Sky Lift "Roof Riser Hardware"

[Christopher C]

Hello everyone,
I have a client who has presented me with a system meant for supporting patio cover beams by stubbing up from the wall plates through the roof assembly. Here is the product...

https://www.skylifthardware.com/resources/display/faq

My first reaction was a little cringe-y. I see potential for torsion on the top plate, which would lead to water intrusion issues. However, I can see the possibility for increasing the rigidity of the patio cover structure, and transferring any remaining moments to the roof assembly. In other words, I feel like I can make this work with some modifications. Have any of you used this system or designed anything similar? Do you have any thoughts or advice?

As always, thank you all in advance for your time.

 

[MotorCity]

Fitting 2 fasteners across the 4" dimension of an exterior 2x4 wall seems highly unlikely. Fasteners penetrating a shingle roof = bad idea. What is the lateral system of this thingy to resist lateral wind loads? Don't see any sort of bracing, or alternatively, moment connection between base and top of wall does not seem realistic. Would not use it on my house.

 

[dhengr]

Christopher C:
I’ve seen these before, they were imagined and developed by some deck builder or carpenter who had to put a few roofs on some existing decks. They really only paid some attention to a light vert. roof load and its transfer to the house structure, and as usual with most of these people completely ignored any lateral loads, or real lateral tie-in to the bldg.. Their biggest issue, and greatest claim to fame was that they used a std. adjustable plumbing vent boot on the correctly sized pipe vert. member as a means of flashing the roof penetration. That roof penetration and flashing it has always been a problem when it is not within a weather protected space. It seems reasonable that such a system can transmit the vert. loads, as long as the structure above and below provide an adequate and complete load path. But, you are pretty much on your own when it comes to providing some lateral stability to that roof system, in all directions.

 

[Mjkkb2]

Never used it but they do have a building official letter on the website stating the testing for lateral loads is available upon request. I do agree that there's no means for lateral forces to transfer safely down into the shear walls/braced panels etc... This doesn't mean it wouldn't work but I'd have a hard time putting numbers to it and signing on the dotted line.
Maybe as means of modification some light gage straps could be used to provide some bracing between these posts?

 

[JAE]

I wouldn't count on them to resist lateral loads.

Perpendicular to the supporting wall, you could get SOME level of resistance via the little lag screws at the double top plate but I'd worry that the double top plate isn't adequately attached to sheathing, studs, etc. to carry that load further.

Parallel to the wall, perhaps a little better mechanism there but still "iffy".

Their statement about this:
[red]"The bracket is to be incorporated into a designed system. It is the responsibility of the installer to design and calculate.
The SK-24-HD is engineered for seismic and lateral loads. The lighter bracket relies on the outline posts in combination with alternate bracing."[/red]
appears to place the burden on the designer while at the same time providing a nice sounding sales pitch that it "is engineered for seismic and lateral loads.". Sure, whatever.



Check out Eng-Tips Forum's Policies here:
faq731-376