With its decision last December, the Federal Supreme Court prevented the construction of a housing estate on the noisy Bederstrasse in Zurich. Two experts from the cantonal building department explain the consequences of this judgment.
Building on noisy streets remains extremely challenging.
When the noise protection ordinance came into force 35 years ago, the legislator assumed that the noise problem would be solved within 15 years. Sure, a lot has happened. The rolling stock of the railways is z. B. become considerably quieter. Different with the still dominant street noise. More traffic, heavier and larger vehicles and wide tires have more than offset all efforts to build quieter vehicles.
Noise pollution can be reduced with measures at the source – with low-noise coverings and tires or the politically controversial 30 km/h on main roads. But the fact remains: the noise pollution is so high on many road sections that even a combination of all measures is not enough to comply with the limit values. Measures on the buildings will therefore also be necessary in the future.
Live closer together, but not louder
How and where should we live in the future? Spatial planning does not want our settlements to get out of hand and calls for inward development. But building more densely also means building in the midst of noise, and this will tend to increase as a result. This density will only be accepted by the population if it doesn’t get louder – according to a study by the Office for Spatial Development in the Canton of Zurich. Public spaces and local recreation opportunities are becoming more important. Less noise is also required here, not only in our apartments.
Years ago, the noise protection department of the Canton of Zurich developed a practice with the aim of reconciling the legitimate requirements of noise protection as health protection with the equally legitimate specifications of settlement densification and the dictates of urban development. With the so-called ventilation window practice, construction projects were approved if the noise limit values were complied with at the window that was least exposed.
The limit values did not have to be observed for the other windows in the same room (so-called second windows). These were therefore also permitted on noisy street facades. The approval practice was based on the assumption that the residential hygiene and the urban development conditions would be improved by the second window without any adverse effects.
Ventilation window practice undermined
The residents could close the second window if they felt disturbed by the noise and only open the window that was shielded from the noise to ventilate the room. Exceptionally, noisy rooms facing the street were even possible if it was unavoidable and this was compensated for by a really quiet room away from the noise and a quiet outdoor space. In this way, the principle was realized that apartments on noisy streets must also have a quiet side.
This ventilation window practice was called into question by a federal court decision of July 2016, which referred to the construction of a housing estate in Niederlenz (AG). The Federal Supreme Court took the position that every window is considered a reception point and must therefore comply with the immission limit values. However, ventilation windows are a good measure when settlement development and urban planning require it.
From today’s perspective, the statement made at the time that the second window facing the street must not be exposed to significantly more than the immission limit value (IGW) is fatal. On the one hand, the decision gave more weight to noise protection, but on the other hand, it made it clear that an exceptional permit is required for every window that exceeds the limit value. Housing construction is simply no longer possible along all the traffic facilities in the densely populated settlement area without exceptions.
Irrespective appeals from the neighbors
The noise protection ordinance explicitly provides for such exceptions, but they require an overriding interest. In the building permit process, such deviations from the standard construction method are always tricky and open the door to complaints from the neighbors. Frequently, these appeals are not really about noise protection, but about personal, actually irrelevant concerns such as preventing new buildings or the view – and maybe sometimes even just about money.
Such appeals have previously set a precedent in the canton of Zurich. The courts judge strictly formally and stop construction projects if the optimization is not presented in detail from the beginning or if the interests were not weighed up sufficiently. In addition, exceptions must represent the last resort, i.e. ultima ratio.
Last year, the Federal Supreme Court revoked the building permits for two construction projects in the canton of Zurich for formal reasons due to insufficient documentation. Accordingly, it no longer examined the projects materially. In a material examination, both projects would have had a good or at least intact chance of being approved.
The central question is the level exceeding at the second window, which is directed towards the noise source. Since the courts do not differentiate between the ventilation window and the second window due to the decisions of the Federal Supreme Court, absurd situations arise. This second window could namely be left out if the prescribed window area is reached with the ventilation window. Then there are no exceptions. The price is forbidding facades, inappropriate lighting, no ventilation or no connection to the public street space.
The situation is difficult for builders who want to build in noisy locations. Three scenarios are open to them – all of which can have negative consequences:
1. Good buildings, but risk of recourse: Good projects continue to be developed, but they require exceptions. These are justified in detail and convincingly (depiction of the optimization of measures and weighing of interests). Wherever possible, rooms whose level is also exceeded at the ventilation window are avoided.
In the case of very high transgressions on second windows, these are permanently glazed – although not necessary from the point of view of noise protection. Although this does not exempt from exceptions, it can be used as a noise protection measure. What remains is the risk of recourse and the associated delay that may be considerable. Conclusion: These construction projects are optimized in terms of noise protection and settlement compatibility. Only the scope for new forms of living is somewhat limited.
2. Blind facades, urban deterioration: More and more projects are being developed that do not require exceptions. This requires that the immission limit values are complied with for every window. In this case, the result is poor architectural floor plans with long internal circulations, blind facades with no living room windows facing the street and small, closed kitchens. According to the law, these mini-kitchens with an area of less than 10 square meters are not sensitive to noise, but they contradict the criteria of modern residential construction.
Conclusion here: In contrast to the intention of the Federal Supreme Court, there is less optimization, since exceptions are no longer necessary. It is to be hoped that the deterioration in urban planning will be prevented by the town planning commissions of the communities and that the builders will risk the refusal of the building permit. This won’t be easy. Why should the authority demand good projects that are only possible with exceptions, when it can be done without?
3. Construction waiver, compaction comes to a standstill: If the last resort should actually mean that, for example, only a minority of projects are allowed to claim exceptions at all, the court decisions lead to disaster. Builders refrain from building new buildings in noisy areas. The densification in urban areas desired by spatial planning is faltering. Due to the high demand for residential buildings, construction activity is increasingly shifting to the periphery of the agglomerations, where building land reserves are still available.
As a result, car traffic increases due to poorer public transport connections. The overall noise pollution increases and the noise is distributed over the whole agglomeration. In the centers, old buildings with catastrophic noise exposure are no longer being replaced, and the residents continue to be exposed to significantly higher noise exposure than in a new replacement building due to the protection of existing buildings.
Settlement quality is not improved
With its decisions, the Federal Supreme Court probably wanted to give noise protection more weight, increase the pressure on measures at the source and thus also improve the quality of the settlement. Inadvertently, it has achieved the opposite. From an economic point of view, construction projects must go through the approval process as quickly and safely as possible, which is only possible without exceptions.
The good quality of living, the appealing urban development with connections between living and public space and the fight against noise at the source, since no more windows facing the street have to be noise-remediated, fall by the wayside. What kind of noise protection do we want in the future? The legislature should answer this question.
Gerhard Schmid is the head of legal services in the cantonal civil engineering office. Thomas Gastberger is the head of planning and building in noise at the canton’s noise protection department.