Following promotion straight back to the Bundesliga in the 2017/2018 season, VfB Stuttgart started work on the extensive modernisation of its training ground in Mercedesstrasse in Bad Cannstatt. The club kicked off the season by replacing the outdated synthetic playing field with a modern football system from Polytan – the old one dated back to 1999 and had been renovated in 2006. A new elastic layer and undersoil heating were also installed when the enlarged pitch was fully refurbished in autumn 2017. The five-time German champions went for LigaTurf RS+ CoolPlus – the world's number one synthetic turf system in professional football with the most FIFA Quality Pro certifications. Top playing qualities are also guaranteed by the use of environmentally friendly EPDM ECO infill granules, which meet the rigorous requirements of the ÖISS (the Austrian institution for school and sports facility construction) guideline for water protection and water abstraction zones. All the other playing fields and the Robert Schlienz Stadium are due to be renovated by the autumn of 2018 in the course of further construction work.