Neil Porteous explains:
This is an 18th century lime kiln, but castellated to look like a medieval structure.
Lady Mairi had a wooden shed placed on top and used to do her homework there as a youngster.
You often find lime kilns by water because the limestone was heavy.
There were often derricks on top of the structure to lift off the stone and deposit it down into the kiln.
The process is like charcoal burning, controlling the amount of oxygen drawn into the kiln and depending on the fineness of the grade of lime required may take many days say for plasterers lime or a lesser time for agricultural lime.
The lime kiln probably dates from around 1784 and was a designed feature of the demesne.
The whole Sea Plantation was reclaimed from Strangford Lough, its sea wall and peripheral walk would provide views of the Lough.
The canal which held all the drainage water when the tide was in and released it into the lough by means of a non-return valve a pier for mooring yachts and rowing boats and a boat-house; then you would return by the Clay gate lodge and thence on to the Temple of the Winds.
Beyond that there is a faux chapel as well as real archaeological remains ~ the Gothic cow byre; the cromlech; the ruined abbey; and a Motte-and-Bailey from Norman times.
The idea was to provide curiosities, all of them Gothic in design.
They were laid out by William King, of Dublin, Ireland’s answer to Humphrey Repton.
It is one of his very early commissions and is significant in that the estate is intact and unspoilt.
Charles Villiers continues:
I saw one of your readers has inquired about the building near the Mount Stewart swimming pool: I can supply some information about the one with the "Gothick" windows and traceries.
Whilst I do not know why it was originally built - in, I suppose, the early 19th century - I do know it was adapted in the 1930s with a staircase; the pouring of a concrete floor foundation on the roof; and the construction of four stone columns to support a wooden summer house; completing this substantial superstructure on the old building for the benefit of my late grandmother [Lady Mairi Bury] when she was in her "teens".
My grandmother used it for her studies on warm summer days and to entertain her friends of her own age nearby to the swimming pool, as somewhere separate from the adult gatherings at the swimming pool itself in the 1930s.
My grandmother's siblings were all much older, so her parents gave her the summer house so she had somewhere fun to entertain the numerous friends of her own age who were invited over.
It is obviously sad that this elevated summer house, and the older building which is underneath, is now largely obliterated - like every other building in and around the swimming pool of Mount Stewart, where so much fun was had by so many for around 50 years.
I believe some mindless moron decided to smash the Gothick window surrounds of the old building with a sledgehammer.
First published in May, 2012. Revised in 2014.