All,
Working on a barn design and I want to have a Gambrel roof. I have spent a lot of time looking for some details on the typical joints at the rafters and have not found anything (internet, forum, books). With it being such a typical barn style I am a little surprised not to find the info. If someone could provide me a pointer it would be much appreciated.

Osage

Hi Osage,

Enter "Gambrel" in the Search box and be prepared to be overwhelmed.

Follow the various links to find lots of book references.

Regards

Ken Hume

Are there no Gambrel roof barns on that side of the puddle that you could go and look at Ken?

Ok never mind. I'm just learnin to read. duh.

you come up with and ideas Thane? lets see em.

mo,
Thus far I have not designed a Gambrel roof. All that I have seen have used what I call a tipped Queen post and purlin. The lower common rafter is notched into the plate with the top nailed to the purlin. The upper rafters are notched into the purlin and are simply nailed to one another at the peak. The tipped Queen post has a long brace which extends down to the Tie Beam. This setup puts very little thrust onto the Tie Beam.
Now, if I was to design a barn for myself I would straighten the Queen post which makes it a "H on H frame. I would also add a ridge beam which eliminates the thrust from the upper rafters. I don't recall but I read somewhere a few years back that whenever possible, the frame should be designed so that there is little or no tension at any joint. I agreed with this %99.
In this design, it should not be nessesary to notch either the upper or lower plates. Just birds-mouth rafters with large screws.
At least that is what I would start with. Normally as I progress with designing, I see things and make changes.

Please, feel free to add your professional opinions.

Osage,
We've build a few Gambrels a few different ways. Below are a few pictures of one we are working on now. This one has a conventional rafter roofing system. We've done the same frame with a principal rafter/purlin system. Hope this helps.

Pete

MTF, a thing of beauty. Thanks for posting.

I will soon be building a shop very similar to the pictures posted by MTF. I plan to use a plate, purlin system with common rafters spiked on. I wish I could add more craftmanship to the rafters really but this seems to be the most practical way and I know this is an authentic way to attatch rafters. My shop is still in the design phases, but I have compiled a timber list and have started cutting beams. I have gotten a little side tracked lately because I bought an old saw mill to hasten the process and it requires a little work.