The perimeter joint connets the concrete face slab and the plinth of the CFRD to complete the upstream water barrier of the dam. The main function of the perimeter joint is to maintain a watertight seal against full reservoir load while allowing for anticipated movements between the plinth and faceslab. (ICOLD 141)

There is two type of joint in Dhap Dam. i.e. Horizontal joint connects the Face slab and Plinth and Vertical/Inclined joint connets the faceslab of either side.