Half way up, probably between ground floor ceiling and upstairs floorboards (if that makes sense)how high up the house are they, and what's on the other side of the wall?
No, not on the same wall, unfortunately. That area has dried up and the sill beaded with silicone. No issues since.are these marks near the damp patch on the wall you mentioned earlier?
Buy a camera. Drill hole through and look.
Cheap enough.
Or find builder with camera to look
Ferrous ties have not been used for decadesBet it's rust from wall ties. Get a studfinder up there.
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