Frame design question for you experienced types

[Jim_Rogers]

Securing rafters at the ridge will reduce the thrust at the plate, but not eliminate it.
When you get your finial design done, then we can look at it and make more comments.

You should consider getting a timber framing engineer involved to make sure you have all your eye's dotted and tee's crossed.

Just a suggestion.
I know several who can look at your sketchup drawing when you have it done.

I'm not the best on thrust, so that's why I hire them.

Jim Rogers

[Thehardway]

Randy,

Did a google search on the Patagonia train station and the pictures I pulled up were not a hip style roof.  Might be some confusion on my part.  Here is a picture of the Chatham Depot which is about 15 mi. from my new place.  A lot of history here.  The old #97 passed this building on the day of its famous and fateful wreck.  I think it is a great representation of a hip roofed building with large overhanging eaves.  Might be a good reference for you. It is currently undergoing restoration to become a veterans museum.  I am curious myself to see how the hips were framed on this.   

 

There are several more nearby here that use this same general style.

I like that dragon and cross joint but I'm not sure how it will work with the eaves you are looking to add.  I think the large brackets might be a good idea for you  to add the eaves on. I echo Jim's advice to get an engineers opinion after you have all your fun designing and drawing.  When dealing with spans, there is a limitation to the over engineering approach as the larger your timbers get, the heavier they are and they must bear their own weight as well as that of the structure, hence the idea of the truss sprang forth.  You can't always be safe just by adding girth to your beams and timbers. In some cases it may actually be worse to up size.  I'm sure you have already considered this but sometimes in the excitement of drawing big massive frames we focus too much on the dead loads, live loads, snow loads, wind loads etc. and forget the weight of the structural members themselves.  Being that this will be more or less two independent structures (TF and adobe) you  need to make sure settleing issues are addressed properly. 

[moorerp]

hey Hardway, thanks for the input and the image.  That train station's roof is pretty much a carbon copy of the design I have in mind, even down to the slight flare of the overhang.  If you run down any info on how it was framed, I'd be much obliged to hear what you found (or see what you photographed, especially).

cheers,
randy

Randy,

Did a google search on the Patagonia train station and the pictures I pulled up were not a hip style roof.  Might be some confusion on my part.  Here is a picture of the Chatham Depot which is about 15 mi. from my new place.  A lot of history here.  The old #97 passed this building on the day of its famous and fateful wreck.  I think it is a great representation of a hip roofed building with large overhanging eaves.  Might be a good reference for you. It is currently undergoing restoration to become a veterans museum.  I am curious myself to see how the hips were framed on this.   

 

[thurlow]

I pretty much don't understand hardly anything atall of what all y'all are saying and the terms being used;  I suppose that's cause I'm a barely literate, retired dirt farmer. Of course it could be 'cause I live here and y'all live 'there'.  Howsomever, I have built numerous buildings which are still standing and will continue to do so absent a tornado (the old folks usta call 'em cyclones).  The sketch of your roof looks very similar to the roof on my pavilion (24 x 30 or could be 32..........I disremember).  If I recall correctly it has 2 x 6 rafters on 24 inch centers;  that may not be an option for you..............



 

[moorerp]

Heck, I just barely understand most of the terms used on this site, and have no idea about the rest.  I've built part of exactly 1 timber framed structure, and most of what I know comes from that project, plus a lot of reading stuff on the internet. 

Like moderator Jim says, though, if you're gonna discuss this stuff (or beg for help in my case), everybody needs to be on the same page language-wise, so I'm suckin' it up and learning the lingo.  It does make things easier, I have to admit.

That's  a nice looking pavilion, and it's pretty close to what I have in mind.  I'm gonna be using a lot bigger timbers, though.

cheers,
randy

[Thehardway]

Randy,

I'm jammed for time right now to get my house done and moved in as we close on April 30.  If it wasn't for that I would track the info down on the train station right away for you.  You might want to try calling the folks there and see if they could point you to some documents or photos of the reconstruct until I can get free to find you some info.

By the way, what you are calling a "flare" has a technical timberframe name.  It is called a sprocket.  A sprocket is a small wedge shaped piece of wood attached to the rafter to flatten the pitch and extend the roof at the eave.

This was done for more than just looks or a large overhang.  The purpose was three-fold.

1. It reduced the velocity of rain run-off before it came off the roof into the gutter (in some cases gutters were actually concealed and built into in the roof)
2. It served as a means of breaking up sheet ice that formed on the roof so that it would not slide off the roof in one big piece and kill someone below.
3. it kept water off the side of the building.

Another term associated with this type of roof is a rafter "tail". rafter tails were often used to form a sprocketed roof and extend overhangs.  They were frequently cut in a decorative design at the end and left exposed or in other cases they were used to support and attach the cornice.

Although sprockets and tails are different in cut, placement, and attachment, either can be used to give the same look to a building.


For a more comprehensive understanding of timberframing terminology the TF Guild website has a number of articles you can download with pictures and illustrations to help understand what they mean.  Interestingly though, both the terms here are not in their glossary but are found in the article on joinery.