When purlins meet on the principal rafter, the timber framer needs to find a suitable joint that strikes the right balance – take too much out of either structural member and the roof might fail. No pressure there then….
The lightning scarf can be a good choice if the purlins are trenced down onto the principal rafters. It’s a classic scarf – a means of joining one timber to another along their length, and of course it’s also an opportunity not to be missed to show off with a bit of snazzy carpentry.
Here are a shoal (collective term?) of lightning scarfed purlins waiting for assembly in the workshop, and one joint temporarily pinned with podgers.
If you're considering an oak framed building (or larch, or douglas fir), let's talk. We'll gladly put together an outline quote (completely free, with no strings attached). And we need very little information from you to do so.
Equally, we're always here, at the end of the phone, to talk through your ideas.