Brazilian firms Hype Studio and Santini & Rocha Arquitetos have added a lightweight roof with a leaf-shaped structure to the Beira-Rio Stadium in the city of Porto Alegre ahead of the 2014 FIFA World Cup, which kicks off on 12 June (+ slideshow).

The Beira-Rio Stadium was built in 1969 as a home for football club S.C. Internacional and renovations were already underway before Hype Studio and Santini & Rocha Arquitetos were engaged to oversee the project and ensure its completion in time for the World Cup.

Fans had requested that a roof be added and suggested that the stadium's infrastructure needed modernisation. In addition to the roof, the architects removed and replaced the concrete lower tiers, installed new VIP facilities, and upgraded plumbing and electrics.

The steel roof structure that extends above the stands, ramps and turnstile areas replaces a previous solid roof that only covered parts of the stands.

A PTFE membrane with transparent sections between the main structural supports allows daylight to filter through to the stands and creates an unbroken surface that reduces heat absorption and results in a uniform temperature inside the stadium.

The roof is also self-cleaning and channels rainwater to tanks from which it can be used for flushing toilets, helping to reduce the stadium's water consumption.

Four existing ramps have been preserved and now lead to circulation areas that extend around the entire stadium and provide access to catering and retail facilities.

Seventy suites have been added, along with a museum, media room, shops and 14 towers that connect all levels and have been designed to enable the stadium to be evacuated within eight minutes.

The new capacity of the stadium has been reduced from 56,000 to 52,000 and the pitch has been upgraded with improved turf and drainage.

The stadium was inaugurated by Brazilian President Dilma Rousseff and FIFA Secretary General Jerome Valcke and will host five matches during the tournament.

Photography is by Marcelo Donadussi and Gabriel Heusi.