Green roofs are living structures and as such need attention throughout their lifespan. Some vegetation types such a sedum are planted as they require less maintenance than grass roofs for example. However, regular attention to soil moisture and feed levels as well as the removal of weeds is essential to maintain optimum performance.

Extensive green roofs including M-Tray® modular roofs

Spring schedule

• Remove weeds by hand pulling only
• Apply Wallbarn slow release granular fertiliser at a rate of 50gsm
• Clear debris from drainage outlets
• Generally inspect vegetation area and monitor poor growth areas
• Insert cuttings from good growth areas into bad growth areas
• Check irrigation system (if applicable) and replace timer batteries

Autumn schedule

• Remove weeds by hand pulling only
• Clear debris from drainage outlets
• Generally inspect vegetation area and monitor poor growth areas
• Cut back dead stalks or dying vegetation
• Insert cuttings from good growth areas into bad growth areas
• Check irrigation system (if applicable) and drain down

General points

Sedum

Sedum is a unique plant in that its metabolism is reversed from most other plants. Sedum closes its stamen during the day which contributes to it being more efficient at conserving water. Sedum leaves will change their colour at times throughout the year and will often take on a russet colour during, drought, strong wind and frost. This is normal and they will revert to their normal green hue over time. Should the stems and leaves start to ‘shrivel’ back then this is a sign of a problem and in the main lack of water. Irrigation must be applied to reverse this and the levels of water checked for several weeks until the sedum has recovered.

Wildflowers

Wildflowers are weeds and weeds are wildflowers and so care must be taken during maintenance NOT to pull out healthy and desired plants. Wildflowers by their nature thrive on poor soils where there is little competition however they are more vulnerable to drought. Drying of stems and leaves will be seen through hot dry periods and although irrigation can be applied it is not a requisite as the ‘stressed’ plants will flower

Delivery
The M-Trays® are delivered on pallets to the kerbside. It is the buyer’s responsibility to move the pallets from the kerb to the roof/podium.

Unpack immediately
Unpack the M-Trays® from the pallets immediately upon delivery to prevent the sedum plants being crushed. If left stacked for more than 24hrs sedum will start to decompose and die.

Handballing trays
The trays can be easily transported by hand to where they are being laid.

Prepare your roof
Ensure the roof membrane is properly protected and free from dirt and debris. Roll out the supplied geotextile fabric, ensuring an overlap of 20cm. This will act as a protective layer and a filter for drainage.

Install metal edging
Once the geotextile is laid, install your aluminium edging (optional). This is placed around the perimeter and loose laid into position. Do not mechanically fix the edging into the waterproofing membrane.

Start placing the trays
The trays are laid over the geotextile fabric and clicked together. They fit over the base of the edging bar.

Tray orientation
Each module has 2 x clips on the North side and the East side; and 2 x recesses on the South side and the West side.

Lay irrigation piping
If an irrigation system has been purchased, install as you lay the modules (see irrigation guide) by laying the pipes in between each tray at the base.

Aligning your trays
Repeat the process across the roof taking care to ensure the rows of M-Tray® are properly aligned.

Clipping trays together
Click each module into position ensuring clips are connected over the recess points.

Adapt the trays
For curves, details and end-of-runs, the M-Tray® modules can be easily adapted using a wood saw. Take care not to dislodge the substrate or vegetation too much.

Press open sides together
The open side(s) must always be pressed up to the side of the neighbouring M-Tray® in order to retain the substrate / growing medium.

Create a hard border
Fire Regulations state that M-Trays® must not be installed right up to buildings, walls, roof lights, hatches, mansafes, vents, drainage outlets, or other protruding objects.

Riverstone pebbles
A riverstone pebble border of at least 200mm width should be installed at these points (See GRO Code for guidance on building green roofs).

Irrigate once installed
After installing the modules, it is essential that you water them thoroughly until fully saturated.

If an irrigation system has not been installed, water by hand.

Fertilize the vegetation
It is recommended that you scatter slow-release fertilizer by hand across the whole roof at the rate of 25 grammes per m2 (a handful).

Even hardy sedum and wildflower green roofs will require irrigation during periods of dry weather (3 weeks without rain during spring, summer) or very hot weather. If the roof starts to turn red it is in distress and requires watering.

Simple, manual irrigation

For smaller (typically less than 50m2) easy to access green roofs users should safely gain access to the roof and irrigate manually, e.g. a hosepipe, watering can.

Manual irrigation system

Tap fitting irrigation kit for extensive green roofs with standard fittings and 180° spray nozzles and 16mm pipe. For attaching to garden tap fitting for ad hoc manual irrigation (supplied without water filter).

Assembly instructions

Please see the video to the right

Unpacking

Lay out all of the components and familiarize yourself with all of the parts.

Supply

To reach a ground level water supply from a rooftop we recommend you run your 16mm piping down some existing vertical guttering. Check your water pressure: it needs to be at least 1bar.

Laying your pipe

Lay piping at the same time as you are laying your trays. Line up your 16mm piping flat on the ground, laying it in between the trays.

Positioning your risers

180° risers will produce a 3m spray arc on a standard 2 bar pressure tap. Position the risers, so that the jets overlap ensuring all of the green roof gets adequate water.

Pierce piping

Use the yellow barbed key to puncture your 16mm pipe ensuring your holes are no more than 3m apart so their sprays overlap.

Attach jet to riser

Insert the vertical rigid riser into the hole you have created in the pipe, then screw clockwise. Point the jets away from walls and upstand.

Attach riser

Select the appropriate Vari-jet nozzle for your tray layout (360° or 180° if up against a wall) and attach to the top of your riser.

A 90° jet is also available.

Pipe joiners

3 x types of joiner are supplied to allow you to extend/change the direction of irrigation:

• Straight
• Elbow (right angle)
• T-junction
• Plumbing

Connect to your water source: insert your 16mm pipe directly into your tap connection (filter optional).

Filter system (optional)

We recommend a filter system, to be fitted between the tap and your piping, in order to prevent the jets clogging with grit or hard water.

Terminate your system

Insert the straight-ended stopper into the piping to terminate the system.

Automated holistic irrigation system

Bespoke, sophisticated irrigation systems designed by horticultural and irrigation experts. Roof scale plans would need to be reviewed to produce specific, tailored irrigation system suited to the individual aspects and constraints of the roof. Aspects such as size, height, orientation and exposure, water pressure etc. are considered when designing the system.

Web based control systems which monitor substrate moisture levels, leak detection and irrigation schedule are available. A large range of different designs at different price levels are available.

These systems are typically for largescale green roofs.