The reason you have to consider the potential for defects is it is not possible to expect 100% of staff to work 100% perfectly all day every day, so defects do occur. If a leak occurs after the basement is finished you need to be able to deal with it without causing damage to the internal finishes.
If the waterproofing is just on the outside or is integral to the structure ( additives , sandwich systems ) then it cannot be accessed and repaired.
Considering the form and feasibility of repair would always lead to the need for a cavity drain.
A cavity drain system is the only aspect of the waterproofing that can be guaranteed to work because it can be accessed and serviced or repaired if necessary.
This is of course if it has been installed correctly and to a design that allows for full serviceability. so often this is not the case because designers are not experienced with the potential problems and so do not know how to design them out.
Preventing water penetration is the first and primary concern. Basement waterproofing is often installed on the outside so the design has to take into account the management of the installation so as it can be installed correctly. Problems occur because of weather conditions, piecemeal installation, damage on completion. This can all be designed out by an experienced contractor.
The key words here are experienced and contractor.
A supplier can only design with their own materials and will not accept any liability for the final installed product or design. In the event of a failure they will simply say it is an installation problem which it probably will be.
Suppliers will be experts on their materials but for the most part will have no experience with on site installation.
It has to be the contractor who designs, supplies and installs the waterproofing.
All designers should have PI for waterproofing and cover the whole project with products insurance. MacLennan do.
To find out more book a seminar. I am happy to visit at your premises and present for an hour or more on all aspects of basement and deck waterproofing design.
– Ian MacLennan