What kind of specialist fixes party wall gaps?

[CambyMum]

A surveyor found gaps in party wall in the attic of the house we want to buy, and he strongly recommends we hire someone to stop up / fireproof the gaps.

What kind of trades person fixes party wall gaps?

a builder

but it depends how big they are. If it's just shoddy old bricklaying then they can be filled with mortar using a ponting gun. The co-operation of the neighbour would be useful to do both sides neatly.

But perhaps there has been movement, especially if there have been loft conversions, roof alterations, rooms knocked through, or if an old (light) slate roof has been taken off and a new (heavy) concrete tiles laid on the thin weak timbers. This might be a construction issue.

Pink expanding firefoam is also useful for blocking small gaps, e.g. where timbers are built into walls. Again the neighbours co-operation is preferred or it will be messy.