At its peak, Peng Chau had eleven lime kilns — a concentration that reflects how significant the island's lime industry was to the wider region. Lime was not a luxury material; it was structural. Construction, paper-making, and other industries depended on it, and Peng Chau's kilns supplied that demand by burning oyster shells, clam shells, and coral to produce calcium oxide. The Sing Lei Hap Gei factory was among these eleven. Its origins lie in the 19th century, though the current building was constructed during the 1920s.

Of those eleven kilns, only Sing Lei Hap Gei survives in any recognisable form. The others were demolished as the island's land use shifted and the lime trade declined. The factory originally comprised two buildings, of which the one still standing is the more substantial. Its survival is partly luck and partly the persistence of the family that owned it, who kept the structure standing even as the business wound down.

The process of lime production from marine shells was labour-intensive and ancient. Oyster shells and clam shells were gathered or purchased, loaded into the kiln, and fired at high temperatures until the calcium carbonate in the shells converted to calcium oxide — lime. Coral was sometimes added to the mix. The resulting material was used in mortar, whitewash, agriculture, and paper manufacturing, among other applications.

This kind of shell-lime production had been practised across coastal southern China for centuries, using the abundant raw material provided by the region's fishing industry. The kilns on Peng Chau were part of this broader tradition. The industry on the island survived longer than might be expected: the kiln kept operating through the Japanese occupation of Hong Kong during the Second World War, a period that disrupted most of the territory's commercial activity. But the post-war development of cement and other modern construction materials eroded the market for shell lime, and by the 1950s the decline was pronounced. The factory finally closed in the 1970s.

For decades after closure, the Sing Lei Hap Gei building stood quietly on Peng Chau, weathering and deteriorating but not demolished. In 2009, the building was submitted to the Antiquities Advisory Board for consideration as a heritage building under the Antiquities and Monuments Ordinance. Heritage status was granted on 20 September 2010 — recognition that this structure represented something worth preserving: not a grand civic building or a colonial institution, but a working industrial site from a largely forgotten chapter of Hong Kong's economic history.

The practical consequence of that heritage designation was financial: it opened access to the Financial Assistance for Maintenance Scheme, which provides funding to private owners of historic buildings to cover preservation and upkeep costs. Without some form of support, many privately owned historic buildings in Hong Kong face an impossible choice between expensive maintenance and gradual collapse. The designation gave the factory's owners a route to keep the structure standing. Today it remains one of the few legible industrial heritage buildings on Hong Kong's outlying islands — a quiet monument to the shell-lime workers and the trade they sustained.