I've just stripped the shitty old carpet off and I intend to paint the stairs instead. Now I can see the bare steps I've found that the 3 creaky ones have treads that are split across the middle (left to right). Initially I thought it was just an old-age split, but closer inspection from underneath shows they're actually made from two separate pieces placed close together with nothing joining them. As this is the flat of the stair, what would be the best way of fixing the squeak? I can access the underneath. Would screwing a board across the join from below be enough to stabilse the step and stop it creaking?