I am sorry to bring this old thread up!
I have been looking through the old threads and cannot find a definative answer on SWA in cavitys.
I have really struggled to find a cable route for a sub supply and ended going into an existing hole in a cavity wall at ground floor ceiling level.
I have then pulled this up into the loft.
How bad is this?
i dont think its that bad to be honest. ive seen SWA buried directly in concrete, ive seen it smothered with lagging in a power station, and left loose in cable pits, constantly submerged.
it wouldnt be my first choice for a route, but if i was stuck, then i would consider. at least its mechanically protected