He was a founding partner of architectural firm Douglas Wallace Consultants.
In a statement on their website said: “It is with deep sadness and shock that we share the news that our beloved Hugh Wallace. We are heartbroken.
“His passion, creativity and warmth touched colleagues, audiences, and friends across the country.”
Taoiseach (Irish prime minister) Micheál Martin said he was “deeply saddened” to hear of Mr Wallace’s passing.
Martin said Mr Wallace’s “advocacy for good architecture, coupled with his wonderful communication skills, performed a wonderful public service”.
Tánaiste (Irish Deputy Prime Minister) Simon Harris said her was a “character larger than life with a booming voice who made such an important contribution to Irish life by providing entertaining programmes but also in teaching us the importance of restoration and architecture”.