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Green roofs

An image of a green roof

What makes the M-Tray® green roof unique?

  • Mature, established vegetation
  • Click-together trays create seamless connection
  • Easy to transport and install
  • Specially-mixed substrate for longevity of plant life
  • 100mm deep cavities for healthy roots
  • Optimum drainage means stronger plants
  • No sharp edges or mess meaning minimum disruption to plants, deck structure and inhabitants!

Video: 2 min overview on the M-Tray®

An image of a fully installed green roof

Instant green roofs

  • M-Trays® are designed to click together forming a single verdant surface
  • Once trays are connected they start to blend straight away, forming a seamless layer of vegetation
  • Modular M-Trays® can be easily lifted out giving access to the deck without disruption to the rest of the roof

Video: breathtaking Dorset development

Sedum green roofs packed on pallets for transport

Quick & easy to install

  • Hard-to-access areas such as single storey extensions, working hotels and other commercial spaces can make installing roll-out very challenging
  • M-Trays® can be handballed into even the most awkward areas discreetly and with minimum mess
  • Each M-Tray® module is 500 x 500mm and can be carried by one operative and therefore installed much faster than traditional roll-out
  • Our modules are conveniently packaged, palletised and delivered to site
Unique Design

Unique Design


  • Module measures 500 x 500 x 100mm
  • 4 x units make up exactly 1sq metre making  estimating far easier
  • Carefully spaced drainage holes ensure modules retain water for longer, allowing plants to absorb more rainfall, increasing attenuation and delaying discharge into outlets
  • Design ensures even greater water retention at edges of module, preventing sedum from dying back at the edges.
  • Stronger plant growth at the edges creates a more seamless layer of vegetation when the modules are connected
  • Four gently ridged hand grips are positioned to enable installers to carry each module easier


Smooth edges & connecting bracket

  • The connecting brackets are designed to give a tight connection, with the minimum gap between each module
  • The joint is only 6mm so the plants will grow over it quickly, making it disappear in ultra-quick time
  • The corners of the modules are rounded and smooth, so no sharp edges (which might puncture the membrane beneath) are present – this also makes handling the trays easier and the edges can be mounted onto Wallbarn pedestals if additional height is required


Trims & Edging

100mm aluminium edge trims and connectors fit neatly onto the sides of the modules. Fixings are designed to slot together neatly although they are not always necessary.



Access to your green roof is futureproofed.

If there are problems with the deck beneath or inspection is required, one M-Tray® or section can easily be lifted out without disruption to the whole roof, unlike roll-out which often involves the removal of tonnes of soil and vegetation, which then would need to be replaced at an additional cost to the client.



As well as the sedum trays, Wallbarn plants up a wildflower mix into the M-Tray®.

A varied mix of at least six different native species has been selected. All these flowers and herbs are low growing, hardy species, chosen to be pollinators for butterflies and bees.

Bespoke options are available.



What is a green roof?

Sedum or other succulent plants 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 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 have 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.


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


  • 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.


Export & Licensing opportunities

As well as supplying live products for installation on UK green roofs and landscaping spaces, Wallbarn is committed to M-Tray® as an export product.

We can supply the modules as empty trays for local landscapers worldwide to plant up and propagate according to the local climactic conditions and their own markets.

Licensing opportunities are available for both the M-Tray® brand and the mould, which can be granted to specific partner companies across the globe.

M-Tray® has been designed and developed by Wallbarn in the UK and is the subject of Community Registered Design (No. 002953943-0001) and US Design (Application No. 29/553,129). Further worldwide design registrations are currently being carried out.

Our aim is to get more green spaces into urban centres worldwide. With M-Tray® this is a possible and economically viable prospect. Join us in our vision.



Below you will find the basic steps for successfully installing a modular green roof.

Alternatively watch one of our videos

M-Tray® modules are transported to site on strapped pallets for easy, clean delivery. They can then be craned safely onto the roof if necessary.

Unpacking the pallets is a simple process. None of the contents will spill out and each module can be carried by one person.

A separation and filtration geotexile layer should be firstly installed. This protects the waterproofing and prevents abrasive damage. Wallbarn usually supplies a 300gsm recycled fleece for this purpose

Start from the middle of the green roof and work outwards towards the edges. Place a module down and then click the next into place. There are two connection points on two sides of each module. Once connected up on all four sides, the module will be secured on all four sides.

An aluminium edge trim can be added to any exposed edges or where the stones need to held away from objects such as drainage outlets.

The modular sections mean detailing around objects is a simple process and clean lines are created. Hard landscaping sections such as paving and decking, mounted onto Wallbarn pedestals, can be added to the area to allow for regular access. As everything is suspended on top of the deck, drainage is uninterrupted.

An installation guide for M-Tray® is here.

More help to prepare the roof, how to connect the trays and how to install the edging.

Have you considered an irrigation system?

ProductM-Tray® Modular Green Roof Container
Suitable ForExtensive Green Roof Plants With Lightweight, Free-Draining Substrate
Type Of ConstructionPermanent
Width / Breadth500mm X 500mm
Shape Of Walls / SidesTapered / Angled
Units Per M24
MaterialRecycled Polypropylene
Thickness Of Material3mm
Internal Ridge Height / Reservoir Height20mm
Number Of Internal Drainage Reservoirs25
Drainage Holes Per Unit8
Distance Between Trays At Base20mm
Distance Between Trays At 50mm From Base10mm
Dry Weight (Empty)1.1Kg
Weight Planted & Saturated *32Kg
Connectors Per Unit4
Number Of Handles On Underside4
Detail Of Corners / EdgesSmooth / Reinforced
EU Design TrademarkNO 002953943-0001
US Design TrademarkNO 29/553,129
* Filled & fully planted field capacity of Wallbarn substrate & mature sedum plants during / after abnormal rainfall conditions.

CAD Drawings

  • M-TRAY 2016 Module
  • M-TRAY Derived Assembly
  • M-Tray System Build-Up
  • M-Tray® 2016 module 3D

NBS Plus

BIM Library

M-Tray® 2016 module 3D