Obviously, this waterstop function is very limited as the only barrier to migrating fluids is the adhesion to the concrete and compression of the mastic waterstop product within the joint. For this reason, mastic waterstops tend to be more effective in construction situations where large concrete loads are applied on top of the waterstop such as wall on footing or burial vault lid, and far less effective when installed in vertical applications such as a wall joint.
Mastic waterstops are the lowest performing of any commercially available waterstop and are price accordingly, being the lowest cost waterstop as well. Because of the low cost and ease of installation, mastic waterstops are the favored products of commercial constructors and home builders.
Excerpt From: David Poole. “The Little Book of Waterstop.” Waterstop King, 2013. iBooks. https://itun.es/us/Ngg6J.l