Failed/blown concrete lintels - replace or repair?

[Kocher]

Two inner concrete lintels(100x~250) supporting 1/2 of external 30s solid walls, one supports a 1.8m window opening in 1st floor (carrying 3 courses and roof) and the other a 2m window opening in ground floor (supporting 10 courses and then an exact size window opening in 1st floor), are blown due to corroded reinforcing bars. The ground floor lintel’s bars are popped out on one side and held to the concrete with plasterboard adhesive! And there is a vertical crack right at the start of one of the bearings (all these are localised to one end of the lintel) :/ to make it worse the joist ends are sitting right one this lintel ... The 1st floor lintel bar is so bad that it crumbles off when you touch it and blown the concrete at the bottom.

I have no idea how they are standing, maybe the widndow frames are supporting them? I doubt they are that strong but not deflected .... yet.

It will be a hell of job replacing them due to their spans and joists and roof bearing on them. So how bad is it leaving them taking into account they been like that for god knows how long? And if they get replaced, how to prevent such a defect reoccurrences? Also how come the outside lintels look perfect from outside?

P.s front 0.9m door outer lintel is the same and two other 0.9m and 0.5 window opening inner lintels are diagonally cracked by the one of their bearing, but I’m not so fussed about them due to their small spans ... or I should be?

Any chance insurance can cover these? (1st time owner)

 

[^woody^]

Many concrete linterls have cracks in them and stay up OK

 

[Kocher]

I’m thinking the same, but a vertical crack right before the bearing worries me a lot. I have attached some pics for more info. I did brush off some of the corroded bar and it seems like not completely corroded so a patch repair could do it.

FYI that plasterboard adhesive is something very strong!

 

[^woody^]

Err, that's a bit more than a crack.

Looks like the lintel is made from flyash concrete, and was getting wet which accelerated the reaction with the steel.

Normal (or even abnormal) wear and tear , not normally an insurance risk.

If these are internal only lintels, then not really a difficult job. But if there is another issue - water egress to the lintel, then that will need sorting out, or may be dealt with when these are changed via a DPC tray.

 

[Kocher]

I have noticed signs of the old cast iron gutter joints leaking (due to be replaced) above each ends of the lintel, this could be a reason for the 1st floor lintel but no idea what’s causing the ground floor lintel reinforcement corrosion.

Also if it’s gutter in the case of 1st floor, how come the outer liner not affected .... will find out when I get to remove the lintels I guess.