Most failures are due to bad design and installation by non-specialist contractors The minimum requirement for a waterproofing specialist is

• Design, supply and install all waterproofing systems. No split responsibility.
  
• Take full responsibility for waterproofing Basement walls, floor and roof.
  
• Accept design liability and have Professional Indemnity insurance (unlike any manufacturer).
  
• Give insurance backed guarantees of up to 20 years.
  
• Provide an insurance backed products guarantee for consequential damages. (Not to be confused with guarantee protection insurance )
  
• Ensure compliance with all relevant standards.
  
• Comply with all relevant health and safety requirements.
  
• Do not use sub-contractors for specialist work, only their own fully trained staff.
  
• Must be able to provide references for numerous similar projects.
  
• Be able to accommodate project time constraints.