hen I see an old but perfectly usable building being pulled down in my native Lahore, it hurts me deep inside. It hurts because, on the one hand, the city loses a bit of its character, and on the other, I have always wondered what becomes of the debris. Since most of it cannot be reused, I suspect that it ends up in the soil. Cement concrete does not decompose.

On a recent visit to Copenhagen, I saw a remarkable way of putting old buildings to reuse. Nordhavn (North Harbour) on the northeastern edge of the town was an old complex of piers with warehouses, grain silos, hostelries and other buildings that make the usual adjunct to ports and harbours. In this complex Orient Kaj (pronounced Kai, the same as the English quay) was the pier that sent out trading ships bound, as its name suggests, for the Far East.

Most of the buildings in Nordhavn are old, dating back to the Eighteenth Century, a time when the lure of India and the East Indies ran high and maritime trade was the way to go. Other buildings were added in the following century. Time went by and over the past one hundred odd years with changing modes of transport, the once bustling Orient Kaj whose skyline was dominated by the masts of sailing ships and later by smokestacks on steamboats, slid into dereliction. In recent years, much of Nordhavn and especially Orient Kaj became a seedy, run-down district where nobody wished to live.

About 2005, the city government of Copenhagen set out on a plan to rehabilitate the almost abandoned district of Nordhavn. Work began in 2009 and for the next ten years, the area of Orient Kaj was a large construction site. Happily, no building was pulled down. They were all massively refurbished.

To emphasise Nordhavn’s centuries-old connection with the sea, new canals and a marina were laid out. Warehouses and crumbling hostels were turned into office blocks but the most spectacular effort was the conversion of four-grain silos into apartment blocks.

Two of these silos had the rectangular shape of regular buildings while one pair was of traditional cylindrical shape rising to fifty-nine metres above the ground. Despite a major civil engineering job needed to reinforce these, converting the former was not difficult. By 2017, the two rectangular were aesthetically pleasing apparent blocks with balconies and windows all around to catch the sun. One of these has a rooftop garden. The other is topped by a glass-clad penthouse restaurant.

The cylindrical silos, however, needed some truly masterful structural engineering. First off, the structures needed reinforcement to withstand the weight of six floors of housing. Then, at a little over twenty metres above ground, rectangular openings were created in the structures to thread in massive steel cantilevers. These were anchored in the empty belly of the silo. Above the cantilevers, came a platform on which the apartment buildings rested.

Places like Model Town and Gulberg in Lahore have lost some priceless instances of residential architecture and art deco houses from 1920s to early 1950s.

Today, with their shiny blue and white panes, the circular apartment blocks present a very pleasing sight and it is difficult to imagine that until 2009, rats the size of house cats skittered around the floors of the silos foraging for bits of grain left over from a hundred years ago. Unsurprisingly, Orient Kaj is now a coveted residential area interspersed with office blocks.

And what do we do in Pakistan? We acquire an old property in, say, model Town of Lahore and tear it down regardless of the law enacted in 1973 declaring any seventy-five-year-old building protected. No questions are asked; neither the law-breaking new owners nor officials who turned a blind eye to the destruction of heritage are penalised. The result is that in the past three decades places like Model Town and Gulberg in Lahore have lost some priceless examples of residential architecture and art deco houses from the period 1920 to the early 1950s.

The first thing to get the axe, literally, is all the trees that once adorned those large plots. Since most end up as fuel wood, the untold amount of carbon sequestered in their timber goes into the atmosphere to create the greenhouse blanket. And since no photographic record exists of those old houses, students of architecture are deprived of the study of our housing styles of the past.

In Karachi, some thinking minds did well to preserve a Raj-era building in Kharadar. They carefully documented it in precise detail and numbered each stone block before dismantling those systematically. The material was then carted to Clifton and the entire building was rebuilt to become the Indus Valley School of Art and Architecture.

So far as I know the only example of an old structure put into reuse by an individual is one outside Lahore near the village of Laliani in the Kasur district. Once a poultry shed, in the middle of a four-acre tree-shaded spread, it was very tastefully turned into a conference hall – or a wedding hall if you wish.

As the Danes boast in Copenhagen that they have turned Orient Kaj into an environmentally-friendly area, so too was this old poultry farm by the simple act of not cutting any of the old trees. Instead, the owner planted over four dozen new trees, all of indigenous species. It is today known as Cholistani because the owner, Akhtar Mammunka, is a man of the desert.

Closer to the Orient Kaj model is the remarkable work done in restoring a number of two to three-hundred-year-old buildings inside Delhi Gate in the Walled City of Lahore. Overseen by the Aga Khan Cultural Service, it needs to be replicated elsewhere in Lahore and other cities.

Copenhagen is a long way off, but it is a city that has kept itself alive by preserving its architecture. Some of those priceless buildings go back more than four hundred years and still being in perfect fettle are in use. Rather than cut our connection with our past, we need to duplicate the few endeavours that we have seen in Pakistan. The architects of tomorrow deserve to know what we once had.

The writer has authored several books and is a fellow of The Royal Geographical    Society. He tweets @odysseuslahori