Hydropack® Pre-vegetated Modular system specifications
Table of content
Part 1 – General
1.1 Description
1.2 Definition
1.3 Design Guidelines
1.4 Quality Assurance
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Part 2 – Product
2.1 General
2.2 Drainage
2.3 Hooking System
2.4 Filter Fabric
2.5 Growth Media
2.6 Vegetation
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Part 3 - Implementation
3.1 Delivery and Handling
3.2 Site Preparation
3.3 Installation
3.4 Field quality control
3.5 Maintenance
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I.
General
1.1 DESCRIPTION
Hydropack® is a prevegetated tray system that incorporates all the essential components of a traditional
green roof system. It contains an aggregate drainage layer, filter fabric and FLL compliant growth media.
Hydropack® has been used for over 1,500 projects in the last decade. Three options are available for the
vegetation: standard plant mix adapted to the climate of the region where the project is occurring; the
same standard plant mix with the addition of accent plants (Natives, Culinary or Aesthetics) and custom
planting for which possibilities are endless. Hydropack® trays lock together to provide a water and nutrient
pathway. The trays can be easily removed if needed.
1.2 DEFINITION
A.
FLL: FLL are German green roof guidelines for the planning, execution and maintenance of a green
roof. It gives general performances that a green roof should have (growth media, pH etc…).
B.
Green Roof System: All the components above the protection layer or insulation, including the
plant material.
C.
Extensive Green Roof: Low maintenance green roof consisting of a shallow depth soil between 3’’
and 6’’.
1.3 DESIGN GUIDELINES
A.
Structural loading capacity - Proper decking shall be provided by the building owner. The building
owner or their designated representative must ensure the building structure is investigated by a
registered engineer to ensure its ability to withstand the total weight of the specified roofing
system, as well as construction loads and live loads. The specifier must designate the maximum
allowable weight and location for material loading and storage on the roof.
B.
Slope - Hydropack® can be used for low slope roofs as well as very sloped roofs. For low sloped
roofs (< 5%), edges or retainers can be avoided as Hydropack® provides a sufficient separation wall
for the design of the vegetation free zones. For steep roofs, Vegetal I.D. Inc. does the engineering
study and provides two options to transfer the weight of the system onto the structure: 1) Stainless
steel cables (Ø 0.2”) attached to the green roof system to transfer the load upward to the ridge of
the roof; 2) Special edging fastened to the roof to support the trays from below.
C.
Waterproofing membrane - The module can be installed on top of any waterproofing membrane
which follows the requirements (puncture resistance, thickness,…). Please contact your
waterproofing membrane manufacturer for advice. Asphalt-based and bituminous membranes
may be subject to root growth penetration, therefore root barriers are necessary.
D.
Wind - Hydropack® mitigates wind uplift effects thanks to its integrated hooking system. Wind is
stronger at corners and along perimeters and it is advised to design vegetation free zones (12” to
24”) filled with pavers or stone ballast (10-15 lbs per sq. ft.).
E.
Vegetation Free Zones – Design space filled with pavers or stone ballast along the roof perimeter
and around the rooftop equipment. Vegetation free zone width may vary depending on the roof
environment (12” to 24”).
F.
Implementation - Hydropack® must be installed when temperature is above freezing level.
G.
Chronology - Make sure that the installation of Hydropack® is installed last on the roof and that no
work has to be done after the installation to limit traffic that could affect the plants.
H.
Protection - Prior to installing the Hydropack® modules, a slip sheet protection fabric can be
installed over the waterproofing membrane on all the areas where Hydropack® is placed.
I.
Vegetation – Sun exposure is differentiated in 3 categories: Sun; Sun/Shade and Shade. Vegetal I.D.
provides vegetation options for all 3 categories; make sure to contact them if the roof is not in full
sun exposure.
1.4 QUALITY ASSURANCE
A.
Before the installation of the modules, it shall be the owner’s responsibility to have the
waterproofing surface inspected by a technical representative of the waterproofing
installer/manufacturer, or their own roofing consultant, to determine the water tightness and the
adequacy of the waterproofing surface to accept the modules.
B.
If a plant warranty is to be issued, Vegetal I.D. Inc. has to approve the green roof project study; the
owner agrees to execute the maintenance program for 2 years with Vegetal I.D. Inc. Upon
installation, Vegetal I.D. Inc. has to inspect the green roof, and approve the installation. Contact
Vegetal I.D. Inc. for further information.
C.
A pre-installation meeting should be coordinated a minimum 2 weeks prior to the installation by
the specifier and attended by the owner, architect, contractor and other trades working on the
roofing system. The purpose of this meeting is to ensure proper protection of the waterproofing
membrane and to review the installation requirements (structural load limitations of roof deck
during installation for example).
D.
When installing the green roof, fall protection shall be in place during the whole process. Material
stock on the roof should be ballasted to prevent wind uplift damages.
II.
Product
2.1 GENERAL
Hydropack® pre-vegetated module is used for Extensive green roofs. It incorporates an aggregate
drainage layer, filter fabric and FLL compliant growth media (figure1).
Tray Dimension
2 feet x 1.3 feet (2.6 sq. ft.)
Material
Black 100% recycled HDPE
Drainage clearance above membrane 1.2 inches
Filter fabric type
Non-Woven 3 oz/sq. yd.
