When Javier Garcia-Alzorriz picked up the keys to his first home he was full of ideas about how to turn it from a sad-looking little box into something more glamorous. Alas, he’d spent almost every penny buying the place, so his taste for luxury — encouraged by his job with a high-end interior designer — did not match his budget.

However, with a willingness to get stuck into the DIY and some super-clever spending, he reinvented the one-bedroom flat in a modern block in Harlesden, north London, from light fittings to flooring, for just £4,000.

“It took a year and I worked evenings and every weekend,” says Javier, 28, who came to the UK in 2010 from his native Spain to study at the KLC School of Design at Chelsea Harbour. During the one-year diploma course he was introduced to interior designer Jo Berryman who gave the young graduate a chance and he has since worked his way up from intern to project director and senior designer. As his career progressed, in 2013 he decided it was time to give up his tiny rented flat in Notting Hill and invest in a property.

With savings, plus a little help from the Bank of Mum and Dad, he put down a £25,000 deposit on the £185,000 flat which he chose for its affordability, convenient location and good security. About the only thing the property itself had going for it was good light.

His first project was the kitchen, which was laid out in an awkward L-shape in a corner of the open-plan kitchen/living room. He took down the white built-in cupboards and rearranged them along one end of the room. To increase storage he added new upper cabinets from Ikea and painted them all in City Life, a deep, charcoal blue-grey from Crown’s Fashion for Walls range. He fitted new Buster & Punch handles, and made a glam work surface using sheets of brass he had cut to size and fitted himself.

Mirrors and reflective surfaces ping light around the large living area (Juliet Murphy)

He wanted a mirrored splashback to ping light around the dark space but custom-cut glass was expensive, so he used two Ikea wall mirrors for £60 instead. He then painted the room in the same dark tone as the kitchen. The whole flat is only 475sq ft but Javier said: “The room is west facing, very bright with large windows. I felt it could take it if I had the mirrors and the brass to reflect light.” He painted walls, cornices, skirting and doors the same colour for a streamlined look.

His job helped — a supplier offered him free parquet flooring, which Javier laid himself. A giant mirror was one of several great eBay finds — it cost £150 and he gilded it himself. He also bought a replica Tulip table and old G Plan chairs, now reupholstered in blue cotton velvet. But his favourite piece is the curved retro Fifties bar he haggled over and got for £200 in Marché aux Puces de Saint-Ouen in Paris. It would have cost £300 to ship it home so he searched lift share websites and found a man heading back from France in a family car who picked it up and delivered it for £80.

The highlight of the room is a retro Fifties bar found at a French market (Juliet Murphy)

Javier became an eBay expert, learning that the best bargains were to be had in auctions ending during the working day when most bidders were otherwise occupied. He bought a pair of chrome mid-century armchairs for £17 and as he only had room for one, he listed the spare on the auction website for 10 days starting on a Thursday evening, giving buyers two weekends to discover it and a Sunday night to bid. It made £100.

The small hall is the same blue-grey as the living room, with a gallery of framed family photos on the back of the front door. With Ikea shelving, the boiler room is now a walk-in wardrobe. Marble replaces tatty tiles and is teamed with deep orange paint to give the bathroom a luxe feel. The bedroom is in Farrow & Ball’s Castle Grey at £46 for 2.5L, with bin ends of Porter Teleo inkblot paperas a feature wall behind the bed.

The bedroom is painted in Farrow & Ball's understated Castle Grey (Juliet Murphy)

Bookshelves are Billy shelving from Ikea, spray-painted with a gilt trim, and Javier bought a dressing table from Bluesuntree. Above it, a painting by Moises Ramirez, found on Instagram, cost about £100.

Javier estimates the flat is now worth over £300,000 and he is considering whether it’s time for his next step up.