Since there is no grout in the Proto II™ post tension retaining wall, water flows freely through the wall. Drains, weepholes, or tongue and groove units may be used. Just one cubic foot of gravel behind drainage is required at intervals stated in the product data sheets.
 

	Drain installed.
Weep holes or mortarless head joint (tongue-and-groove) cmu.

The draining capabilities of the non-grouted Proto II™ retainer allows the end user the option of eliminating waterproofing of the soil side of the wall.