I want to convert my cellar which is 8.75m x 4m. It already has a solid wide staircase, hallway and 3 separate rooms which are perfectly configured for my intended purpose - 2 bedrooms and a bathroom. There are also 2 large existing lightwells with windows in the potential bedrooms. 65% has good head height (2m), but one room needs digging down by around 30cm to achieve the same.
Paperwork and books have been stored in the basement on open shelves with no ill effect (other than dust), for years. I've had quotes to convert it of around £30K, but do I need to pay to have a completely dry basement tanked/waterproofed in order to use it for accommodation? Installing electrics, heating, new doors, windows, plastering, cosmetic work and a bathroom would cost less than £15k. Can anyone advise me?