When he is first approached he asks the Warden-Commander for 80 to help hire extra workers to strengthen the walls of the Keep (Cost of Doing Business). After this, he offers the quest What is Built Endures, where he asks the Warden to find granite.
If the Warden-Commander finds a Stone Marker in Kal'Hirol, they can show it to Voldrik and his brother, who will report the heroism of the casteless of Kal'Hirol to the dwarves in Orzammar as part of Memories of the Stone.
In addition, he will help clear out the rubble during It Comes From Beneath.
If the Warden pays Voldrik 80 and finds the granite deposit in the Wending Wood, and if the Warden chose to save Amaranthine, in the epilogue it's mentioned that during the siege of Vigil's Keep, the fortress proudly resisted the battering rams of the ogres and the pressing darkspawn horde thanks to the master work of Voldrik. This led to many legends about the keep and its impregnable fame still endures.When Vigil's Keep is restored after the attack, Master Voldrik stood on the walls and declared the defense acceptable. He would never speak more highly of a human building.