How To Maintain a Green Roof

Now you have installed a green roof, the next key question is ‘How to maintain a green roof?’

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.

How To Maintain a Green Roof – EXTENSIVE M-TRAY MODULAR ROOFS

The M-Tray system is a nursery grown portable modular system that consists of an HDPE tray filled with a blend of mineral and organic substrate and pre-grown with either:

• Sedums;
• Sedum and wildflowers;
• Wildflowers only.

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
• Over seed poor growth areas if required
• 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
• Over seed poor growth areas if required
• Check irrigation system (if applicable) and drain down

For more on the M-Tray system, please click here.

How To Maintain a Green Roof – EXTENSIVE ‘ROLL OUT’ SEDUM ROOFS

Extensive roll out sedum roofs are a multi layered build up that consists of a protection fleece layer under an HDPE drainage tray (Protecto-drain) under a 300gsm re-cycled filter fleece under a loose laid blend of mineral and organic substrate under a pre-grown sedum blanket or a plug planted sedum vegetation.

Spring schedule

• Remove weeds by hand pulling
• Apply Wallbarn slow release granular fertilizer at a rate of 50gsm
• Clear debris from drainage outlets
• Generally inspect vegetation area and monitor poor growth areas
• Over seed poor growth areas if required
• 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
• Over seed poor growth areas if required
• Check irrigation system (if applicable) and drain down

How To Maintain a Green Roof – BIO-DIVERSE AND BROWN ROOFS

Bio-diverse and Brown roofs are a multi layered build up that consists of a protection fleece layer under an HDPE drainage tray (Protecto-drain) under a 300gsm re-cycled filter fleece under a loose laid blend of mineral and organic substrate. The vegetation for a Bio-diverse roof is generally plug plants and wildflower seed.
The vegetation for a brown roof is generated by natural seed dispersal from bird lime and / or wind-blown seeds – i.e. natural colonisation over a period of time

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
• Over seed poor growth areas if required
• 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
• Over seed poor growth areas if required
• Check irrigation system (if applicable) and drain down
• Cut back dead thatch and remove from the roof area

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 and seed to propagate themselves and will often recover with the onset of rain.

Further Information

If you would like any further information regarding how to maintain a green roof, please contact us on Tel. No. 208 916 2222 or via our official Facebook page and we will be happy to answer any of your questions.

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