Joining new slates with existing slates

[rreanor]

I have a small lean to roof which I'm removing the corrugated covering from. The roof is shared with next door who have slates. My side probably also had slates as they currently underlap my corrugated cover by about a foot or so. The slates my side must have slipped at some point and someone added the corrugated covering.

I've got new slates coming next week which are the same size as next door. Will this need some sort of jointing gutter, or can I just lay the new slates in continuation with the existing ones? See pic.

 

[DAZB]

You would ideally just continue the slates in line with the neighbours assuming the lats are there and if not it is easy enough to re-lat it through your side keeping the spacings between lats the same.

 

[Mrs Ten Names]

If there's a membrane in place, it should overlap by 200mm minimum.