It's not an idiom, it's correct. 'Turning' is perfectly OK as a gerund. 'ing' appears in three places in Engish - as a gerund, as a progressive tense - both of which involve adding 'ing' to a verb, and as a noun-forming modifier for which I cannot find the correct terminology. The latter case involves adding 'ling' to a non-verb to produce a commonly-diminutive noun. Examples include underling, sapling, darling, sidling (which produced the verb sidle as a back formation). It used to be side-ling - i.e. someone who stands at your side as opposed to a subordinate under-ling. But of course given a variety of words ending in 'ing' it isn't always apparent that some were fromed from the 'ling'-route rather than the verbal 'ing'-route. The 'l' is a useful indicator, but not 100% reliable.
Well, it's gone like clockwork so far - all bar the phone line (again) so I may not be able to post much for a bit. Keys arrived, then a van of stuff (including a sofa) which was brought up the stairs by two burly Mancunians. Then a couple of car loads of stuff, followed by a bed, which was brought up the stairs by a burly Edinburgher and further assembled by him. Which was just as well, cos it would have taken us about five hours and we'd have done a really rubbish job of it too. Boxes of stuff still arriving in dribs and drabs, and we're slowly finding places to put all their contents. Nothing's yet come off in our hand or fallen off the wall or ceiling. The heating and shower works, the loo flushes... so pretty smooth so far I would say. I have, however, discovered muscles I never knew I had. Living on the top floor of a tenement block must be good for you, surely.
[rab] Good luck an' all in your new home. The loo *might* flush, but just check it. My mother discovered the loo in her new bungalow flushes with water from the hot water system. (Have I mentioned this before?)