If you already have a cellar or basement, then converting it into a new living area is well worth considering, however, if you don’t have a pre-existing cellar then creating one can cost the highest amount per square foot of space compared to any other type of extension and will need to be done by experienced and expert professionals.
Altering an existing cellar may be done without planning permission (you still need to meet building regulations) as it can be classified as change of use, but if you are adding space then it can be seen as an extension and therefore require planning permission – as with any type of major home improvement you should check with your local council before undertaking any construction.
By having the project assessed first, you can find out how much work is entailed in converting it to your proposed use – especially important is waterproofing (tanking or drainage) and an expert will be able to advise you what is needed (do you know how high your local water table is?) in order to ensure your basement conversion is free from water penetration & damp problems. Not only that, you may not have enough headroom in your existing basement and could have to lower the floor level (you need about 8 feet or about 2.4 metres floor to ceiling as a rough guide).
You can then agree a design, sort out any “party wall’ issues, find out what planning permissions & building regulations that need to be met and get a quotation for the cost of the proposed work.
Points to consider
- Lighting & light-wells
- Stairs & access (fire escape)
- Insulation & energy efficiency
- Heating, plumbing, power
- Waterproofing & Drainage
- Planning Permission
Some useful links about party walls can be found here: party-wall-etc-act-1996-guidance