Support for a beam in a sloped roof

[Rick D]

Hi all.
I’ve been giving some thought to a garage build in the spring and I want to go with a modern style sloped flat roof. Basically the front of the garage would be 2x6 framed and 16 feet in height and the back wall would be 12 feet in height.

The rafters would run from front to back for a total span of almost 28 feet (a 1 to 2 foot over hang on the front and back). I could go with engineered trusses but I’m leaning towards 2x12’s spaced at 16” on center. The rafters would each be 14 feet long in two rows with overlap on a perpendicular LVL beam in the middle where the rafters meet.

My question is about proper support for the LVL beam within the left and right side sloped walls. I’m thinking a 6x6 post or framing from multiple laminated 2X6’s together but what I’m not clear on is how that post is connected to support the LVL beam. Is it sufficient to cut the top of my 6X6 post to match the angle of the top plate (remember the walls are sloped) so it fits tight?

Or is it acceptable to cut through the top plate and create a pocket the height of my LVL so my 6x6 post makes flush contact with the beam? This definitely seems like the best way to go, but cutting through both top plates seems to raise concerns about its structural integrity.

I’m having trouble finding pics on how others have supported a LVL from side walls that are sloped.

Thank you.
-Rick

 

[Rusted Nut]

Support beams are usually set vertically, even in a rake (sloped) wall. If using dimensional lumber, cut the top of the beam to match the slope, but I would not recommend this with engineered lumber (LVL), just because I have no idea if this would severely degrade the strength. Cut angle blocks to sit on top of beam and under roof rafters.

 

[NimbleMotors]

Pics really help, the rafter beam is held up at the ends by a king stud and a jack stud, where the king stud goes to the top of the beam and the jack stud next to it is under the beam holding it up. So if I get what your asking about is the king stud? Should you angle the cut on it?
I don't think the king actually has to go all the way to the top, so just make it tad shorter. I think I used 4x4's for the king and jack studs on my addition with a LVL ridge beam.

I think Rusted Nut answered the next question, is how to get the rafters to sit on the support beam at the angle. 2/12 is a very small slope. My current workshop project has a 1/12 pitch flat roof and what my research found was trying to match them would not be any better than doing nothing. You could cut into the rafters to match where the meet the beam, it would take very little. So just like the birds mouth cuts at the ends. What I did on my 3/12 pitch roof addition was rip the angle into top wall 2x4 and actually the little piece ripped off the 2x4 was used on the ridge beam if I recall, as it has the same angle in it.

btw, when using a ridge board, the angle cut in the rafters to mate with the ridge board is a piece can be fit under the rafters on the wall to mate them to the top wall plate. I've done this on sheds I've built that have higher pitch roofs.

 

[billconner]

I'd do it like my sketch. Overlap rafters between walls, **** and splice at walls.

I don't know what your design snow load is not how wide the garage is, but the lvl could be pretty big. I'm just suggesting look at that sooner than later. For a 32' span, just supporting rafter ties and light storage loft (20 psf) I added an 8x8 post dead center, and a quad 2x12 beam.

 

[Rick D]

I'd do it like my sketch. Overlap rafters between walls, **** and splice at walls.

I don't know what your design snow load is not how wide the garage is, but the lvl could be pretty big. I'm just suggesting look at that sooner than later. For a 32' span, just supporting rafter ties and light storage loft (20 psf) I added an 8x8 post dead center, and a quad 2x12 beam.

Thanks for the sketch...this is what I meant when I said to create a pocket. As far as the support that's needed, I will bring my ideas to a local yard here and they plug in the dimensions and tell me the beam I need to use and where it will require supports and their size. Thanks so much folks!
-Rick

 

[Hank11]

You should price trusses for this. That might be easier, faster, and cheaper than you think.

 

[mike93lx]

You should price trusses for this. That might be easier, faster, and cheaper than you think.

This. Plus you should be able to clear span

 

[billconner]

I'd look at TJIs first for not loosing height. Easier to install solo than lvl or trusses.

But I came back to suggest a single top plates on the sides, since they can be unbroken to lvl.

 

[Innovate1]

Is there any reason other than aesthetics for the flat roof design? If that's what you want to do that's fine but a flat roof is hard to keep from leaking and trusses could easily span that. There's a reason trusses are common - cost and installation ease (which relates to installation cost). You could do a single direction slope and still do a truss. If you are set on the beams and nearly flat roof some support posts in the middle will keep the beam sizes reasonable. If you really want long spans maybe steel for the beams?

 

[NimbleMotors]

A flat roof is easier if you use corrugated roof panels. I did a chicken coop recently with plastic roof panels, and the peak was a pain.
I would have made it flat, but then you need longer rafters, whereas you can use almost half the length if you have a peaked roof.
The ranch had lots of old wood they wanted me to use.
It also works great for solar panels if the slope faces the south like my current project.

 

[Hank11]

OP described a sloped roof, not flat. 4’ of slope over about 28‘ distance.

 

[billconner]

Would trusses be less expensive than TJIs?

 

[billconner]

Ate at a micro brewery patio covered with this 40 x 40 low slope roof with trusses. I'd say the span is 40', and the trusses are around 3' deep at high end, 1' at low end. Bottom chord is level. 50 or 60 psf design snow load.

 

[volleyball]

Why the height limit? And what side is the high side of the shed roof?
I have two side by side decks that the supports are only 16' apart for the LVLs which is 3 2X10's. The pitch is only a couple of inches over entire span and I am in snow country. The walls are block and a few plastic shims were enough.
You can upscale the size with larger LVL's. I had a max height issue so the height underneath wasn't as much as I wanted. But it is solid for over a decade