Double sided tape
This is for use for sticking the various waterproof membranes in place.
3M 9589 Double sided tape. Half inch width is about $10 per 100 foot reel.
Other wider widths are also available (but half inch will be fine).
The following 2" wide double sided tape seems to work really well, even on polyethylene sheet...
Double Sided Adhesive Carpet Tape by DigHealth(TM), Pack of 2-(2 Inches x 30 Yards, Heavy Duty, For Indoor Outdoor Carpet Edge Binding, No Residue), Removable Carpet, Mat, Rug Cloth Tape
or more expensive...
XFasten Double Sided Carpet Tape, 2-Inch x 30 Yards $17.98 for 90 feet (but brought for less on offer)
Another possibility is SIGA Twinet double sided tape available from email@example.com. A 50 yard reel is about $40.