On 02/09/2019 22:46, 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?

Here's a picture of the hangers I've got:

http://www.newtonnet.co.uk/permanent/joisthanger.jpg

(Note that this is in another room where I've removed the ceiling,
and where the existing plasterboard on the wall is still in place)

Is there any risk of weakening the hanger by drilling, say, a single
6mm hole in the base of the 'cradle' to accommodate a screw been
driven up into the joist?

Yes, but not in a way that affects the design objective

And screwing something through it mostly restores the strength in that
mode anyway.


--
How fortunate for governments that the people they administer don't think.

Adolf Hitler