Purlin joint separated

[Horrible Username]

Hi all, first time posting, I'm hoping some of you kind folks might be able to help.

A purlin in the roof of our new house was flagged up by the survey. One of the lap joints has separated, leaving something like a 1" gap (pictures give a good idea of the extent of the problem). The surveyor has suggested a structural engineer might be worth consulting on how to repair or reinforce the joint. There's no sign of the roof sagging, and it doesn't appear to be causing a problem for the moment.

We chatted with a friend with plenty of experience who says this might require removal of tiles, supporting the purlin during repair etc etc, which sounds expensive and invasive compared to another roofer who came around and said the joint could be simply clamped back together and repaired with a suitable plate or length of timber attached to the side.

Another thread on this site (https://www.diynot.com/diy/threads/spreading-lap-joint.249085) describes what seems to be a similar problem, with the general consensus being to not force the joint back into position but rather reinforce it to prevent further movement.

I wonder if anyone has any further suggestions?

I've included a general photo of the rest of the roof (including obligatory copy of 'Escape from Colditz').

 

[robinbanks]

Dare say the recommendation not to force it back together comes from it having taken years to settle to where it is now. To shove it back together over a few seconds with some aggressive mechanical device will probably just snap the ends. If you want it back together, mimic the process that got it to where it is now except in the opposite direction - jack or bolt it and tighten somewhat, then leave it a month or two, then jack/tighten some more. Eventually, it'll be back where you want it

Surprised that you don't see any roof unevenness though; the rafters look to be quite misaligned. Perhaps the battens pulled out of the rafters rather than following them down

 

[Harry Bloomfield]

I agree with Robin, above. A G-clamp (or a pair H and V) tightened a little at a time, until it is all aligned and resettled - then sister it with a length of timber, firmly bolted (threaded rod) across the joint, bolted in four places, with large washers.

 

[blup]

I would take advice from an SE, for a couple of hundred pounds it will give peace of mind. As a temporary measure you could fill the gap with some hardwood and prop the join bit from underneath.

Blup

 

[Harry Bloomfield]

I would take advice from an SE, for a couple of hundred pounds it will give peace of mind. As a temporary measure you could fill the gap with some hardwood and prop the join bit from underneath.

It obviously not under much strain, or a crucial bit of timber - or a more robust joint would have been specified, during the build.

 

[blup]

It obviously not under much strain, or a crucial bit of timber - or a more robust joint would have been specified, during the build.

I suppose the ridge board is taking some of the load but was it designed to do this.

Blup

 

[Horrible Username]

Thanks so much for all your replies. I'm inclined to check with a structural engineer, especially as given the slightly unusual design of the house there's some possibility the purlin extends through the party wall into the neighbour's loft conversion. If this is the case, I suspect we'll simply try and maintain the current position by fixing some plates or something on, rather than forcing the joint back into alignment. We shall see.

I've attached a picture of the roof structure from the outside, so you can see what I mean about the purlin extending through to the neighbour's side. The party wall aligns with the change in tiles. The offending joint is probably around where the tip of the aerial points to.

Thanks again! I'll update if and when I have any more information.