The age of the stone shed is hard to determine. We know that Henry and John Williams had a trading store situated somewhere near the stream at Horotutu, from the 1820s. The store is shown in a sketch map drawn by Edwin Fairburn. It is likely that building was no longer in use as a trading store after Henry Williams moved to Pakaraka in the 1850s
We also know that Hugh and Lydia Carleton had a house built on the site that Canon Percy Williams would later purchase from the Church Missionary Society. They were married in 1859 and occupied a stone-walled house at Horotutu.
An 1859 water colour painting by Thomas Hutton, (who was married to Lydia Carleton's sister Sarah), shows Henry Williams son Henry's house at Horotutu along with another house and another small building approximately where Williams House and the stone shed is today.
There is also anecdotal evidence that a school for local children was held in the stone shed during the 1880s. Who the teacher may have been remains open to conjecture.
Taking all this into account it would be reasonable to surmise that the stone shed is between 130-190 years old. One thing for sure is that it is the oldest, still-standing building in Paihia.