Thread: ridge beam butt joint ?

A stepped scarf would be better, with mechanical fixings like bolts through it, or a steel plate either side with bolts through it. That’s a big beam, and a big span. Good luck.

Did you mean 32mm thick? I can’t imagine the need for a 320mm thick beam. In any event, I imagine a couple of large plates with through bolts, but you would get the best, safest answer from an engineer. And just out of curiosity, were you not able to get the beam made full length?

I’m with Greg: speak to an engineer. Get that wrong, and you are talking death or, best case, ‘just’ a complete roof collapse destroying the property when no-one’s home... I hate having to pay extra, but every once in awhile, it’s a necessity -this sounds like one of those cases. Riverbuilder’s solution is probably right, but get a qualified guy to confirm the specifics...

(I’d also suggest that your supplied details prove the point: the room width and height of ridge are irrelevant - all that matters is the beam rigidity, span, and the load on the beam- it’s a childish calculation for an engineer, but not up for guess work)

Originally Posted by Greg Q

Did you mean 32mm thick? I can’t imagine the need for a 320mm thick beam.

I think you missed the bit where he said it's an 8.5m span. 32mm would be a toothpick over that distance.

Also, +1 for getting an engineer involved. Getting something like this wrong could kill someone.

Is it a ridge or a beam ?
One is supported by the rafters and the other is supporting the rafters.

Also, what is the roof cladding and ceiling cladding and also what are the walls constructed of? Are there any collar ties or tie beam across the walls. What is the roof pitch? What method is used at the apex to support the rafters, are they butted into the beam like a traditional ridge or are they birds mouthed over the ridge and plumb cut abutted or lapped.
I'm surprised that the issue wasn't sorted during the design / engineering phase !!!
Regardless of any answers to the above, you have a responsibility to get an structural engineer to specify the method and sign off the certification when completed.

There's no way we, Australians, can answer this for you in any meaningful way.

If this beam is supporting rafters and not just a ridge beam then I calculate you would need 2x 600x63mm LVL to span 8.5m. That's assuming tile roof and designing for tropical Queensland conditions. I assumed these would be the closest weather and wind conditions for Greece. I have also made assumptions for roof pitch as this affects the roof load width required for beam design.

We also have no idea on the species of the timber, the type of glulam construction, how many laminations you have... list goes on.

The short answer is that a timber designer/specifier or engineer will need to make an assessment on this. As soon as you add a join the beam is no longer a single member. If you joined them with steel brackets and M12 or 16 bolts through the beam that that would probably be OK but the joint location would also be a factor.

TLDR.. need an engineer. No way around it.

Start thinking a support post or wall at the joint. If the beams were laminated they could have been any length required so I assume access was an issue. Fish plating a beam of such proportion over such a span will require some pretty series design consideration and will be very dependant on the material used to construct the beams in the first place. Cast an eye along the edge of the beams, they may have been constructed with a creep curve. If so, this will wreak havoc on a scarf joint once loaded, unless the scarf is made "live". In other words, the joint is formed to close once the load is applied. At this stage the beams still require verticle support until fish plates are installed. To be honest, IMHO they will still require verticle support.
Good luck.

What about a king post truss with rods coming back to mid span of each half ? Done one of these before it was pretty good.