Hydrocell applied Roofgarden in Norway Vertical farming
Case Study

Green roofs - Hydrocell®.

We give you the materials to create an environmentally friendly way to insulate your building. For instance roofgardens and vertical gardens. Also helping the world become a greener place.

Hydrocell® Green Roofs

Hydrocell® - Green roofs & light weight roof gardens

Hydrocell flakes are a unique soil improver with remarkable water holding properties. It looks like polystyrene flakes, but mixed into your soil or potting mix, Hydrocell® holds up to 70% of its volume in water. Hydrocell® is suitable for all gardening applications including tree planting, garden beds, lawns, potted plants and roof gardens.

The Hydrocell green roof , roof garden system is ideal as subsoil for moss-sedum, herbs and grass vegetation mats. These mats are a good alternative for e.g. gravel roofs. The great advantage of moss-sedum mats is the immediate visibility of a colourful green carpet after laying.

Hydrocell and Fytomix applied on a roofgarden

Environmental aspects

Everything we install in our environment has to be checked in accordance with its biodegradability. Hydrocell®  foam is biodegradable because it degrades by means of hydrolysis within a period of 20 years to nitrogen which in turn functions as a need for plants. 

Root supply

The water absorbed will be supplied gradually and completely to the plants which grow with their roots in the hard foam. This in contrast with poly-acrylamides, expanded clay or lava which are buffering quite a lot of water, but supply only a small part of it to the roots.

Why should you get a green roof with Hydrocell®?

Hydrocell is:


A safe and suitable system for architects and developers

Self water regulating throughout the year

No further maintenance of the system after installation and therefore profitable

Hydrocell flakes applied in a layer of 10 cm, has a water absorption capacity of max. 70 litre/m2 (70 vol%)




Empty space percentage amounts to 70% as a result of the open cell structure

Very durable and solvent-proof even under extreme climate conditions

Roofgarden Brewery Wharf - Leeds

Brewery Wharf, Leeds

Located on the River Aire in central Leeds, this 326 apartment residential scheme by Robinson Design Group incorporates a 2,500 m2 Icopal green roof. The roof system to the front of the development is situated at ground level with the car park underneath. The garden forms a communal leisure space for residents.

Substrate system:

The roof garden itself comprises a high performance rootbar capsheet with a Fytonop® 20 drainage board and a filter fleece. This is topped with a lightweight soil mix. To enumerate: 30% sandy loam, 30% peat free compost and 40% Hydrocell flakes.

St John’s School, Marlborough Intended to unify a split school onto a single retained site. Format Milton Architects’ low impact design is intended to reduce energy consumption by 50% from that of the two current sites. The school is conceived as an extension of the hill top. The grass roof follows the curvature of the site. Significantly giving the impression that the landscape has been gently raised to accommodate the school below. In addition the design also uses recycled materials, high levels of insulation and photovoltaic roof glazing.

What are the

3 types of roofgardens

Intensive green roofs

The intensive profile is deeper, between 200-1200 mm. Therefore allowing a large diversity of plants and trees to grow. Obviously these gardens are generally used as recreational spaces. For this reason we use the Hydrocell layer application.

Semi-extensive green roofs

The medium profile. In fact 100-200mm. This allows a great diversity of plants. But you can’t grow (big) trees here. In order to do this we use Hydrocell of Fytomix.

Extensive green roofs

Comprises of a shallow profile of between 500-1000 mm. We advise this for low maintenance gardens. With this in mind, low growing plants like mosses, sedums and grasses are what you’ll find on these gardens. In addition weight savings is key. With our substrates you can make roofgardens, where this otherwise might not be advisable.

To summarize, we use flakes in substrates, to create more intense gardens. At the same time reducing overall weight of the soils.

Examples of green roof projects with Hydrocell®

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