Water reserve sub drainage
1/5 gallons per square foot
Max. water retention capacity
3/5 gallons per square foot
Dry weight
11.5 lbs per square foot
Saturated weight
18 lbs per square foot
Max. weight per tray
45 lbs
Figure 1: Hydropack® drawing
2.2 DRAINAGE
The drainage layer has a clearance of 1.2’’ above the waterproofing membrane, which raises the growth
media above standing water if any. This design prevents the roots from rotting. The drainage layer has
water reservoirs that are filled with lightweight aggregates. 47 holes per square foot allow the water to
drain when the reservoirs are filled. Roots grow through the filter fabric to reach the water reservoir and
attach to the porous aggregates; which extend their drought tolerance. The drainage acts as both a water
reserve and a water drainage system (figure 2 and 3).
Tray material
Black 100% recycled HDPE
Clearance above membrane
1.2 inches
Water reserve sub drainage
0.16 gallons per square foot
Number of holes
47 holes per square foot
Total drainage surface
4.5 square inches per square foot
Aggregate type
Expanded Shale
Sieve No.
¾’’
Loose dry density
40.5
Figure 2: Drainage close-up
Figure 3: Drainage clearance 1.2”
2.3 HOOKING SYSTEM
Hydropack® provides a very efficient hooking system that allows water and nutrients to circulate between
the modules and mitigates wind uplift. Trays have interlocking ‘male’ and ‘female’ tabs on opposite sides
(figure 4 and 5).
Figure 4: Hooking tabs
Figure 5: Interlocking
2.4 FILTER FABRIC
The filter fabric is a non-woven fabric, UV resistant and micro perforated. It is placed in the Hydropack® to
contain the growth media. It is cut specially to fit in the tray. The filter separates the aggregate drainage
layer and the growth media. Roots can grow through the filter fabric to reach the water reservoir and
extend their drought tolerance.
Thanks to the filter fabric, the installation of Hydropack® stays clean. The filter fabric acts as a separation
wall and does not required the use of edges when installing the vegetation free zones (figure 6 and 7).
Material
Weight
Figure 6: Filter custom cut
Non-Woven
3 oz. per square yard
Figure 7: Filter fabric placed in Hydropack®
2.5 GROWTH MEDIA
Hydropack® is filled with an engineered lightweight blend customized to comply with FLL guidelines.
Different blends are available according to the job location.
Hydropack® growth media is a stable mix of lightweight aggregates and organic material. It provides
excellent aeration, water retention, erosion resistance and root penetration while remaining lightweight.
Hydropack® growth media has all the physical, chemical and biological prerequisites for the success of an
extensive green roof. It also provides excellent drainage.
Organic Matter Content
Size distribution
mass
pH 0/o
34.8 g/L
d <0.063 = 8.1
7-8.1
Soluble salts
2.56 g/L
Maximum water-holding capacity
50% – 55%
Air filled porosity at max. water-holding capacity 14%
2.6 VEGETATION
Hydropack® is delivered with a minimum of 80% vegetation cover. The plants are a mix of sedums and
other low maintenance, drought tolerant perennials that can thrive in a non-irrigated environment. 3
options are available for the vegetation depending on the location and the design intent: LEED, Culinary,
highly visible roof, accessible roof, etc…
Figure 8: Standard plant mix
Part 3 - Implementation
4.1 DELIVERY AND HANDLING
The trays are packaged on pallets: 156 square feet per pallet; 3,120 square feet per truckload.
4.2 SITE PREPARATION
A.
Sweep all debris and foreign material on the waterproofing membrane.
B.
Unroll the protection fabric directly on the waterproofing membrane and provide a minimum 2’’
overlap.
4.3 INSTALLATION
A. Hydropack® installation is very easy and fast. Generally one person can install 860 square feet in
one day.
B. Trays have interlocking ‘male’ and ‘female’ tabs on opposite sides.
C. Hold each module with the ‘female’ tabs facing the installer.
D. Place the first module on a roof corner with ‘male’ hooks facing outside.
E. Bring the next module adjacent to the module already in place and slide vertically the ‘male’ hook
into the ‘female’ hook to line them up. Do not hesitate to kick the module with the foot when there
is resistance.
F. Hydropack® can be cut with a circular saw to fit in odd dimensions. To cut the tray, lift the filter
fabric and cut the plastic tray underneath. Take off the extra growth media and plants and use the
filter fabric as a separation wall.
G. After the installation, the green roof must be watered to allow good establishment, of the roots.
4.4 FIELD QUALITY CONTROL
A.
-
Provide inspection report by checking:
That the modules are well hooked to each other
That the plants were installed the same day as their arrival on the site
That the water reservoirs are filled
4.5 MAINTENANCE
A. The maintenance is the responsibility of the owner except when a two year plant warranty is
contracted. A maintenance contract can be contracted with Vegetal I.D. Inc.
B. Short Term maintenance
- After installation, keep the traffic over the modules to a minimum. If a high traffic area develops
that was not expected, replace the modules in this area with pavers to offer a sturdy walking
surface.
- Visit the green roof one month after the installation to check if the plants are well established.
- Check drains at each visit for debris and plant material to assure that there are no obstructions to
prevent water flow to the drains.
C. Long Term maintenance
- The first two years, inspect the roof 4 times a year (April, June, August, October) to weed, check the
drains, remove the debris and replace plants if needed.
- If an irrigation system is in place, do the startup and winterization in the spring and in the fall.
- Water during drought periods: >90°F with less than 0.6” for a period of 20 days minimum. To know
if the plants need to be watered, lift the filter fabric placed in the module and check its water level.
If the water reservoir is completely dry, the green roof needs to be watered.
- Fertilization is needed one year after the installation in the spring and then every two years, with a
slow release fertilizer (18-6-12).
- From the third year after the installation, visit the green roof once in the spring to weed and clean
the drains.