AAC Block Jointing Mortar is a non-sag, lightweight mortar that provides for an easier installation of AAC blocks. AAC block is a one-component mortar that sets and hardens quickly and easily. Magna Green AAC Block Jointing Mortar has a High-Strength & quick firm lay of joint with AAC Blocks. Our Joint Mortar has a First Class fire rating and is easy to clean. Block Jointing Mortar durable and strong product that does not shrink, crack or deteriorate over time.