Inside Rita Konig's smart London house, created by combining two flats into one

Eager to have more room for herself and her daughter, Rita Kong bought the flat above her London home and combined them to create one cohesive space that has all the trademarks of her design, including inventive details, bold use of pattern and a blending of the beautiful and the practical

Upstairs, Rita created two bedrooms and two bathrooms: a lovely large south-facing room with an en-suite bathroom for herself; and a perfectly formed bedroom for Margot with a shower room. Downstairs, the space that was once the kitchen became an indulgent hall-cum-drinks area. It now acts as the main entrance and is reached through the enchanting garden, which was magicked up by garden designer Butter Wakefield. 'This space is such an unexpected gain,' adds Rita, who has papered it in a joyful Japanese-inspired wallpaper by Mia Ray. What she found particularly satisfying about renovating, she says, were the 'small wins'. Her study, created by extending sideways into the bin area, was one of these. 'It's only 7 by 10 feet, but it's a delight to suddenly have a little room where I can hide away and work from home.'

The alabaster pendant light is from Quindry. Vintage Heal's cane chairs with cushions in her 'Ronnie' linen for Schumacher flank a ceramic stool from Rita's mother, Nina Campbell.

Michael Sinclair

When it came to choosing colours and fabrics, Rita admits that it took her a while to get going, but once she did, it was all go. In the sitting room, cigar-coloured linen walls showcase an armchair upholstered in a charming chintz by Rose Cumming and a deep sofa covered in a zebra print. 'I love how the sofa feels quite like 1970s New York and stops the room from looking too serious,' she says. Fabric walls feature throughout and are one of the many 'grown-up fantasies' that Rita indulged. "Terry', a paisley design in linen from her recently launched Schumacher collection, gives her study a wonderful jewel-box feel, while her 'Serena Garland' linen, also part of the Schumacher range, is an elegant backdrop for her sophisticated bedroom. Another wishlist dream made manifest is her tall four-poster bed, draped with crisp curtains and trimmed in a gold linen. 'It's me, inspired by Veere Grenney, inspired by David Hicks,' she observes.

Despite the specialist finishes and fabrics, this is a house built on practicality. Masses of storage has been cleverly carved out wherever possible - hidden behind beautiful batik-patterned curtains in the hallway leading to the study, or on full show in the floor-to-ceiling cupboards that fill one wall of the kitchen and dining room. 'I think good storage can make you feel just as happy and settled as having an extra room,' observes Rita. In fact, the space she is most excited by is the tiny linen cupboard - stacked with neatly pressed piles of her favourite D Porthault sheets - that she has created in the basement laundry room by removing a shower. 'It's a game-changer,' she says.

The opening from the sitting room into the garden room - with a mirrored fanlight added at the suggestion of architect Gil Schafer to give the impression of greater height - frames a view of Rita's 'Chelsea' table for Oficina Inglesa, used for drinks. Mia Rey's 'Ainu' wallpaper, curtains in red wool from Schumacher and an inherited armchair make this an inviting room in its own right.

What always strikes me about Rita's interior design projects is the level of detail. Here, it includes the way she has up-sized the internal doors to create a feeling of generosity and her addition of a dado rail and panelling to the sitting room walls, all of which she has had specialist painted in faux bois. She goes to lengths that many would not even consider. For example, she moved the garden gate to improve the route to the house - a costly decision that ended up with the entire garden wall having to be rebuilt right at the end of the project. Ultimately, meticulous planning and attention to detail have transformed her quality of life. 'What it has done is make everything so much more comfortable,' she explains. 'It's brought me a sense of calm.' And now that it is all finished, she can appreciate that the flat was also great in its previous incarnation. 'I'd just grown out of it,' she says. 'You can't possibly want to live the same way forever'.

Rita Konig: ritakonig.com; @ritakonig