How much does a Basement Conversion cost? When budgeting for a basement conversion, you need to decide on what tasks you can do yourself and which will require a professional. Some people will be keen to get the entire conversion carried out by a professional company but this obviously incurs more costs. An idea of the costs involved: Conversion of an existing cellar: 750 1, 400 per square metre; Lowering the floor level and underpinning an existing cellar: 1, 500 2, 000 per square metre; Digging a new basement space and underpinning: 2, 000 3, 000 per square metre The Average Cost of a Basement Hunker How much does it cost to build a basement on a existing. Mar 06, 2016How much will a basement conversion cost? The average cost of a basement conversion is rather higher comparing to other extension projects. It is also a very challenging home improvement projects that require skills and proper planning. I believe it will cost about 1K per cubic meter (according to basement conversion sites) to get the cellar lined, power and lighting installed and made into an empty shell ready for fit out. Aug 10, 2017how much does a basement conversion cost? 10 August 2017 Before you jump into a basement conversion project, its important to consider all the cost implications to ensure that you can afford the necessary work and have it finished to the right standards. The Average Cost to Finish a Basement SmartAsset If you are weighing up adding a loft conversion against converting a basement, it pays to know that a straightforward cellar conversion costs about the same, but creating a basement from scratch is almost twice the amount per m. However, you may be able to create more useable floorspace with a basement than a loft conversion. For example, the cost will depend on the type of property, size of the basement, intended usage, proposed plumbing and electrical services, current floor to ceiling height, access routes and the type of ground. Expect the total cost to be anywhere up to per square metre. Question: Trying to add value to our threebedroom home, we've looked at the cost of converting small attic for roughly 17, 000. Now we've seen an advert for socalled basement conversions. Ground works associated with basement construction can amount to between 18 and 44 per cent of overall construction costs. There is potential scope for cost savings to be made, such as retention of excavated soil on site for landscaping, or adoption of an empty shell specification leading to a reduction in fittingout costs. How much does a basement conversion cost? Jump straight to the section that interests you. Basement conversion costs Planning a basement conversion Designing a basement conversion. Turning an existing cellar into habitable space by tanking and insulating the walls will cost 720 to 1, 800 per square metre around the same as a loft. As with a loft conversion, discounting any of these tasks will likely reduce the overall cost of the conversion. A conversion of a small basement (approx 4m squared) will cost in the region of 11, 000.