Large Vaulted Roof Sliding Off Supports 5

[cap4000]

I made an inspection of a residence with a newly constructed vaulted roof. The architect has been fired so I am trying to fix the roof which may have to demolished. Essentially its 16 feet high down to 9 feet, 50 long and 30 feet wide. The roof is sliding off its supports at this point and the nails are withdrawing from the ridge beam. I have an idea with a reinforced concrete structure at the low end but I want to be held harmless first. Any tips will be greatly appreciated.

 

[msquared48]

A sketch would be helpful. Knowing the structure of some Architects, it is probably something simple structurally that was missed.

I would look to:

1. The lack of an over-the-top tension tie at the ridge beam; or
2. The lack of a notch in the rafters for flat bearing at the outside walls; or
3. Collar-tie action that was not designed for with collar ties being omitted.

Or something else.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[cap4000]

Thanks for the reply. None of those 3 items are in the design.

 

[ToadJones]

HAHA
Well, don't go inside the structure again!
I'm sure the archy loved the way it looked right before it started to collapse.

 

[msquared48]

Note that if a large ridge beam is present, collar ties are usually not required. However, that does not mean that the ridge beam was properly sized. Too much deflection in the ridge beam can cause lateral spreading of the exterior walls too, particularly at the rafter spans you are talking about.

What is the pitch of the roof?
What is the size and type of the rafters?

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[ishvaaag]

You can even jack to position the roof if of sound construction and ensuring no dislodgement occurs in the process. Then you can reinforce the base for the original attempted position. To this effect you may add inner rigidizying bracing the same than inner connections in bones of birds, and weighted guides in the sides of the eaves.

On the other hand if something, and that is natural, you have indemnity of what others have made prior to your engagement to salvage the work. You can get such statement from the owner, maybe. But I doubt anywhere in the world you may be legally discharged -even if you get a bunch of declarations of acquiescence to such thing even by the interested parties- of the results of your intervention taking the maximum authority in the recovery of the building. Society has a say in any potential damage to people, even if they don't care to be harmed.

 

[cap4000]

The ridge beam has two splices in it and was suppose to be one 40 foot 3 LVL section. The carpenter has also been terminated.

 

[cap4000]

Pitch is 2.75H : 12. Fairly flat for a residential roof. 2x10 rafters.

 

[msquared48]

Two splices? WhOOOOOah Nellie!!!!!!!!!!!!!

Immediately provide vertical shoring at the splice locations if the building nhas not yet been red-tagged. There is one of the problems and a big one! The splice was not done correctly in all likelihood, and never should have been used.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[BAretired]

If you recommend a fix, the roof will not be demolished and you will not be held harmless.

Provide a sketch and indicate where it is sliding.

BA

 

[dhengr]

And, a sketch or meaningful engineering details, dimensions, loads, etc. are not in your reply, so it will be difficult for anyone to give you any meaningful suggestions. MikeMcC hit on a few of the possibilities.

The best way to be held harmless is to walk away, right now. It can likely be fixed, but we can’t see what you have from here. You have to know enough about the structure to know what is important info. for a meaningful discussion. And, if you don’t, that may be another reason to walk away.

 

[msquared48]

And 2X10's for a 30 foot span? Seems to small. What is the local snow load?

I would recommend getting a competent structural engineer in your back pocket as soon as feasibly possible here.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[cap4000]

Ground snow load is 30psf. Husband and wife and 2 kids are currently living in the house. Walking away from this is easy for me at this point.

 

[msquared48]

Knowledge of the condition involves you and your professional liability at this point. You cannot and should not just walk away, but you can notify the local building juridiction of the condition in writing.

In my opinion, there could be a life-safety condition here, depending on any photos or on-site inspection made by a structural engineer.

The safety of the occupants is first and foremost here.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[msquared48]

2X10's spanning 30 feet with a 30 psf snow load is ridiculous too. Are you sure they were not spanning 15 feet or so to the ridge from either side, for a total building width of 30 feet? In that case, they would be OK.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[ToadJones]

....especially with children.
the situation sounds pretty dire.
Dont know where the house is located, but the case of collapses due to snow load, they are often abrupt.
Advise the adult occupants of what is on the line here. To hell with worrying about liability, you don't want to be reading about children killed in a collapsed house.

 

[cap4000]

My next stop is the Building Inspector however he was released and has one week left. A part timer is taking over.

 

[BAretired]

I agree with ToadJones. This is an emergency situation.

BA

 

[MikeHalloran]

I read the OP to say the building is 30 feet wide.

A sketch of the cross section would be helpful, just so everyone is talking about the same elephant.




Mike Halloran
Pembroke Pines, FL, USA

 

[4thorns]

Three of the most important people involved in the construction of this home apparently no longer have jobs! Based on the info in this thread I'd put this family up in my house just to get them out of the one they're in. I couldn't sleep at night with the knowledge that I know there is a possibility that these people are in danger of losing their lives and I may have been able to prevent it by trying to get them out.

My two cents.