Approving Hip Rafter Sizes

[jar546]

Not to veer off center of topic, but, is there any objection to substituting engineered lumber for solid lumber for hip or valley rafters, or ridge boards . . . to increase dimension or avoid spilces? Also, what are acceptable methods to splice a hip or valley rafter?

To answer question 1, anytime we have someone specify an LVL or Glu-Lam, they must be accompanied by a spec sheet/cut sheet from the manufacturer for the specific application that they are used. An exception would be a ridge board since it is just for nailing.

Q2 I can answer as follows. If it is not prescriptive, which a splice is not, then we need a splice design from an RDP.

 

[mjesse]

I would have no problem accepting an LVL in place of a specified/approved dimensional lumber member. Work would be "exceeding" the minimum Code in my mind.

I would accept a piece of solid blocking/gusset for a ridge splice, and likely accept the same for a hip over 3/12 pitch.

As I've stated before, the valley rafter carries more load, so I would request and RDP spec for a splice for that.

mj

 

[MASSDRIVER]

At some point you start to exceed the capabilities of a 2x board to free span. I can't remember going over 28 feet before getting into a lam with a backing cut on top. Fortunately typ. residential has plenty of walls to hit a mid span support somewhere.

As a cutter I would rather use a nice strait long lvl so I have some consistant dimensions for layout.

Brent

 

[MASSDRIVER]

And to mjesse's comment on valleys, they seem to always have walls underneath to get strut on. It seems open roofs are more pleasing to see the underside of hips rather than valleys, but those usually carry a load from a ridge beam or other support.

Brent

 

[jar546]

Time to resurrect this important thread about hip roofs.