Render and steels: finishing off

[ToughButterCup]

Have  look at this : the render (white) butts up against the steels supporting our Wintergarden.

 

 

I have a feeling  (no more than that) where the steels meet the render  (sand and cement coated with three layers of silicon-based paint), that I should  fill the 'joint' with some form of mastic - a bit like putty in a window frame.

 

I think I need to do that because the steels will expand and contract at different rates than the render - and so increase the likelihood of cracked render - and rusting steels.

 

Mastic - yes or no ?

If yes, can you suggest a trade name - or suggest an appropriate type of mastic please.

Edited July 26, 2023 by ToughButterCup