What are these called?

[hudster]

I'm about to fit a roof window, and I'll need to cut into one rafter and put in some cross pieces so the neighbouring rafters pick up the load.

I keep seeing grey metal fixings which are used where you join one rafter at 90 degrees to the others.

See this pic for example:

What are they called?

 

[joinerjohn]

Look like bog standard joist hangers to me. Personally, I'd just cut the trimming piece to a good tight fit and screw, or nail through from the back of the rafters.

 

[hudster]

Ah joist hangers, thank you!

Not sure if building regs specify I use them or not?

 

[screamer]

Ah joist hangers, thank you!

Not sure if building regs specify I use them or not?

if their on the drawings, they'll need to be used

not sure about england, but in scotland, when fitting a velux, everything has to be doubled up & use joist hangers at all times