The sea and coastal activity around the Forty Foot in Sandycove is something many Dubliners take for granted, be they active swimmers, passive paddlers or any one of the tribes of hangers-on who rarely wet more than an ankle.

It is a vibrant place that is free for almost all to enjoy and on hot summer days it’s a favourite haunt for teens eyeing each other up like an aquatic version of West Side Story.

Surveying all the activity is the stone fortress of a Martello tower, now the James Joyce Centre, founded by acclaimed Irish architect Michael Scott and friends. Scott bought the tower, now a landmark protected structure, in 1954. With financial assistance from film-maker John Huston, he and his friends founded the James Joyce museum which was officially opened on Bloomsday, June 16th, 1962 by Ulysses’s first publisher, Sylvia Beach.

Scott’s own house, Geragh, designed in the style of an ocean liner, is another architectural gem and both structures contribute to this corner of Sandycove being an architectural conservation area.

Nearby is 12 Sandycove Avenue North, a very fine five-bedroom family home secreted behind electronic gates.

Built in the brutalist style, it sits on half an acre of grounds and has direct access to the swimming spot via a pedestrian gate on Sandycove Point. Its bands of render, glazing and marine-grade aluminium were designed to echo the lines of Geragh, explains Ger Crowe, associate director at architect firm Extend.

Constructed in 2014, it is is set over three storeys on a plot formerly occupied by a house called Rockfort. It was sold in 2010 for €3.1 million and then returned to the market in 2013 seeking €3.75 million, this time with planning for the construction of the new property. The existing house and mews was to be demolished and the new design given a 180-degree spin so that the main entrance now faces Sandycove Avenue North, a warm and welcoming south-westerly aspect.

It is listed as having sold for €2.75 million in August of that year, according to the property price register.

Based overseas, the new owners wanted a design that would link the building to the garden and also work as a family home. While the main living areas all have glass walls, it feel like a very private setting.

It’s roomy too, extending to 487sq m (5,242sq ft), with a layout very much suited to family life.

The property opens into a large double-height hall with a private home office to the left. Off here there’s an adjoining guest toilet. So far, it feels like a run-of-the-mill home.

It’s only when you step into the main living space that there’s a real sense of what’s on offer. Poured concrete floors the mainly double-height space, which comprises a kitchen with other living areas radiating from it.

Featuring units by Deansgrange-based Agata Design, the eat-in kitchen has a waterfall countertop of raw concrete. The deep slate-grey cupboards and broody-hued floor contrast with wavecrest-coloured counters and splashback, a subtle way to reflect the briny surroundings. Two doors about 6.5m high open to a wraparound tiled patio in a slick pivot.

When you want to escape the expansive ceiling height you can retreat to a dining nook, complete with floating concrete seats and day-glo yellow walls and ceiling. It’s a fantastic slice of privacy for morning grouches when the broken-plan layout might feel too expansive.

Jutting out in a peninsula form is a family-cum-dining space which can be screened off with soft-sliding pocket doors. To the left is a step-down conversation pit-style living room.

Hidden from view are rear rooms that include a pantry with laundry chute, utility, gym, plant room and a boot room at the side entrance.

The house is gas heated and features rooftop PV panels to heat the water, a mechanical ventilation heat recovery system and a rainwater harvesting system with an underground tank which pumps water to the bathrooms. The property also comes with an already constructed lift shaft to future-proof living there. The Ber is B2.

In the triple-height hall an open-tread staircase leads to the first floor where four double bedrooms radiate off a large landing, big enough to accommodate a full-size ping-pong table.

This is where the children’s rooms are located and these are painted in subtle homage to the sea: restive blues and watery greens. Two of the four doubles have ensuite bathrooms, while the other two share a Jack-and-Jill washroom.

Here the floors are richly grained engineered wide-plank walnut. There’s also a second home office with views across the vast expanse of Dublin Bay.

This floor has access to not one but two terraces, giving southern and western light; through the trees you can see across Scotsman’s Bay to Newtownsmith and the piers in Dún Laoghaire.

On the second floor is another sittingroom, one with access to the largest of the property’s three terraces – a real suntrap.

It leads through to the main bedroom, which has a light-filled ensuite that is ultra-private thanks to Luxaflex blinds. From the free-standing slipper-shaped bath there’s a view to the obelisk on Killiney Hill.

A clever consideration is the guest toilet featuring a chartreuse yellow sink.

Set out in lawn, bounded by granite walls and watched over by the Martello tower, the garden is very private.

Number 12 Sandycove Avenue North comes with a sizeable car – or even boat – port, and it is seeking €5.5 million through selling agent Lisney.