On the occasion of his third visit to Germany, Pope Benedict XVI celebrated an open-air Mass on 25th September 2011. The Mass was held on a green space at the airfield in Freiburg. As already done for the Papal visit in Munich 2006, Werner Sobek was asked to design a weather protective Altar roof. The Altar consisted of a sacristy for the Holy Father and various other adjoining rooms for ministrants, etc. A translucent roof floating 15 m above the Altar protected the area against all weather conditions.
Most parts of the construction material could be reused or recycled after the Mass. During the design phase the focus was put on the materials which do not have to be welded or glued. Joints were only made of bolted, rotating, or clamp joints. This not only enabled a quick mounting but also served for the quick dismantling and a clear separation of the used materials. Furnishing was also carried out according to reusability. Most parts of the furniture were made for the Altar for the Papal visit in 2006. Newly designed furniture could be reused in churches.
The supporting structure of the Altar was a steel framework covered with laminar wood. The rear wall and the roof were made of a structural steelwork which was covered with fabric panels, each of them sized 3.6 x 2m and made of PVC polyester and especially in the roof area of PTFE-coated glass fibre fabric. The roof construction did not need a special structure even though it cantilevered 20m. It could be solved with a standardized support system usually carried out on temporary bridges.