fix a concrete lintel

thingy to it?

Waste of time trying to fix it. Either remove, shutter up, and cast one in situ, or slide a replacement in and make the brickwork good above.

AWEM

I'll second that about the repair, wouldn't cast in situ, but you need to use strongboys and take out at least two courses of bricks above the lintel or replace with catnic. Concrete plank lintels depend on the bond to the courses above to be under sideways compression load while they take the tensile stress.

AJH AJH

Whatever you do the lintel itself isnt repairable, as it'll continue to rust, and break open again. If for whatever reason you dont want to replace it, just face it with somehing that doesnt mind slight movement. I'm assuming it onyl covers a normal front door in a brick wall, and thus doesnt need replacing for structural reasons (hypothetically if you sawed it in half it would still work, it would be cantilevered).

NT

This assumption depends on knowing which way the ceiling joists and rafters carry the roof.

AJH

It has nothing to do with the set up of the ceilings or joists. You could remove those, in principle, and the setup would still work. On a typical door you've got about 2.5 feet of span, and 6" overlap at each end of the lintel. Saw it in half and you get 1.25' holding up half a small triangle of bricks above the door, and 0.5' with a whole storey of bricks atop it. Obviously its not as per original design, but it certainly works. Some lintels are a big deal, some are really a lot less so.

NT