On Monday, 2 September 2019 22:46:21 UTC+1, Mathew Newton wrote:
I need to batten out a block wall to accommodate some 75mm ducting runs and so, given the depth, will effectively be building a stud wall up against the existing wall.

I am wondering how best to secure the top plate given the presence of the joists hangers preventing me from screwing straight up into the joist, and thought about drilling a hole in the base of the hangers to allow me to do this?

To close this one off; I ended up drilling a 5mm hole on the underside of each joist hanger as recommended and screwing the top plate through into the joist above. Everything went well and the frame is now securely in place.

Given that all my drill bits for metal are the ones made of cheese you get in a 1000-in-1 kit for a fiver I decided to 'splash out' on a DeWalt cobalt HSS bit from Screwfix (https://www.screwfix.com/p/dewalt-he...questid=151509) and it was like the proverbial hot knife through butter and no pilot hole was needed.