[BobL]

“Anyone in construction here?”

Yep, with concrete we require at least 1” of concrete FULLY surrounding rebar so as to prevent water from reaching the rebar and thereby (of course) causing the rebar to rust. Rebar gives concrete its tensile strength (concrete has excellent compressive strength without rebar), so take away the rebar, and any tension (pulling) on the concrete and it will fail.

At least that was the case when I managed major construction projects many years ago - cannot see why it would be different now.

I have NO CLUE as to why this crap was permitted in the UK, other than they may have had a Labor government at the time.

[maro]

Probably because it was cheaper.

[RandFan]

Thanks for that. Just reading this article/explainer:

Hospitals, courts and a shopping centre (mall): Which other buildings are at risk of concrete collapse?

They're slowly doing assessments and it does seem really bad to me

[Governor Dinwiddie]

These days epoxy coated rebar is used in harsh conditions, damp locations, and near salt water.

[lepton]

Not just that, but when rebar rusts, it expands slightly, which can produce its own set of stresses on the concrete.