Tim, yes, eastern maine is a bit of an anomaly. And not FrenchCanadian. I have read that purlin frames are typically not found in the northern part of our state... Roughly above Bangor. Can you confirm?
Of the 4 "CG" frames I've seen here in southern Maine. One clearly shows pegged purlins. The others aren't as obvious. One that was restored had new purlins put in and they were spiked on. I'd have to go back and check on the others. And I will some day in the near future...
By the way, dovetailing the purlins into the rafters would be a neat method.
