I have half-landing stairs which go up 7 steps, around a flat bit, then up another 7 steps. The second portion of the steps is at the back of one of the downstairs rooms, and is currently boxed-in, with storage below. We are hoping to open up the full area beneath the stairs to install a downstairs WC, however there is a pretty substantial timber (~150 x 60 mm) running across the bottom of the boxed-in section.
Any ideas if it would be alright to cut this timber to place a doorway to a WC?
At the moment all I’ve done is chiselled away some plasterboard to see what is going on.