I have a solid block wall 900mm in width with a sink on it and all pipes are revealed. I am doing up the room and would like to conceal these pipes. I was planning to build out the wall by 3 inches, which will cover all excisting pipwork. My plan for doing this was to use 3.5" by 1.5" studwork and attach this to the block wall horizontally at the top, bottom and middle and twice vertically at thirds. I was then going to sandwich a second length of studwork to each of these to bring them up to 3". Then plasterboard to that frame. Is this an acceptable way of doing this or should I be building a full stud wall for this purpose?