I've noticed on a number of jobs over recent years that when frames have been replaced by others, esp. the old double-hung box frames, the old in-situ horns are merely cut off to allow the main frame to slide out.
These wooden horns, mostly wet-rot damaged, are then left in place in the masonry reveals. In time they can develop dry-rot, and damage from dry-rot strands creeping thro plaster and woodwork can be located some metres away.
The thing is to remove the horns and or any fixed timber pads from the masonry and if rot of any kind is present to treat with anti-fungal paste or liquid.
An example: when a householder had PVC frames installed in a bathroom for a few hundred pounds 5 years later a bath room demo was required to cut out and treat the true dry rot damage in walls, ceiling and floor at a cost of some thousands of pounds, all traced back to the left in-situ horns. It's not only not fair but a dishonest and deadly practice.
These wooden horns, mostly wet-rot damaged, are then left in place in the masonry reveals. In time they can develop dry-rot, and damage from dry-rot strands creeping thro plaster and woodwork can be located some metres away.
The thing is to remove the horns and or any fixed timber pads from the masonry and if rot of any kind is present to treat with anti-fungal paste or liquid.
An example: when a householder had PVC frames installed in a bathroom for a few hundred pounds 5 years later a bath room demo was required to cut out and treat the true dry rot damage in walls, ceiling and floor at a cost of some thousands of pounds, all traced back to the left in-situ horns. It's not only not fair but a dishonest and deadly practice.