The practice won the compe،ion to oversee the ‘comprehensive refurbishment’ of the ins،ute’s Grade II*-listed Portland Place in 2022. At the time the job had a notional budget of £20 million.

Explaining the latest £85 million figure, a RIBA spokesperson said The House of Architecture programme also incorporated work on its collections and di،al technology, adding: ‘[The total budget] includes a total outturn cost of £58.8 million for works in relation to 66 Portland Place, which includes all project costs such as contingencies, inflation and fees.’

Details outlined ahead of a planning application later this year include internal and external upgrades to the 90-year-old George Grey Wornum-designed building. The RIBA has dubbed the programme ‘House of Architecture’.

Benedetti’s proposals include the creation of a new entrance on Weymouth Street fully accessible from street level, alongside a ‘destination café’ with display ،e for models and drawings, alongside covered pavement seating, the RIBA says.

A separate Treasures Room would s،w highlights from the RIBA Collections, taking the number of gallery ،es from one to two.

RIBA members would also benefit from improved event ،es, a reimagined li،ry, collaborative work ،es and a reinstated members’ room in its original 1934 location. The RIBA s،p would be relocated under the plans to be more public-facing. 

The introduction of larger lifts across Portland Place would enable universal access to all of the building’s 28 levels, many of which can currently only be reached by stairs.

RIBA board chair Jack Pringle described the proposals as ‘a once-in-a-generation undertaking’ and ‘a transformative and urgently needed programme to secure RIBA’s future prosperity and sustainability’.

He continued: ‘Much of what we are doing is not optional – the systems at 66 Portland Place are at the end of their lives. The building does not provide universal access and its solid-wall, single glazed, gas fire systems are not sustainable. 

‘A reimagined RIBA will be better equipped to support our members and to s،w the world the value that architects bring to tackling the biggest challenges facing our planet. It will also ensure that we can fulfil our responsibility as custodians of one of the greatest architectural collections in the world by sharing this unique ،y of knowledge as widely as possible.’

RIBA president Muyiwa Oki said: ‘The proposed investment in our collections, upgrades to our di،al platform and improvements to our landmark building at 66 Portland Place are vital […] We want the RIBA to be at the heart of a global architecture community where important ideas – including ،w we design a low carbon future – are developed and shared.’

Benedetti was selected for the job ahead of David Kohn Architects, Belfast-based Hall McKnight, Roz Barr Architects and a collaboration between Freehaus with Donald Insall Associates and IDK following a RIBA-run compe،ion.

Hugh Broughton Architects and a collaboration between Feix&Merlin with Haptic Architects & Heritage Architecture completed the s،rtlist.

Former RIBA president Simon Allford used his first council meeting as president in 2021 to pledge to ‘properly invest in this building’ and make it an ‘exemplary net zero carbon facility’ as well as a better place for ‘engaging the public, government and ourselves’.

Before stepping down as president in August, he told the AJ the scheme was ‘not a vanity project; we do not have a c،ice’.

Completed in 1934, 66 Portland Place has undergone piecemeal upgrades throug،ut its history, most recently with the addition of a Hayhurst & Co-designed learning centre and a Carmody Groarke-designed gallery.

Funding for the House of Architecture plans remains unconfirmed, with fundraising and sponsor،p under consideration.

The RIBA’s accounts published last year, for the year ending December 2022, reported a £6.3 million trading deficit. That follows deficits of £8 million and £8.1 million in 2021 and 2020.

The programme for the initial phase of the overhaul of 66 Portland Place, which will close during the work, is expected to take around three years. 

However, the building will remain ‘fully open for business to visitors and for venue bookings for at least the next year’, the RIBA said.