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Discussion Starter · #1 ·
I am new here and tried to post in the introductions. Not sure if this will go through either. I'm on an iPhone. I have already read the structural thread and have set up a meeting with an engineer. My question is:
I have framed a vaulted ceiling/roof over part of a new constructed house. Vaulted area is 18'x32'. Rafter span is 16'. Ridge beam span is 18'. Rafters are 2x10 yellow pine. Ridge beam is 2ply 16" lvl with 4 nails every 16". Collar ties will be directly bellow the ridge beam. 2x6 exterior walls through out. Question is rather or not the beam is adequate. Haven't took any braces down yet. Don't want too till I talk to engineer. Opinions are greatly appreciated
 

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How did you determine the size of the ridge? I have never used a microlam before on a ridge, unless the engineer spec'd it first. The rafter span is a little iffy as well for a 2x10.
 

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Discussion Starter · #3 ·
Well, as far as the ridge, I went with some advice from a more seasoned source. I was told a 2ply 12" lvl ridge "should" do the job. Should isn't enough for me so I ordered 16"ers. I have seen 2x10s rafters spanned further. Snow load is 15#. Rafters are 16" oc. There are also two dormers equally spaced in the front half to let more light in. Doubled 2x10's under each dormer wall. They aren't too big. If I knew how to post a pic with an iPhone I would. Ridge beam is prolly 5-6" taller than plumb cut of rafters. This was not supposed to be a part of this house and was changed last minute
 

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Discussion Starter · #4 ·
Ok Warren, you're making me nervous here lol. In hindsight scissor trusses may have been the way to go? Beam wasn't cheap. Wasn't light neither. There is no framing inspection required but I have built the house as if it were going to be inspected in the big city. It really makes me sick to my stomach to think that the beam is inadequate. The owner wants to keep the great room open, but if said beam is inadequate than I'm going to have to pull another rabbit out of the bag. The HO doesn't know I've made an appointment with an engineer yet. I'm doing that on my own and paying for it out of my pocket because I don't operate on uncertainty. I will never do anything without a sign off by an engineer ahead of time again. We all know the dangers presented by improperly framed roof systems of this nature
 

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Roof pitch? Not claiming to be an engineer but- I've seen garage headers
11-7/8" 16 ft wide carrying trusses many times. Going to the ridge instead different point load- you said doggy dormers so I'm guessing it's at least 8/12?

How low are the collar ties?
 

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Using the span charts for Microllam, a two ply 16" deep Microllam ridge beam looks adequate to support snow loads of 30 psf and dead loads of 15 psf. Your situation of an 18 ft span ridge beam and a 36 ft deep house is right out of the tables, no interpolation required.

Unless there is something odd about the dormers or something else in the structure, I wouldn't think your engineer should have an issue. He will probably ask you to add some nails. Should have at least three rows at 12" on centers......I would add enough to change your four rows to 8" on centers before he comes out.

Good thing you didn't listen to the "2-ply 12" should do it".
 

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Well this is just my opinion of what you are describing as the conditions you have, without any knowledge of the beam modulus of elasticity and so forth. I don't know for example if you are using LVls of 1.8 e or 1.9 e or what they are.
But, I THINK that it being as you describe, it will be O.K.

Do you not need plans, permits and engineering of any kind where you are?

Andy.
 

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Discussion Starter · #8 ·
@roofcheck: pitch is 7:12. Collar ties are directly bellow the 16" ridge. Collar ties aren't put in yet. Waiting to see if more beam is needed.
@rob: the house is 32' wide 2x10 rafters only spanning 16'. I thought more nails may be a better idea and will add 4rows in between the four I already have making it four rows every 8".
@andy: I'm not sure about the exact lvl (micro lam) specs and will be finding out before I meet with the engineer. There are codes where the job is but no framing codes. Doesn't make good sense to me at all. There was no plan/spec of any sort. Kind of a family thing. HO is clueless as far as design or construction methods and reasoning. If I knew how to post pics off an iPhone I would. The roofer told me he didn't want to use ridge vent, but I'm afraid he's in for a rude awakening. Thanks to all for you're opinions. I'm glad I've joined and hope to help others as well
 

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Discussion Starter · #9 ·
The backup plan if the engineer doesn't sign off would prolly be some decorated collar tie beams about 1/3 the way down from the ridge. Dread having to explain that one to the HO. he's dead set on keeping everything open. That or a decorated post at the end of his kitchen knee walls going to the ridge. Ill never build another house without a signed set of plans EVER again. The house was supposed to be a regular plane Jane house with flat ceilings.
 

