Ground Area Ratio for warehouses

The Ground Area Ratio: Definition and Building Law Basis

The Ground Area Ratio (GAR), or the Site Coverage Ratio (SCR) is the measure of the structural use of a property in accordance with the Building Use Ordinance (BauNVO). It specifies how many square metres of floor space per square metre of land area may be permissibly built over.

GAR = Floor area of the building / Area of the property

In practice, the Ground Area Ratio is the indicator for the "density" of the development. A value of 0.8, for example, means that 80% of the property may be built over.

While this is often a question of aesthetics and green spaces in residential construction, the Ground Area Ratio decides on "to be or not to be" in the logistics and industrial real estate sector. Since logistics space is extremely space-intensive (both due to the halls and the outdoor areas), the Ground Area Ratio is probably the most important key figure in project development.

Ground Area Ratio in logistics: Why it works differently here

Unlike office or residential properties, which can grow upwards (regulated by the number of floor areas, Ground Area Ratio), logistics properties are usually single-storey low-rise buildings ("big box"). Value creation takes place in the area.

For developers of logistics parks and contract logistics companies, a plot of land is only valuable if the relationship between warehouse space (revenue generation) and land price is right.

Typical challenges in logistics:

• Large "footprints": A 10,000 m² hall requires an enormous amount of floor space.
• Massive outdoor areas: A logistics center does not function without loading yards, truck waiting areas, sprinkler tanks and car parking spaces for shift personnel.

For this reason, logistics companies always strive to make maximum use of the Ground Area Ratio. A property with a permissible Site Coverage Ratio (SCR/GAR) of 0.4 (typical for general residential areas) is effectively worthless for logistics purposes. It only becomes interesting from a Site Coverage Ratio of 0.6, ideally 0.8 in commercial areas or industrial areas.

The decisive difference: main plants vs. ancillary plants (GAR I and II)

For specialist planners and investors, the trick lies in the detail of § 19 BauNVO. In practice, a distinction is often made between the "main GAR" and the "total sealing".

1. The main plant (GAR I)

This concerns the actual building (the warehouse, the distribution center).

• Example: On a 20,000 m² plot with GAR 0.8, the hall should theoretically be 16,000 m² in size.

2. The ancillary facilities (GAR II / sealing)

This is where it becomes critical for logistics. According to § 19 para. 4 BauNVO, the area that can be built on also includes:

• Garages and parking spaces (truck docks, employee parking).
• Driveways and manoeuvring areas (the "Truck Court").
• Ancillary systems such as sprinkler control centres, gatehouses or underground tank systems.

The problem with the capping limit: The BauNVO allows the fixed GAR to be exceeded by up to 50% by these ancillary facilities, but only up to an absolute upper limit (capping limit) of 0.8.

In practice, this means that if a GAR of 0.8 is set in the development plan, it may not be increased to 1.2 (0.8 + 50%) by ancillary facilities. 0.8 is usually the limit (unless there is a specific exemption). Since logistics properties require huge concrete outdoor areas for 40-ton trucks, the loading yard often "eats" up valuable points of the GAR, which are then missing for the actual hall.

Practical check: Typical key figures and area ratios

In order to check the profitability of a logistics settlement, project developers work with rules of thumb.

Why only about 50% hall space at GAR 0.8? Although 80% sealing is permitted, about 30-35% of the land area is used for the necessary outdoor facilities (truck bypass, docks, car parking spaces, distance areas, green strips). The hall itself can rarely take the full mathematical 80% without paralyzing operational logistics.

FAQ: Frequently asked questions about GAR in logistics practice

Here we answer specific questions that arise in the project development of warehouses.

Do canopies count as GAR?

Yes and no. A classic canopy over the loading gates (weather protection) is usually part of the floor area if it has a constructive space-forming effect or has supports. However, there are nuances in many state building codes and development plans. The decisive factor is the "covered area".

What happens if I exceed the GAR (possibility of exceedance)?

A slight exceedance is possible according to § 19 para. 4 sentence 2 BauNVO if the soil is not significantly impaired (e.g. by using lawn grid stones on car parking spaces or permeable pavement). In logistics, however, this is often technically difficult to implement for truck areas due to the high point loads (concrete/asphalt is mandatory).

Do outdoor shelving systems count as GAR?

Yes. A permanently installed outdoor warehouse or pallet rack is considered a structural facility and puts a strain on the GAR. This is often overlooked by companies in building materials logistics.

Does GAR play a role in existing properties (brownfield)?

Absolutely. Many older logistics properties have a very high utilisation, which would no longer be eligible for approval under current building law (grandfathering). In the event of an extension or a new demolition building, the currently valid (often stricter) GAR can lead to a loss of usable hall space.

Economic impact of GAR on contract logistics

For the contract logistics company, the GAR is a direct cost factor.

1. Rental price calculation: The investor buys the property per square metre (€/m²). If he can build less hall space due to a low GAR (e.g. 0.6 instead of 0.8), he must allocate the entire land investment to fewer rentable square metres. The rent per m² of storage space is increasing.
2. Third-party usability: A property that the GAR maxes out often has too little outdoor space. This may be okay for an e-commerce retailer with little outgoing goods, but for a freight forwarder (cross-docking) with a high volume of trucks, the site is then "too narrow". A balanced use of the GAR ensures the resale value.

The "full sealing" – exceptions in the industrial area

In purely industrial areas (§ 9 BauNVO), there is the possibility of deviating from the strict limitation of sealing under certain conditions, provided that ecological compensatory measures (ecopoints, green roofs, retention areas) are created elsewhere or at the property.

Modern logistics properties often try to defuse this conflict by green roofs or PV systems in order to collect arguments from the approval authorities for maximum utilisation of the GAR (up to the capping limit of 0.8 or, in individual cases, beyond that by exemption).

Conclusion: The GAR as the bottleneck of logistics planning

The floor area ratio is the first value that a logistics project developer checks in the development plan. It determines the volume of business cases. While in residential construction the height is often limited, in logistics soil sealing is the limiting factor.

Anyone planning or renting warehouses must understand that the GAR not only dictates the size of the hall, but also the ratio of "storage capacity" to "traffic area". A healthy ratio on a property with GAR 0.8 is usually about 50-55% hall area and 25-30% sealed outdoor area. Anything beyond this often leads to operational bottlenecks on the farm or to licensing hurdles.