The purchase of Rationalist House was the most significant single advance the Association has ever made. Unlike all the churches, this fine building on Symonds Street in the heart of Auckland was bought entirely from funds raised by members. Most churches get generous handouts from state coffers, lottery grants and so on. Also, they enjoy rates relief on church property. This, of course, is subsidised by the general ratepayer. Rationalists, however, got their building the hard way.

A building fund was established and the end of the Second World War, which grew slowly but steadily. From a total of £315.16.4 in November 1946, the total reached £2121 in October 1950, thanks mainly to some very generous bequests. A considerable portion of the fifties was spent in the search for a suitable building to house the Association. Since the early thirties it had been based in a small office on the fourth floor of the Victoria Arcade in downtown Auckland. Sadly, the history of the Rationalist Association can no longer be followed by visiting the buildings used by them. The Fabian Club Rooms, where the Association met for many years, was pulled down early in the sixties to make way for a blockish and ugly building used by Air New Zealand for many years. And the Victoria Arcade in Queen Street was destroyed in the seventies to make way for a monstrous Bank of New Zealand building that resembles a shabby hatbox.

Over the Christmas break of 1959-1960 two different properties were being looked at unofficially by executive members, but excitement quickly mounted over one on Symonds Street. At a special executive meeting held on January 21 1960 the executive unanimously agreed to consider only the property at Symonds Street and to put in an offer on the building. The asking price was £13,500 but was reduced by £1,000 after negotiations.

Buying the property at 64 Symonds Street required raising a mortgage of £6000 and an appeal was made to members to donate funds. By April members had donated £174, and Mr George Bell, a veteran member from Tauranga gave the Association the proceeds from the sale of a section and pledged himself to bring the total of his donation to £1000. A further £181.11.9 came in through the next few months. Later on further money came in from rental income, but first extensive alterations had to be made. The building was called (not surprisingly) Rationalist House, and had been the residence and medical chambers of the Hardie Neil family since its construction in 1912. Unconfirmed rumours circulated that the Hardie Neil family was mortified that their precious house was being bought by horrible heathens.

An early benefit from the new premises was the home that was finally found for the massive library that the Association had amassed over the years. The large collections donated by William Brabant and Sam Udjur in 1951 and 1953 respectively had had to be stored, in anticipation of space large enough to house what was to become one of the premier collections of Rationalist Material in the world.

The purchase of Rationalist House was a milestone for the Association as it now had permanent quarters and space for rent that could provide an income. Bequests had provided by far the largest source of funds for the Association up until 1960, but from now on that source would be matched, and eventually superseded, by rents. It is a tribute to the tenacity of the members that the building fund had remained operational for fifteen years. The efforts continued, because within four years the Association had freeholded the property. The securing of a permanent headquarters was a remarkable achievement and one that few freethought organisations around the world can match.

Starting in 1994 a series of restorations and improvements transformed the building from a state of disrepair into the fine condition it's presently in. In 1997 Rationalist House was declared a Heritage Site by the Auckland City Council. In 1999 the basement underwent major renovations and now houses the Len Beckett Memorial Library, one of the premier collections of rationalist literature in the world.