First off, there’s something of a “me too” effect here. People in London who have heard horror stories and therefore been reluctant to undertake a basement conversion, see their neighbour’s cellar conversion before and after the work has been done. The next morning they’re looking for a company which can handle a similar project in their house.

Shortage of houses increases “stay put” trend

The “stay put” trend is partly the result of a stagnant London property market in which people either can’t afford to move, or have the finance but find there is little on the market that appeals. In these circumstances, staying put and creating more space is a sensible alternative, especially given the extortionate stamp duty sums payable on London properties.

And although a basement or cellar conversion is a major expense, the cost can frequently be added to the mortgage, and will add up to far less than the cost of buying more space by moving house. That leaves more equity in the householder’s hands, and may actually drive the cost of their borrowing down compared to taking out a much higher mortgage for a new house.

Of course, the trend for staying put and digging down actually adds to the market scarcity of good houses, so to some extent, it’s going to be a self-reinforcing phenomenon. Fewer houses for sale, more owners opting for a basement or cellar conversion in London boroughs.

But what are they putting down there? The man cave seems to be rising in popularity, with children’s playrooms and TV rooms also high on the list. Basement conversion companies can be very creative in the way they get light into a basement but if it’s not possible to have much natural light, people choose to use the space for activities that don’t need it.

The new living space can improve the ground floor too

For example, a utility room in the basement or cellar means that the washing machine, tumble dryer, ironing board, airers and even the freezer can all go downstairs. This can create more living space upstairs, giving room for a viable eating space in a previously cramped ground floor kitchen.

The space can also be integrated with the new basement – for example, a door or french windows in the newly created ground floor kitchen space can have steps down to an area taken from the garden, which does allow light into the basement. So it’s important to discuss basement or cellar projects with a company that has done a lot of these conversions, and has the specialist design skills to take an integrated view, in which they consider the potential of the new basement for improving the use of the existing ground floor space.

The best approach is to consider the scheme as a whole, rather than as separate parts and to get a reputable company, such as Noble Structures, to come up with some ideas for you to look at.