Broken purlin hangar

A relative lives in a late 1920's built semi detached house with the ridge running from side to side and a hipped roof at each end.

The hip rafters are supported by one purlin which itself is supported by a vertical strut (hanger) that rests on an internal load bearing wall.

The hangar has snapped, almost like a matchstick, without completely separating into two parts. The ridge (and tiles on it), when viewed from outside, is not visibly sagging or deflected, nor is the purlin that rests on the hanger, or the hip rafters themselves.

A few years ago the neighbour in the other semi had major roof conversion works as part of an extension which included a dormer on their hip (and front) roof. Shortly after their extension was completed, that dormer was seriously damaged in strong winds. (This was in East Anglia).

Can anyone suggest possible causes of the damaged hanger, and in particular is it possible for works on the other semi's roof could be a cause or a contributory factor?

Finally, I cannot say with certainty when the damage occurred because the loft is not used or visited, but the break in the wood seems to be clean and relatively fresh compared to the remaining timbers which are covered in the fine dust and debris that has settled because of the property's unfelted roof.

Cheers Blup

Roofs flex, and these struts (and purlins too), commonly split. It's normally a gradual thing over many years, and a split can still look fresh after decades

I can't imagine how loading from a neighbouring roof could affect a strut.

Woody

That's really appreciated, thanks.

My nephew's a carpenter and he can probably replace the strut, presumably the purlin would need some temporary support whilst this is being done?

Cheers

Blup

It might be easier to put a piece of timber either side of the strut, drill two or three holes through, and use bolts or threaded rod to pull the strut back together as they are tightened. This can save messing about trying to prop the purlin. But if the purlin can be propped easily, then yes do that and put a new strut back in - 4x4 or two 4x2's screwed together