Whatever you need to extend for, if you live in a city your options can be limited. You won’t want to lose any of your precious outdoor space to a conventional extension, and planning restrictions may prevent you from converting the loft.
It’s no surprise then that many people are opting to extend downwards. This may mean converting an existing basement or cellar into habitable space, or excavating a completely new one.
The iceberg effect
While it’s possible to go completely ‘iceberg’ and have more of the home below the surface than is visible above, most people looking for a basement conversion in London are likely to opt for something more modest.
Creating a basement is expensive, so you have to think carefully about the value it will add to your home. This applies both in monetary terms and in terms of usability. Will it make the property a more practical or attractive place to live? Partly this depends on the use you want to make of the new space. Gyms, cinemas, offices and teenage dens all add practical value, but swimming pools and saunas perhaps less so.
Things to consider
Before extending into the basement there are a number of things you need to consider. First of all you must ensure that the property is suitable. Most planning authorities now frown on basement conversions that go down more than one level or which extend to more than half the area of the garden.
You also need to consider whether the area is suitable; the water table and drainage are key factors here as well as the position of any underground services like gas and sewer pipes that may need to be avoided or re-routed.
It is worth finding out if any neighbouring houses have already converted their basements. This not only gives you an idea of what is possible, but it indicates how likely you are to get planning permission for the project you have in mind. If you and your neighbour are both thinking about converting your basements it’s also worth investigating whether you can perhaps save costs with a joint project.
It follows on from the above that you do make sure that your neighbours know what you’re up to. Converting a basement will lead to some degree of noise and disruption, so don’t leave next door to find out your plans via a letter from the planning department. Pay for a party wall surveyor to allay any fears they may have about possible detrimental effects on their property.
People often fear that basements will be dull and gloomy but that needn’t be the case. Modern architectural techniques like light wells or light pipes can bring in natural light so you’re not relying entirely on artificial lighting. You can bring in light from the rooms above too with options like open or glass staircases, which can make a basement feel spacious and airy.