Thanks for the feedback folks,
I don't mean to take away from the cruck discussion.

I can now see how this non-structural ridge made layout and assembly an easier task, but I'm still wondering:

These old time carpenters MUST have known that placing a post under these ridges would re-direct roof loads away from the plates, so why did they still not use them? As Tim suggested, was it because too large of a timber would be required for the ridge? But it seems to me, that issue was not often a limiting factor in the design of old frames. Or was it?

Tim, your earlier comment about the dropped tie as it relates to roof thrust raised yet another question. I always thought that dropping the tie from its ideal triangular arrangement resulted in an increase of rafter thrust at the plates (relative to how low it was placed) and created the need for tension joinery at tie/post, in effect doing the opposite as you suggested. Or did I misinterpret your explanation? Or am I simply a knucklehead and missing something here?

Gabel, Interesting stuff. Any particular reason why this type of ridge was not used once SR came on the scene?

In two of the later barns (much larger than the crucks shown previous) that I've had the pleasure of dismantling / moving there was evidence of a hay track having been installed. (granted, the hay track came along much later than many of the barns origination dates).

Posting down the center of the barn would have interfered with any operation out the gable ends. These barns had a queen post / purlin roof system - canted if I remember correctly, with posts dropping to the floor below the ties as needed. This kept things open through the upper floor / roof.


Size may not have mattered - here's a pic of me on an oak 'swing beam' on an Ohio barn that was restored into a residence. There were a pair of these and I think they easily hit 12x20 or more in the center (they were tapered from end to middle!). Size was probably easy to come by - but how to get that ridge up in the air might have been a determining factor in not wanting to use large pieces up high...

with square rule there is no time saved by having a framed in ridge.

Think of it this way - if each mortise or tenon is a joint, to join the peak of one pair of rafters requires two tenons and two mortises or four joints. If you delete the ridge and join the two opposite rafters to each other, you only have two joints whether you are doing half laps, tongue and forks or whatever. And since the structural advantage of the ridge is minimal, they just deleted it and I bet the guys that worked through the transition were glad to see it go.

Let's look at the framed ridge's benefit when scribing a little closer in order to understand why they would hew or buy additional timber and cut additional joinery and think of it as a cost saver.

The mortises in the ridge were all laid out and cut by measurement prior to laying up the roof plane. The same is true for the notches in the plate. The plate and ridge were set the correct distance apart, leveled and square to each other. Then the rafters could be tumbled. The process is described in detail in Jack Sobon's series on building his barn in Timber Framing (somewhere around issue 80).

Without the ridge, you still have to tumble the heel to the plate, but you also have to lay up each pair of commons to mark out the peak joint.

Mike, I'd like to know more about that swing beam. Looks a lot like a Dutch anchor with what looks like pent roof mortises. It looks like it is going into a corner post. Is this frame going back up fairly close to its original state, or is it made up from salvaged pieces? Do you have any other photos of that frame? Looks very interesting. Thanks.

My intentions were not that the size of the beam would be difficult to find but that it is a bugger to handle and in upper reaches of the frame, at that. All in all it's just me speculating. I would add to Mike's points of the king post getting in the way. When ever I construct a king post truss it is always in the way if you are using the attic space, barn, home or what ever, and any strut work makes it even more so.

Ron, I think you interpreted my words well. To clarify a bit more, most dropped ties are within a foot of the top plate, so it is still in the ball park. They had to create a joint there anyway, so to making it a through tenon with an extra peg and/or even a wedge on a half dovetail would be less work and material than the ridge and post set up. There is a lot of functioning dropped tie barns out there with common rafter, so it works.

Another approach would be the english tie but, from my perspective that does not handle thrust from common rafters well. The english tie gets your tie right where it is ideal and to top it off barks for a principal rafter and common purling roof system, changing how the roof system works in comparison to a common rafter system.

Ken, how were the rafters tied at their peaks if at all, other than the peg through the ridge? I used mortice and tenon to connect the rafter to the ridge. They were not laid on top as in the photo. I like that as an alternative, as long as I was not having to join the rafters at the peak. This example has me wondering if the cruck was to shrink than did the ridge drop too? It's like chess, 3 moves ahead and I stall out due to to many options, then you can go back over the game and follow the notations to see what happened.

Dave, I'll have to dig for some more pics. I helped for about a week with misc joinery and then raising. Location is near Columbus, Ohio. Pretty sure owner had 3/4 of an intact barn and we used pieces from a nearly identical barn for the remainder. I don't think they traveled far to get to his site.

The swing beams were in the center bay. In that photo the bent is being assembled for raising. Posts were gunstocked in the direction of the plate. Tie dropped on and then plate interlaced on top with a horizontal tenon coming in from the tie, then the whole assembly dropped 1 1/2" or so. If memory serves those pockets were from the loft floor.

Thanks Mike. A lot of the pieces in that photo are very much like the Dutch barn I'm working on. I'll have to get some photos up. I know we all like photos.

Thanks to all who contributed, I learned a lot, and it was much appreciated.

I talked to Jack a little about ridge beams today. He said it was builders choice pretty much. They don't indicate any particular period. Advantages and disadvantages are pretty much as described above. They do help straighten the lines of the ridge, but every joint in the beam is an extra joint. I'm working up an idea for a small shed we need here on the farm, and I want to incorporate a ridge beam in it. It might be somewhat cruckish, have to check the tree supply here.

I believe it was Eric Sloane who put a date range on frames with and without (non-structural)ridge beams. And I believe it was Jack that debunked that theory (among others).