When the only way is down
In London, super-basements are no longer the preserve of the super-rich, and are seen as just another form of extension. Will we see them here?
On the corner of Merrion and Shrewsbury Roads stands Shrewsbury House, a substantial red-brick pile that was once occupied by the Belgian Embassy. Bought in 2014 for €6.5m by Owen Killian, the CEO of Aryzta, the property then had 604 sqm of accommodation and was reported as being in need of refurbishment.
Commuters who pass the property on their morning crawl into the city centre will have observed the on-site crane and other evidence of the substantial building programme being undertaken by the new owner. Killian secured planning permission to more than triple the floor area. Most of this extra space will be in a double basement, which will house a car lift and car park, a 17m swimming pool, a home gym, and a 91 sqm log store.
When the work is finished, Shrewsbury House will not only be one of the largest private houses in the State, but will also be one of Ireland's first 'iceberg' houses.
Super-basements have become de rigueur in affluent areas in London and other densely populated and constructed international cities where space is at a premium. Initially the preserve of oligarchs and potentates with seemingly limitless funds, and often the trigger for bitter disputes between neighbours reported gleefully in the Daily Mail, the trend has trickled down to such an extent that it is now commonplace for there to be several super-basements under construction at any one time on relatively modest streets of four and five-bedroom terraced houses.
On visits to stay with friends in Notting Hill, I have had the pleasure of being woken up every weekday morning by the sound of drilling reverberating through the air from multiple locations. My hosts tell me that they have gone from being cross, to being resigned, to thinking that they might do one themselves on the basis that if you can't beat 'em you might as well join 'em.
Other London friends have been so disrupted by the basement builders that they have formed residents groups designed to frustrate their neighbours' plans. And Kensington and Chelsea has curtailed the scale of basement construction permitted in the Borough - homeowners will in future only be granted permission for single basements rather than the double behemoths that have prevailed over the past few years.
Design consultant, Helle Moyna of Nordic Elements, came into direct contact with the super-basement phenomenon when she lived in London and her neighbours - who had what she describes as "an ordinary Victorian house on an ordinary street in Clapham" - decided to embark on one.
"In London it's what people do once they've extended; it's cheaper than moving. It was eight years ago, and the drilling was unbelievable, I had just had a baby and I used to go out and walk the streets to get away from it. They ran into an old Victorian water tank filled with concrete and the vibrations were so severe that they cracked our marble mantelpiece and slate hearth. They were very conscientious neighbours though, and they even offered us their house in Brazil to stay in while the work was being done!"
Moyna holds no hard feelings for her neighbours and their project.
"In London you just have to accept it. We had built up and out and back, at the end of the day we might have wanted to do it ourselves. You have to remind yourself that it's not going to go on for ever, even though at times you might feel as if it will. They are still being done on every other street in Clapham, but that's because the property market in London is crazy. There just isn't the housing stock. A lot of the madness has to do with the school system; you want to stay put if you have good local options. In our neighbourhood there was a new academy that was very good and people decided to stay in their houses, it put the brakes on people who would have moved otherwise."
In the end, Moyna's neighbour regretted having embarked on the project.
"She said that if she had the decision to make over again that she wouldn't go ahead. She did it to make a big room for her boys to play in, but boys need outdoor space, and there's only a short period of time when you are stretched for space before they head off to boarding school or leave home for university. In the long term you have to ask whether it's worth it. We thought about it ourselves and were told that it would cost a minimum of £250,000. If you add in extras such as extra height and light wells then the costs go up. My neighbour opted for 2.4m ceilings rather than the standard 2.2m, and light wells in the floor and ceiling of the side extension over the basement to bring in more light."
Moyna's friend Rory O'Neill of MyPlumberMan is also based in affluent south-west London and has worked on numerous super-basement projects over the past 12 years since he established his business. He says that the cost of property in the area makes super-basements a no-brainer for homeowners.
"In London it's all about the square footage and there's a calculation to be done. If property is selling at £600/700 per sqm and a basement costs £300/400 per sqm then you're almost doubling your money and getting a 40/50pc return. They are generally used for teenagers, so the house divides in two. Houses that have already done the side and the attic, and then do a basement, have grown by 150pc since they were built originally."
Not surprisingly, there are multiple specialist basement companies in London that have cropped up to service the seemingly insatiable demand for more space.
"They come and give an initial assessment, and the dig out takes anything from 12 to 30 weeks," explains O'Neill. "It's done a square metre at a time, and the underpinning happens as they go. Amazingly, I think there has only been one fatality, when a whole house collapsed into the hole.
"The whole area is then tanked with a membrane and large pumps pump out all the water to the drain - that's all that a lot of basement companies do: they create the shell. Then the second part is the fit-out. These specialist companies have got very good at it; there is a huge emphasis on keeping things neat and tidy and not interrupting traffic and parking with skips more than is absolutely necessary. It used to be a bit hit and miss and now it's sharp and aware because of the potential for complaints from neighbours. As time has gone on people have become more prepared to spend what is necessary to do it correctly."
O'Neill's involvement usually comes once the shell is completed and before the fit-out. "I install underfloor heating across the whole footprint; it's like going in to a new house so it's quite easy to work in. And if a house gains 30-40pc in size then the existing boiler is not going to be powerful enough, so it demands an overhaul of the whole system." It is not for the faint-hearted.