Can you tell me the name of membrane I need to use to cover groundwork for my foundation

Depending on the requirements of your local council there is a protective membrane called Bituthene 8000. Its not cheap and its generally only used in areas where flood levels are a risk, It can be used horizontally or vertically to protect basements and other critical sub-structures from the effects of hydrostatic pressure, ground contamination, proun to floods/dampness or gas penetration. If there are no risks of any of the above then just a good quality, heavy duty plastic membrane will do the job.

Visqueen 2000/3000