Timber Framers Guild Forums General General Forum Questions peg joint?

I am housing a 6" x 6" side purlin into a 11" x 5" valley beam Is there a need to peg this joint and how would you do it, the other end of the purlin is built into a masonary wall.

Ooo...Nobody around but me to answer this one tonight?

OK, here's my 2 bits - but, as stated in Timber Engineering, I'm NOT an engineer...

I have only ever used lags (blasphemy!) to hold 6x6 purlins to valleys (only because that is what the client wanted...). A 1" drill hole with a 2" countersink at 1 1/2" depth, and then used plugs for the holes. But if your housing is at least 1" it may be just fine on it's own, and considering that your valley is 5", you may need to go with that. I have housed smaller purlins(4x4) and jack rafters (up to 5x8) without anything else, and that seemed to meet engineering requirements.

What I would like to find out from the pros out here is if pegging (as in actaul oak pegs) such a joint is common, or necessary.

*K

Also a non-engineering perspective: Any purlins I have joined were fully housed in addition to being tenoned to confer additional support and hide minor imperfections. The joinery is supplemented by lags, through bolts or knife plates. Can't beat the strength of ferrous connectors ... yeah ... more blasphemy ...

I have no idea what a lag is(this is not a term us welsh boys are familiar with) please describe.
I was going to use a tusk tenon joint as illustrated on page 60 of Tedd Bensons "Building the timber framed house" but as the purlin does not hit the valley beam/rafter at 90 degrees the joinery will be slightly different. How much will a joint like this weaken the valley beam/rafter, the purlin meets the rafter about half ways up its length/span. If this joint requires a peg would you peg down through the entire 11" of the valle beam?

I've also dove-tailed jack rafters into hips and valleys...Could try that.
*K

Now I know what a lag is, its what We would term a
"Coach screw". Would you drill and counterbore valley beam then screw through valley beam into end grain of purlin tenon to hold joint together

Rather than screws into end-grain, you might consider a flat metal tension strap concealed on the blind side, with it's lags or spikes thus holding in cross-grain. The strap can be let-in to be flush under the sheathing.

Pete

The purlin meets valley beam just below centre leaving 3" from top face and 2" from bottom face of valley beam/rafter so unable to use dovtail or strap shown any other ideas much appreciated, do you not think a lag would hold suffiently in end grain of purlin?

Greener, I found this Specification for Timber Frame Construction document at the Timber Frame Business Council website. There is material on pegging joints beginning on Page #9.