mm grade washed pebbles, the inspection chamber must be surrounded by a 500 mm vegetation barrier to prevent unwanted growth from obstructing the drainage system.

ALU250 Inspection Chamber:

• Material: 1.5 mm aluminium (2 mm lid).

• Size: 250 (chamber only) x 250 (chamber only) x 100 mm (l x w x h).

• Weight: 950 g.

• Colour: silver grey (RAL 9006).

ALU250 Height Adaptor 50 mm:

• Material: 1.5 mm aluminium.

• Size: 250 x 250 x 50 mm (l x w x h).

• Weight: 250 g.

• Colour: silver grey (RAL 9006).

ALU250 Height Adaptor 100 mm:

• Material: 1.5 mm aluminium.

• Size: 250 x 250 x 100 mm (l x w x h).

• Weight: 450 g.

• Colour: silver grey (RAL 9006).

- Bauder Xero Flor Organic Fertiliser:

Fertilizer should be used for ongoing maintenance purposes only, and should ideally be applied during March/ April as it helps the plants to prepare for extreme weather conditions and flowering, whilst also allowing the different species to gain sufficient nutrients without competing against each other.

Retention Angle (supplied by others):

Purpose-designed aluminium or stainless steel perimeter retention angles should be used to contain landscaping or pebble ballast when interfacing soft or hard landscaping. Used behind a waterproofed, castellated retention batten and perimeters/ top of the slope (when Bauder Trims are not sufficient in height).

• At open perimeters/ top of the slope: the retention trims are secured in place using the specified Bauder capping sheet/ waterproofing strips/ flashing pieces (1000 x 200 mm), bonded to the surface of the horizontal leg and set at intervals of 400 mm between flashing pieces. The main capping sheet/ membrane/ waterproofing must be overlapped by a minimum of 100 mm.

• Hard edge (minimum 300 mm width): the retention trims should be used in conjunction with the pebble vegetation barrier/ hard edge.

Vegetation Barrier (supplied by others):

For slopes of below 10°, a vegetation barrier must be provided to all perimeters, abutments and penetrations, including protrusions (i.e. man-safe posts, etc.). 20/ 40 mm rounded, river-washed pebbles are recommended. Stones/ aggregates with sharp edges must not be used, i.e. flint. For roof slopes of 10° and upwards, a hard edge should be selected, using paving slabs as an alternative to 20/ 40 mm round, river-washed pebbles.

In accordance with current GRO guidelines, the specified barrier widths are as follows:

• Minimum 300 mm, but increasing to 500 mm at vertical walls with opening windows or doors, or to abutments with opening rooflights.

• Every 40 m, there is a 30 mm-high barrier, constructed from non-flammable materials, or a one metre-wide strip of solid paving, gravel or pebbles.

• At all open drainage perimeters, drainage trim must be used to contain the vegetation barrier.

Jute Anti-Erosion Net (supplied by others):

• Biodegradable jute netting, installed over plug-planted/ seeded growing medium to prevent wind erosion until planting is established.

• Where the exposure of the roof is such that there is a risk of the substrate being subject to wind erosion, provision must be made to install biodegradable (jute) erosion net over the installed substrate, to prevent erosion until the plants are established. The net should be secured using biodegradable pegs.

Irrigation (supplied by others):

The need for irrigation in a biodiverse green roof system is dependent upon the client requirement for the visual appearance of the vegetation. If it is intended that the roof should have colour and interest for the longest period throughout the growing season then irrigation will significantly aid in achieving this. Should the requirement be only to deliver biodiversity then the provision of sufficient watering points at roof level to allow for only occasional watering in periods of prolonged drought can be considered sufficient. The provision of either a leaky pipe or drip line irrigation system is recommended.