Beginner’s guide to Basement extensions
If you’re outgrowing your home, the best solution for adding space could be to extend down - Emily Smith investigates what’s involved
Fraher Architects added extra living area to this house by digging down. Sunpipes and rooflights bring natural brightness to the subterranean level
JOCELYN LOW
There are many reasons why people choose to dig down rather than extend horizontally. If you have a large garden in a rural location, then maybe a subterranean level isn’t right for you. But if you live on a tight plot in a built-up area that can’t accommodate a conventional extension, or already suffers from overlooking, excavating to create more space could be the best solution. Here are the main considerations for building down.
Potential complications
The thought of excavating a large hole under your property might sound like a recipe for trouble, but the reality is that adding a basement could actually increase the structural stability of your home. “Many historic properties were built on poor ground, with badly designed foundations that aren’t in line with today’s standards,” says Neil Dusheiko, Director of Neil Dusheiko Architects. “Some older dwellings might have suffered from damp and settlement because of their grounding.” Geological surveys and soil tests can be used to establish the conditions beneath a house, which should be fed into your structural engineer’s drawings. They should then produce a construction method statement that details the design of the new basement, foundations and waterproofing, as well as how work will progress on site. “If the condition of the building is sensitive, the contractor should set up monitoring stations to check if any movement is taking place due to the works,” adds Neil.