Green Roof – Frequently Asked Questions

Fully established sedum plants nurtured from seed at our own UK nurseries, our M-Tray® green roof system consists of specially-designed modular trays containing superior, engineered substrate and fully established flowering sedum.

Available in easy-to-carry trays which click together to form a seamless green roof, our modular green roof system offers the easiest possible way of constructing a green roof.

We often receive questions asking for further insight and information relating to our innovative green roofing solution and the following FAQ section below has been outlined to help answer some of the more commonly received questions.

What is a green roof?

Sedum or other succulent plants have grown into low-level substrates for construction on flat roofs and podium decks.

What is a modular green roof?

An instant green roof, pre-grown at our farm in specially designed cassettes. They can be hand-carried and click together to form a seamless green roof. They are lifted into place and can be easily removed to give access to the deck.

What are the advantages of a modular green roof?

Speed of installation; accessibility; less mess and disruption; instant results; future-proofing

What is the cost of an M-Tray®?

• M-Trays®= £60m²
• Wildflower = £62m²
• Delivery = £60/pallet (32 trays)
• Geotextile fleece = £1m²

All prices are subject to alteration.

Where are the M-Trays grown?

At our farm near Basingstoke, Hampshire

How big is the tray?

500mm x 500mm x 100mm deep

How many units per m²?

4 x modules

How much do the units weigh?

100kgs/m² – we recommend that you consult an Engineer to advise on loadings (120 kg/m² saturated)

What is the vegetation?

The vegetation is a mix of 11 x Sedum species. We also have a Wildflower/Sedum mix available upon request.

Can I walk on the trays?

The modules are not designed for foot traffic but can tolerate being stepped on for maintenance purposes.

Can M-Tray® grow in partial shade?

Yes, however, like any living plant, an element of light is required.

Do I need to have any design?

No. However we can produce a layout guide along with estimates for trays, geotextile fleece and border pebbling if required.

Are there any requirements?

Yes. Fire regulations require a hard border between vegetation and the walls of buildings as well as around features such as roof lights and fall arrests (consult GRO code for more details)

Is there a full cover of vegetation?

Our M-Trays® have been grown at our farm for several months prior to delivery. They will arrive with a minimum of 90% cover.

How much is delivery?

From £60.00 per pallet (max 32 units/pallet). NB The M-Trays® need to be removed from the pallet immediately. Pebbling and geotextile fleece can be delivered separately.

Does the area have to be level?

M-Tray® can be laid on a level area and on a slope up to 15°. Ideally, we recommend not going above 10°.

Do they need maintenance?

The sedum is very hardy and will tolerate extreme conditions. Watering the sedum in extreme conditions is advisable and we can supply an irrigation kit if required.

At the end of Summer and end of Winter, we recommend taking time to remove any dead leaves and vegetation that has accumulated.

Application of a slow-release fertiliser is advisable at certain times of the year.

Do I need irrigation?

For best year-round results we do recommend installing an irrigation system although this is not absolutely necessary.

What other materials will I need to buy along with my M-Trays®?

This depends on your individual requirements.

Standard:

• Geotextile fleece to protect existing roof/membrane
• Riverstone pebbles to be used as a firebreak and to go around drains

Optional:

• M-Tray® Irrigation Kit
• Access chamber
• Aluminium edging

I have seen modular systems fail, why won’t yours?

This is our 4th generation of the module, designed and manufactured by Wallbarn here in the UK. The 100mm deep tray with its optimum drainage; our specially mixed substrate and careful choice of mature and hardy sedum species mean the M-Tray® is the best quality modular system on the market.

What other preparations should we consider prior to delivery?

The M-Tray® modules are delivered stacked onto pallets and must be unpacked within 24hrs of delivery. A crane and forklift may be needed to transfer pallets onto the roof.