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By Maeva Sabre (CSTB)

Abattoir Roof3.JPG

Pilot Id

The building was an existing industrial building. The greenhouse was built in 2016-2017, and production started in 2018.

BIGH was founded in 2015, inspired by Steven Beckers, Cradle-to-Cradle accredited architect and co-founder of Lateral Thinking Factory Consultancy that has been supporting the implementation of circular economy in the real estate sector.

After conducting different studies in 2015 for the Brussels-Capital Region on the potential of urban farming, Lateral Thinking Factory Consultancy received many requests for finding operators. They failed, so they developed their own technical support along with ECF Farm systems, a commercial business model based on aquaponics integrated to buildings where buildings support agriculture and vice versa.

In 2016, enthusiastic financial partners and technical and commercial collaborators gathered to develop the BIGH model to build the first farm of the BIGH farm network: the Ferme Abattoir.

On January 2018, following 4 months of design and permit filings supported by ORG architects + 7 months of construction work, the Ferme Abattoir was ready for phased operations.

At the end of April 2018, the farm opened officially and became accessible to the public on demand, while first products were commercialised in the Brussels-Capital region from May 2018.

Key numbers:

  • 12,000 m² rooftop

  • Greenhouse 1,400 m²

  • Aquaponics 500 m²

  • Outside garden 2,000 m²

Architect: Steven Beckers; founder: BIGH; building owners: FOODMET.

BIGH is the main contractor of the greenhouse and rents the roof that belongs to FOODMET.

Main activities: plant and fish production, visits, training sessions about vegetable (tomatoes, herbs) and fish (bar) farming.

Business – value creation

It is estimated that the electricity demand is about 260,000 kWhel/yr (50,000 kWhel/yr for LED, 210,000 kWhel/yr for the remaining appliances).
The multiple objectives of the Ferme Abattoir are to relocate production in the city, reduce energy consumption and CO² emission, reduce production costs.
The stakeholders of the project were the local authorities (i.e. the city of Brussels), the founder of BIGH (Steven Beckers), the CEO (Franck Goes).
The capital outlay was around 2.7 million euros; monthly fixed costs and monthly variable costs were not provided.


The site of the Abattoir in Anderlecht is a significant example of industrial architecture of the 19th century. The building on which the RTG was built is the most recent one on site.

This building is dedicated to the “Foodmet”, a professional marketplace for cash-and-carry of foods, etc. The roof was designed to receive a traditional garden (i.e. with natural soil) and was also solid enough to receive the resulting overload. So, why not a greenhouse structure?! The urban farming project started in 2015 with a first engineering study. To comply with the initial idea, an outdoor roof garden was designed to produce vegetables, fruit, etc.

The roof layout also includes three parts:

  • 2,000 m² for a two-floor greenhouse

  • 2,000 m² for aquaponics

  • 2,000 m² for an outdoor garden

  • the rest of the roof for pedestrian access or a technical area, and an office

  • construction lasted two years (2016 and 2017).

The host building is a slaughterhouse (abattoir) built in a heavy-weight construction type dominated by concrete elements. It was built in 2012. The rooftop is partially occupied by skylights and a few annexes.

The northern part of the roof is now occupied by PV panels operated by the host building owner. There is a permanent cooling demand for meat conservation, that makes an adequate waste heat source.

The roof would not have born the loads of the rooftop farm without reinforcements and static measures. There is no insulation in the roof, but the following layers:

  • 60 cm of reinforced concrete

  • 5 - 20 cm of lightweight concrete

  • Roofing/waterproof sealing < 1 cm.

The heavy-weight construction offers thermal mass and adequate insulation properties. The structure was reinforced to bear the loads of different zones (600, 800 or 1,200 kg/m²). The reinforcement measures also transfer the greenhouse load to the substructure. A new concrete slab was made to correct the slope of the existing roof and to protect the waterproofing membrane.

The entire perimeter of the greenhouse was covered with a Derbigum Derbipure membrane characterised by an ecological composition and a white appearance. The green roof system was installed directly on the existing membrane, with

  • a drainage layer

  • a filter layer

  • a soil layer.

There was no insulation on the existing roof, and no new insulation layer was added. Water outlets are a siphonic system. No modification was made. The transparent surfaces were made of single-glazed glass. Tempered glass was installed on the lowest part of the facade and on the greenhouse roof, and non-tempered glass on the rest of the facade. The ventilation system is on the greenhouse roof and operated with a mechanical opening system. The building is listed in the Industrial category and complies with local and national fire regulations.

The greenhouse area is about 1,300 m² and has only been used for tomatoes and herbs so far.

The greenhouse is cleared and cleaned in December. Thus, there is an 11-month growing period. The fish tanks are in separate rooms below the herb-growing area of the greenhouse. In total, 117 m³ of water are devoted to aquaculture.

Rooms for technical installations and offices are in a building next to the greenhouse and aquaculture area. They are built with recycled used containers. The roof garden is on the eastern part of the roof. It can be irrigated by aquaponics water.

