Had anybody come across this ? http://www.fairbankshouse.org/barn_frame.pdf

The most interesting aspect of it for me is that the roof is Common Purlin. The barn had stood in Essex County Mass, and I've been informally trying to learn how common that roof system was there on that bank of the Merrimack.

Took in a bunch of the house museums in neighboring Ipswich last Autumn (though I believe the season is over now) which boasts of holding more 17th ca homes than any other town in America, and over fifty First Period homes. The only one I was able to talk my way into the attic of, the Whipple House, had Common Purlins in its original wing, but common rafters in a mirror image wing built just a few years later. I almost broke the no flash photography rule up there, the docent had no interest in climbing around in a grimy attic with a crazy person and stayed downstairs with Molly.

Will, did you take pictures?

Why is it they do not want photos take of the interior of these buildings. I have come across this locally, the photo taking part.

Tim

I have some shots of the outside of the buildings, but no, none of that attic, and had I taken any, I guess I would be reluctant to post them here, where I lack any real anonymity...

More about the Whipple House here - http://www.ipswichmuseum.org/whipple.php

I do have some of visible framing in the NH Royal Governor's Mansion which we visited in the same stretch of time, and which is maybe only twenty miles north of Ipswich http://en.wikipedia.org/wiki/Wentworth-Coolidge_Mansion I've a friend who is a docent there, and he wanted help in answering what are common questions about the framing there.

I'll see what I can find when I visit my desktop over the holiday and see if there is anything worth sharing.

Oh forgot,

Always guessed the no flash thing was about undue UV, and how light and time fade everything, but that's a guess.

Hi Will,

Interesting find. Nice and old, even dendro-dated.

It does seem like there ain't much rhyme or reason to the whole purlin vs common rafter thing. This befuddled me greatly in the begining of my poking around here in Maine. Always wondered if it was a cultural choice or something else.

But I'll hazard a guess that common rafters were employed over a major-rafter / purlin system at times simply because they're easier to construct: no joinery to really contend with... I don't know...or maybe sawn stock was cheap and easy in a given cicumstance, vs hewing major rafters ?? What are your thoughts?

At any rate, the photos of that old barn frame look almost like a connected girt type...almost. The plate is quite small, more like its neighboring purlin stock, perhaps used more like a nailer for the wall/roof boards. But there does seem to be a jowled post. So far I've yet to see a CG w/ jowled posts.

Speaking of dendro-dating, anyone know where one can get this done (do you ship a sample, etc)? Is it expensive?

Jack Sobon told me that he thinks purlin roofs were built when a board roof was to be used and rafters were used with shingles. Makes sense to me.

Looking at your example, Will, perhaps when the extension was built the owners had more money to build with and could choose the pricier shingle roof, hence the common rafters. Perhaps at the same time they even upgraded the original house to shingles, replacing the worn out (or perhaps just "low class") board roof.

I guess I don't get that, while yes, it would be more expensive to shingle a purlin than a rafter roof because you would have to first board over the purlins and then apply skip for the shingles, it would require no fewer layers to do board roofing over purlins - Though you can do board roofing over common rafters with no sheathing whatever, doesn't get any cheaper than that.

And it doesn't explain the regional dominance Common Purlins hold in much of Northern New England. Just across the river from where that 1715 barn stood you're in common purlin land, which is why I have a curiousity for how common they were on the south bank.

And as I have said in other threads, they are (and were hereabouts for a good 200 yrs) a perfect marriage with ETJ's - No load path whatever for thrust to reach the Plates.

I don't think you can get any cheaper than a single layer of boards nailed to the purlins. Not a great roof, but it gets you a few years in the dry. I don't know if they were shiplap or feather-edged or exactly how they kept the wet out.

I guess the shingles were pricey by comparison. There is certainly more labor in the install and more work in the making of them.

I'm not an expert on this, but it is interesting.

This was one of the most interesting buildings I think I have ever been a part of dismantling. What he web site doesn't show is that it was a "ground bound" building in that it had no sills, just a HUGE lower girt that was half lapped into the posts and pegged. The tie beams all were tapered as were the plates. It looked as if they simply squared up the trees and used them as is. If I remember right, one of them was very curved. Some of the purlins were straight, some curved. All of them were hewn flat on one side. Also, if memory serves me right, most of the frame was oak and chestnut. Whatever the species, it was really heavy.
Back to the original question. . .I do see a lot of common purlin roofs on barns and house from that era in that geographic reigon. Mostly on buildings before the 1760's. Also, in many cases, the purlins run the length of the building uninterupted.

Dan:
Welcome to the Forum.....