Forschungs-Blog

Unser Weg zu einem klimaneutralen Gebäude

Keeping grip on the process as a team

Or how to not negotiate away the wood

In Brötzingen, municipality of Pforzheim, we visited a landmark in the making: Carl. Fourteen stories high, of which 13 are in a hybrid wood construction. The website of the project is in German only, but the one of the contractor has key data in English as well.

Exkursion Carl Baustelle
Exkursion Carl Baustelle

The research team on site. Photo: Marieke (Vis-à-Wien)

We enjoyed visiting the building site and having a nice view over the area. It was nice to see that even today, places still do have different building traditions. The Austrians were quite surprised to see bricks being applied in the basement floor of the project. The Germans wondered in turn that their Viennese colleagues would always use a concrete slab as the floor for a parking garage. If there is no water pressure that gives the risk of water coming in from below, they prefer to use bricks and save on concrete.

The decision-making was very interesting for us. How do these things work? Well that was quite sobering: not everything is being constructed exactly as it was designed. Besides the tower, there are two long blocks of four and six stories that were initially planned in wood as well. For one of them this shifted to concrete during the negotiations, after a discussion of just fifteen minutes. The logistics of the fire safety with two wooden blocks close together was an element in this decision, as well as the price.

That was rather shocking. Imagine the inspiring plans for our wood construction being shifted to concrete in less than an hour, simply to solve some budgetary issue!

Martin Magometschnigg of developer Schwarzatal was part of the excursion as well. He could reassure me:

Martin Magometschnigg auf der Baustelle von Carl

Martin Magometschnigg (Schwarzatal) on the site of Carl. Photo: Marieke (Vis-à-Wien)

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In our project such a far reaching decision could never be taken in just 15 minutes. All our decisions are embedded in a carefully designed process. As a group you are involved in that process. There is a special Allocation Team consisting of members of Vis-à-Wien that is involved in this phase when price negotiations take place. There are meetings between us as the developer and the architects as well as with this Allocation Team. This assures that all decisions are well balanced.

Some of us were not so impressed by buildings like Carl. Wood on the façade gives a nice look but it is really just that: a façade. The construction still had a lot of reinforced concrete. In the discussion afterwards the group concluded that a wooden construction where it is not even visible because the façade is of another material, is preferable above such a ‘wooden look’. In our research we will compare such alternatives in order to quantify this feeling about what has more impact on climate performance.

Excursion key data:

Date:  05.10.2022

Location:
Carl, Brötzingen Mitte, Pforzheim, Germany; Peter W. Schmidt Architekten

Guides/Experts:
Stefan Mederle, Zueblin, GU-Vertretung;
Sandra Pauser, PWS, Projektleiterin Carl

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