Members of the Senedd are returning to the Siambr on Tuesday 24 February after a year long redevelopment project to expand the iconic circular debating chamber in preparation for the election of 36 additional Members on 7 May 2026.
The upgrade marks the most significant physical change to the Senedd building since it opened 20 years ago on 1 March 2006, and symbolises the most substantial development in Welsh devolution.
For the past year, Members have met in the debating chamber in the Tŷ Hywel building behind the Senedd. With work now complete, that space will return to the Senedd’s education and visitor programme, to host sessions for schools and community groups.
Llywydd of the Senedd, Rt Hon Elin Jones MS, said:
“This return to the Siambr marks an important milestone for our Senedd. Our debating chamber has been transformed to meet the needs of a larger parliament and a new era of Welsh democracy as we look ahead to the election on 7 May. This is a building shaped around openness, sustainability and the people we serve, and the changes reflect the next chapter in our democratic journey.”
The Members return to the Siambr to meet in Plenary at 1:30pm on Tuesday 24 February. The first item on the agenda will be the weekly First Minister’s Questions session, and can be watched live on Senedd.tv
Preparing for 96 Members
The Siambr has been expanded to accommodate 96 Members using removable back wall sections that were incorporated into the original design two decades ago.
The redesigned Siambr includes:
- 36 additional desks
- Improved accessibility, with all internal steps removed
- Upgraded broadcasting and ICT systems
The Senedd has been widely praised for its environmental design - designed for natural light, natural ventilation, low carbon heating and cooling, and extensive rainwater harvesting. It holds BREEAM Excellent status and continues to operate with sustainability at its core.
The Siambr expansion honours that commitment by:
- Reusing Welsh oak from original Members’ desks
- Refurbishing and reusing existing oak doors
- Using slate from the same Welsh quarry as the 2006 construction
- Commissioning primarily Welsh-based contractors
The redesign was overseen by RSHP, the architects behind the original award winning building, ensuring the expansion stays faithful to the iconic design.
Ivan Harbour, Senior Design Director, RSHP said:
“Twenty-five years ago, we set out to create an emblematic home for Welsh democracy, with the Siambr at its heart, designed to encourage the public to witness and engage with political life. Today, this sensitive expansion, planned for all those years ago, allows the Siambr to accommodate more Members of the Senedd while preserving its openness, transparency, and the original spirit of participation that has shaped the Senedd’s identity.”
Since 2006 the Senedd has been recognised internationally, including honours such as the RIBA National Award, Civic Trust Award, and the Chicago Athenaeum International Award, and was shortlisted for the RIBA Stirling Prize.
A milestone year
The return to the expanded Siambr comes as the Senedd marks 20 years since the building first opened, and as Wales prepares for one of the most significant elections in its history.
Along with the additional 36 Members, there is a new electoral system and 16 new constituencies which they will represent. On polling day on 7 May, voters will be asked to choose one party or independent candidate to represent them. Six Members will represent each constituency, chosen through a proportional list system.
From 1 March 2006 to today, the Senedd building has stood as a global symbol of Welsh democracy, transparency, and sustainable design. The 2026 Siambr redevelopment ensures it will continue to meet the needs of a modern and growing parliament long into the future.
Learn about the election on 7 May 2026
