With every square foot of London living space at a premium, why relocate when you can extend underground. Ahearn Construction offer full service basement conversions, excavation, construction, new build, waterproofing and fit-outs and. Building a basement is an exciting and rewarding project. For the right property it will represent a sound investment, with the value added to the property significantly exceeding the cost of the work. Whether it is a larger entertaining space you require, a playroom for all your children’s toys and their friends to play in, an office as you plan to work from home more, maybe an annex for an elderly relative or nanny, Ahearn Construction can help you make the most out of your home.