I completely agree. Processed Steel has increased 14% in last 12...

I completely agree. Processed Steel has increased 14% in last 12 months, concrete 8%.
My plumber now needs to use stainless over copper for pipes greater or equal to 75mm due to lack of supply / cost efficiency.
Must say, looks fantastic.
labour has also increased in the form of contractor margins due to recent demand to secure labour) but that is short lived as soon contractors and builders alike shall be seeking work.
but in context (suggesting capex would have been around 1b), 3-5% of overall cost for inflation on some construction materials I would consider reasonable
remember, engineering/design/authority fees/mgmt fees/bank fees/ rates / general prelims / excavation, site establishment etc etc will remain unchanged.
for these reasons, in my humble opinion I believe 3-5% overall would be a reasonable addition for capex