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I wasn't trying to make you nervous. Like others have said, it seems like it is enough. I was just saying that in all my years, I have never guessed on a 2 ply microlam ridge beam. I am always under the scrutiny of an inspector though.
 

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Discussion Starter · #11 ·
Thanks warren. I'm uncertain about it only because of the nature of the situation. I thought I was way overkill. Sounds like I'm getting through by the skin of my teeth. I don't like that. A lot of u guys do some amazing work. Mind boggling. Makes my 15 years seem like a waste. This is my first time not being scrutinized by an inspector. First time (and last) time not having a set of plans signed by an engineer. Feels like Russian roulette. Don't particularly like the idea of potentionaly causing a disaster if u know what I mean.
 

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The backup plan if the engineer doesn't sign off would prolly be some decorated collar tie beams about 1/3 the way down from the ridge. Dread having to explain that one to the HO. he's dead set on keeping everything open. That or a decorated post at the end of his kitchen knee walls going to the ridge. Ill never build another house without a signed set of plans EVER again. The house was supposed to be a regular plane Jane house with flat ceilings.
Um, I think you do not need collar ties. If you can, install some coil strap on the ridge from rafter to rafter. About 24" long should do it, every other rafter to rafter 32" centers).
Just a suggestion. That way you could keep the open beam look.

On another note; why do you need ridge venting on a roof assembly like you describe?

Andy.
 

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ScipioAfricanus said:
Well this is just my opinion of what you are describing as the conditions you have, without any knowledge of the beam modulus of elasticity and so forth. I don't know for example if you are using LVls of 1.8 e or 1.9 e or what they are. But, I THINK that it being as you describe, it will be O.K. Do you not need plans, permits and engineering of any kind where you are? Andy.
Plans, engineering, permits? WTF is that?
 

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I was actually more concerned about the span of the rafters. If I had to guess on that one, I am sure I would have gone with 2x12 on that span. According to the guys in the know here, you are ok though.
 

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Discussion Starter · #15 ·
Isn't this not considerd a "hot roof"? Was planning on using epiphany spray foam insulation(or equivalent) to keep heating costs down. My understanding is that box vents would be inadequate ventilation. Condensation is also a concern for me. Especially with can lights. Maybe I've been mislead here. I'm a framer, not HVAC. What's you're opinion?
 

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Are the rafters installed on top of the beam or are they butted into the side? If the engineer says the beam is not up to snuff, and the rafters are on top, you could through bolt a pair of 12 or 14 inch ones on the side of the 16 inch double. If the rafters are butted in to the side of the 16 inch beam, you could add another beam below the 16 inch one. This way you don't have to rip too much apart and you could add the ceiling below the new beam to conceal it. If you have to add the beam below, be sure to shore up the rafters before you cut into the bearing points under the 16 inch beam. Hopefully the rafters are on top, much easier to bolt on the new plys.
 

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Discussion Starter · #17 ·
Thanks again warren. The more reassurance the less stress.
@californiadecks: All I can say is this is out in the country in kentucky. I've never built without plans/specs before. I think it's ridiculous. The only inspection is HVAC, electric, and plumbing. That's why I'm paying out of my pocket to get this ok'd by an engineer. I can't believe u don't have to pull permits to even START something like this. Hopefully this will all change. Too much fly by night in the mountains.
 

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the roofer told me he didn't want to use ridge vent, but I'm afraid he's in for a rude awakening
You would only use ridge vent if the roof assembly is a vented assembly which I would think this is not.

A "hot roof" it is, though that is a misnomer.

Yes the spray foam is a good idea to attain a good R value. Not familiar with the brand you mentioned but foam insulation is a science of its own.
I would think that if the foam you mentioned is a closed-cell type that that would be good but every situation is different and others will probably disagree with me.

Andy.
 

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Discussion Starter · #19 ·
Hey muskoka. Nope, the rafters but into ridge beam just like conventional roof framing. I figured another beam under the original as a possibility and maybe tying them together with rsv straps. Hopefully that doesn't become the resolve.
 

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I am not a framer, but have turned a flat ceiling into a vault, on a renovation.
Spray foam is your friend.
ventilation and condensation are a major concern.
Here where I am code requires R40 in a ceiling, or R28 in a vault.
I used 2x12 and wasn't confident of getting proper ventilation.
Spray foam does add rigidity to the roof structure but I'm not sure how much, engineerily speaking.
Keep us posted
 
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