How would you make this timber joint??

On Sat, 24 Apr 2004 21:19:51 -0400, Terry King <[email protected]>
wrote:

>
>> add an fha strap from the rafter over the top plate
>> and tie it in to the wall framing.
>What's an FHA strap? Some government required anti-hurricane
>roof-liftoff device, maybe??

yep. a length of sheet metal a couple of inches wide by various
lengths with holes for nails. bendable enough to frinstance hook one
end over the top of a rafter, get a few nails there, run it down the
face of said rafter (more nails) give it a twist to lay flat on the
face of the top plate (more nails) another twist to lay flat against a
stud (more nails)..... in situations where tension loads are a factor
they can add a lot to a connection.




> Are these standard items, or might steel
>strapping be OK??

there are lots of versions, fha (federal housing authority) required
and others. lots of use-specific ones and lots of general purpose ones
too. a place to look into it would be:
http://www.strongtie.com/products/woodwood.html?source=hpmain

if you mean steel strapping like what pallets are bound with, I
wouldn't. too light, no nail holes and no inspector will pass it.


>
>The max uplift in this design is only about 200 pounds as I recall,
>unless you use South Florida data...
>
>Thanks for the ideas....

> add an fha strap from the rafter over the top plate
> and tie it in to the wall framing.
What's an FHA strap? Some government required anti-hurricane
roof-liftoff device, maybe?? Are these standard items, or might steel
strapping be OK??

The max uplift in this design is only about 200 pounds as I recall,
unless you use South Florida data...

Thanks for the ideas....

--
Regards, Terry King ...In The Woods In Vermont
[email protected]
Capturing Live Music in Sound and Images
http://www.terryking.us

Terry King <[email protected]> wrote in
news:[email protected]:

> I need to decide how to join the gambrel roof rafters on the barn I'm
> building to the top plates running along the top of the side walls.
>
> The top plates are 8" by 8" beams. The rafters are 2" by 8". (These
> are all actual sizes, native lumber). The angle they meet at is 55
> degrees.
>
> I'd like to do more than the small 'birds mouth' that occurs the way
> the pieces meet, by some amount of cut-in to the plates. But what's
> the best compromise of attaching strength VS minimizing the material
> removed from the plates? What's a strong geometry here? I can rout
> some shaped cut-in in the plates, but I'd sure like to do that on the
> ground, soon now.
>
> I will have 1" thick purlins on the outer surface, and so I can set
> the rafters in 1" more than shown to get more material at the inner
> end of the joint.
>
> The max. bad wet snow load is 1500 pounds vertical, and 1000 pounds
> outward. I plan to use a 1" wooden peg or a large lag screw in each
> joint; this is not necessarily traditional timber frame construction
> totally...
>
> Take a look at:
> www.terryking.us/public/gambrel3.jpg or
> www.terryking.us/public/gambrel2.jpg
> for what this looks like.
>
> Suggestions, pointers, comments appreciated! I have some books but I
> haven't found this joint discussed.
>

See if you can find something on Japanese joinery. I've got a vague
recollection of something similar in a book on Japanese construction.

On Sat, 24 Apr 2004 09:50:35 -0400, Terry King <[email protected]>
wrote:

>I need to decide how to join the gambrel roof rafters on the barn I'm
>building to the top plates running along the top of the side walls.
>
>The top plates are 8" by 8" beams. The rafters are 2" by 8". (These are
>all actual sizes, native lumber). The angle they meet at is 55 degrees.
>
>I'd like to do more than the small 'birds mouth' that occurs the way the
>pieces meet, by some amount of cut-in to the plates. But what's the best
>compromise of attaching strength VS minimizing the material removed from
>the plates? What's a strong geometry here? I can rout some shaped cut-in
>in the plates, but I'd sure like to do that on the ground, soon now.
>
>I will have 1" thick purlins on the outer surface, and so I can set the
>rafters in 1" more than shown to get more material at the inner end of
>the joint.
>
>The max. bad wet snow load is 1500 pounds vertical, and 1000 pounds
>outward. I plan to use a 1" wooden peg or a large lag screw in each
>joint; this is not necessarily traditional timber frame construction
>totally...
>
>Take a look at:
>www.terryking.us/public/gambrel3.jpg or
>www.terryking.us/public/gambrel2.jpg
>for what this looks like.
>
>Suggestions, pointers, comments appreciated! I have some books but I
>haven't found this joint discussed.



first, my framing experience is almost entirely with stick framing, so
I may not be following what you're doing entirely, nor may I have good
solutions for you. but hey, it's usenet....

you show neither ridge nor collar ties in your drawing. I hope you're
not building it that way...

you could mortise the tails in, but make sure you leave plenty of
material at the outside of the mortise. make sure that any cuts you do
make seat in towards the inside of the building. it might be
necessary to cut a shoulder on the tennon to leave enough wood around
the mortise

if you move the rafters in to account for the purlins the horizontal
amount will be more than the 1" thickness of the purlins. I'd bet it
will give you plenty of strength in the birdsmouth. if you're still
worried about it, add an fha strap from the rafter over the top plate
and tie it in to the wall framing.