The Venlo-type greenhouse is 7.6 m tall (from the floor to the roof ridge), gutter height is about 6.9 m. It is coated with single-glazed tempered glass. Vents are located on the roof. Energy screens are installed at gutter height, but there is no shading device. The main axis is oriented north-east to south-west.

The growing systems are fixed to the roof, so most of the loads are distributed to the outdoor elements of the greenhouse. Additional steel pillars inside the greenhouse secure the distribution of the load to the perimeter, which stands on reinforced structures of the host building rooftop.

The cultivation system is based on baskets suspended on a line. This way, the whole growing media and vegetable loads are mounted on the greenhouse structure. Only the heating system is fixed to the floor. The aquaponics system is placed directly on the floor.

Technical rooms are located along a corridor that separates the greenhouse from the fish production room. The outer wall is made of concrete; the partition wall is made of wood. Office containers are also directly on the bearing beams of the host building structure.

Three types of water are used to compensate for losses: rainwater, tap water and well water. Aquaponics is supplied with well water. There are 3 tanks of 35 cubic metres each, for a total of 105 cubic metres (temperature 24°C). Water must be heated from 10 - 12°C to 24°C. Losses are estimated to be approximately 5% of the total volume per day (6 to 8 m³/d). The water network is made of PE or PVC pipes, depending on the shape and installation.

Energy management

The greenhouse is a Venlo type structure with higher-than-usual structures (7.6 m). It was built with single-glazed windows, with the row closest to the ground made of tempered glass. For information, FOODMET had installed a photovoltaic system on another roof of the building.

All possibilities of reducing energy consumption were investigated based on recent standards or best practices, and no special energy advice was provided during the planning phase.

The greenhouse is heated, but not cooled, and there is little mechanical ventilation.

The host building has a steady cooling demand creating waste heat which is utilised to heat the greenhouse with a 140-kW heat pump. This constant flow at 15 °C on the primary side of the heat pump leads to a COP of about 5-6. The heat pump operates up to a water heat temperature of 60 °C.

In case of peak loads, the greenhouse is supplied by two gas boilers with a capacity of 100 kW each. In case of redundancy, the heating loop of the host building can be tapped. It is planned in such a way that the growing phase is interrupted each December for the interior to be cleaned and the growing systems to be adjusted. The total heating load was estimated to be about 380 kW (To= -5 °C, Ti = 20°C; 15 °C, ∆Twater= 12 K).

It is estimated that the annual heating demand is about 600,000 to 700,000 kWh (tomatoes 250,000 kWh/yr, herbs 150,000 kWh/yr., fish 270,000 kWh/yr). The estimation is based on a specific heating demand of 300 kWh/(m²yr) for the tomato area and 260 kWh/(m²yr) for the herb area.

There are 3 storage fridges cooled to 7-11 °C (plants) and 0-3 °C (fish); they are not used for waste heat recovery.

In terms of electricity, the farm needs a connection power of 290 kW (including 60 kW for LEDs) in total. Consumers are the heat pump, fans, pumps, the chiller, lighting, growing lights (LEDs).

The greenhouse itself is equipped with few energy screens at its top and some of the waste source of CO² is used, but the effect is not measured.

Here are examples of measures that could be retrofitted: the growing concept could be adjusted to operate at lower temperatures in winter and transition periods. Thus, leafy greens could be an option. This must be tuned within the aquaponics system. A shading system could be installed to reduce solar influx in summer. Measures that cannot be retrofitted could be using F-Clean film instead of glazing to reduce the weight load of the greenhouse and could also lead to a different and cheaper bearing structure. In addition, double-layer ETFE constructions have much better insulation properties. Double glazing could be used instead of single glazing. In this climate zone, losses in solar heat gains should be more than compensated for by the reduction of heat transmission


Aquaponics greenhouse farms are located on unexploited commercial rooftops or land in urban or suburban environments. The farms are closely linked to the operation fluxes of the buildings.
High-tech production is integrated and fully transparent. A circular economy policy and zero waste of fresh natural vegetables, fruit and fish benefit from the fatal energy and CO² from the building’s systems.
Fish and vegetable production goes on throughout the year. Two months are required for the maintenance of the tomato production area (November and December).
After the construction works, a certain period of time is required before production to adjust the aquaponic systems: regulate water quality, growing media composition, etc. to adapt to the fish and tomatoes that BIGH want to produce.
Production started in March 2018. Crops are tomatoes, herbs (basil, coriander, parsley, etc.). The expected greenhouse life cycle is 10 to 15 years.
Five people are employed daily to manage the activities of the Ferme Abattoir (visits, crops, packaging, etc.).
People involved in the project come from all over Europe (including France and Belgium). They get skills in biology, aquaculture, agronomy, horticulture, marketing, architecture, etc.
The Ferme Abattoir is also an attractive place for trainees.
Building Integrated Green Houses Holding SCA (BIGH holding SCA), the developer and operator of aquaponics urban farms, is raising funds to close a financing round aimed at developing its network of urban aquaponics greenhouse farms in Belgium and abroad.

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