He stops by a sacred banyan tree that rises from a cracked pavement. Its gnarled trunk is girded with colourful votive ribbons. “You can sit here and watch monks filing past on their morning rounds,” he says.

As if on cue, at sunrise saffron-robed monks from a nearby Buddhist monastery appear with alms bowls in hand. “If you come back at 8am, the monks are gone, the traffic is already bad, and the old-town feeling has disappeared,” Davies says.

Dressed in cargo pants and a polo shirt with a knapsack on his back and a pair of sunglasses resting atop his head, Davies, 59, could be taken for a foreign tourist.

Yet he is no casual sightseer. “I know Bangkok’s streets better than my hometown of London,” says Davies, who has lived in the city for three decades.

Right now he is on his way to revisit some of his favourite sights in this part of town. You will not find many of them listed in guidebooks.

First up on his itinerary is a ramshackle double-deck wooden house roofed with rusting sheets of corrugated iron. Propped up on rickety stilts by a filthy canal, it stands within sight of the century-old Hua Lamphong railway station with its arched neoclassical facade.

The weather-beaten house was built some 70 years ago and consists of a simple abode with a shed-like little house mounted on top of it that was once hoisted up there to serve as the second floor, but has tilted alarmingly over time. It is prevented from toppling over only by the residence next door, a boxy new plywood dwelling.

“When I first took a picture of this old house in 2014, there were similar wooden houses all along the canal,” Davies recalls. “Several were replaced in the past six months. In another six months the rest will be gone too.”

His photograph of the wonky old house is prominently displayed in Vanishing Bangkok, his just-published photobook. In it Davies pays homage to some of his adopted city’s little-known and fast-disappearing architectural heritage.

The hardback features a selection of evocative black-and-white images from among thousands he snapped in various old neighbourhoods during his sojourns over five years.

“Bangkok is full of surprises,” he says. “Every time you turn a corner you can find something interesting.”

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For his streetscapes Davies, who doubles as a writer, used a cumbersome large-format Linhof, an antique-style film camera with bellows. It requires careful set-up, can take only a few images at a time, and weighs some 20kg (44lb) with its lenses and tripod.

“Using it takes patience and is hard work,” Davies says. “I threw my back out lugging my gear around.”

He has been rewarded for his pains with exquisite images of a timeless, nostalgic quality. His aim in taking them has been to capture on film, perhaps for the last time, photogenic old buildings and streets that could soon be torn down to make way for glitzy condominiums, hotels and malls.

“That Starbucks is brand-new,” Davies says, indicating a cafe in a newly renovated building among old houses. “It wasn’t there the last time I came here a few months ago.”

Around quaint Bangkok neighbourhoods like this the march of redevelopment has been relentless. Even the area’s picturesque railway station is about to be closed down and turned into a transport museum.

“In many old communities it’s death by a thousand cuts,” Davies laments. “One new building, then another, then another. So much of the new stuff is soulless and homogeneous.”

Not all local residents share his sense of loss over the rapid pace of modernisation. Patcharee Sammasakit, 65, was born in the wonky wooden house by the canal and lived in it for five decades. A bespectacled Chinese-Thai retiree, she now rents a time-worn breeze block shophouse a few metres away.

“Times change,” Patcharee says. “That old building is full of memories for me, but it’s falling apart. There are roaches, ants and rats in it.”

When Patcharee was young, the canal running by the house was still plied by traders in wooden boats selling mussels and other edibles. Its water was clean enough for children to frolic in. These days only hardy monitor lizards venture into its murky sludge of fetid effluent.

Over the years her neighbourhood has become surrounded by congested multi-lane roads and mushrooming high-rises as a bustling metropolis has muscled its way into a once sleepy urban oasis. The community is now home mostly to elderly people, many with Chinese ancestry. They spend afternoons socialising on plastic chairs placed under tattered awnings.

“I’ve known everyone here since we were children,” says Wanchai Nanthakunakorn, 63, who sorts recyclables for a living. “Young people are moving out. They don’t want to live here. When we old people are gone, this area will be redeveloped.”

Davies heads down a street filled with decades-old car repair shops. Here and there, discarded axles and cannibalised engines lie in large heaps on the pavement. He inspects a jumble of car parts with a forklift parked beside it.

“I think it’s gorgeous. It looks kind of sculpted,” he enthuses. “This used to be a hub of blacksmiths and car mechanics. Now, boutique guest houses are opening up here.”

Davies winds up his outing on Charoen Krung Road in the heart of Chinatown. Once called Thanon Mai (“New Road”), this busy thoroughfare opened in 1864 to horse-drawn carriages. It was the first proper road in a city then navigated via countless canals, many of which have since been filled in and paved over.

Running alongside the old road, a few metres off it, is a narrow alleyway flanked by rundown 19th-century brick houses built in a Sino-Portuguese style.

In times past Cantonese and Chiuchow immigrants settled here, working as coolies, hired hands and merchants. Gambling houses, opium dens and brothels proliferated. Many of their descendants earn their living by making and selling a panoply of joss paper items for use in rituals and ancestor worship.

This historic community, called Charoen Chai, is facing the threat of redevelopment. A new station of Bangkok’s subway has recently opened around the corner. As with elsewhere around town, wherever the expanding underground and elevated light-rail lines go, gentrification follows.

“Around new stations property prices go up and many old low-rent buildings get demolished or turned into chic new places for a hip young crowd,” says Chatri Prakitnonthakan, an associate professor at Bangkok’s Silpakorn University who specialises in the city’s architectural history.

“This state-sponsored process of gentrification doesn’t just impact local people. It’s also erasing much of Bangkok’s ambience and historical memory,” Chatri argues. “The government wants to preserve old temples but not the old communities around them.”

A similar fate may befall the 70-plus families who live in Charoen Chai, whose environs boast several venerable Chinese places of worship.

“Our future hangs in the balance. We could be asked to leave any time,” says Phumsith Purithongrat, 46, an ethnic Chinese shopkeeper who sells joss paper and has lived here all his life. “Since the underground came here, things have been changing rapidly.”

Last year a decades-old kerbside eatery famed for its rice curries – which diners slurped down from handheld bowls while sitting on plastic stools alongside a pavement – was forced to relocate from a busy street corner. There is a trendy new Starbucks cafe in its place.

“That old curry shop was part of our life,” Phumsith says. “New things come and old things go. But these new places don’t have the same feel as old corner shops, eateries and street markets. Our old ways of life should be preserved.”

Davies concurs: “There’s great value in preserving this urban heritage. It makes people who they are. It’d be such a shame to lose it.”