Cold-formed steel framing in Massachusetts

[stevenspm]

Hello,
I have design a facade rehab in Framingham Mass, and one of the framing subs believes that the requirements are min 16ga studs @ 18" oc. I have looked through both chapters 16 and 22 of the IBC and the Massachusetts amendments to the IBC2009 and I have not found any reference to this requirement.

Has anyone heard of such a requirement or is this a case where the subs are misinformed/thinking about a previous project? I am inclined to believe the subs are thinking about past projects since I did not find any reference nor did the town make any comments about it.
Thank you

 

[CANPRO]

What exactly is the application? How tall is the wall? He might be looking at the span tables provided by the manufacturer...that's what my steel stud clients typically do to get an estimate for the stud requirements.

16 Ga sounds heavy to be any kind of blanket minimum requirement. And why use 16 Ga @ 18"? What is the depth of your stud for that matter... Can you get better value with a lighter stud at a closer spacing?

I'm not familiar with the IBC, so I'm not sure what the relevance of the chapters 16 and 22 are. But, if this is your design shouldn't the stud size/spacing be based on your calculations?

Personally, I would have just asked the contractor where he got that requirement. I'm curious now...did you specify something lighter than this? If my clients say they feel the steel studs I have spec'd are too light and want to use heavier studs (this has happened) it is generally a pretty short conversation because I really have no problem with it.

 

[TDIengineer]

18 Gauge studs at 16" o.c. sounds more like it..

Wind loading will govern your stud design assuming non-bearing facade studs. I would check with the local building department what code has been adopted and what is their design wind speed.

No local government standard is going to dictate a size of stud and spacing... it may dictate loads and wind speeds, etc.. but not force the design. What if your studs spanned 30'? Just use 16 Ga at 18"? Makes absolutely no sense. Don't listen to the sub.

 

[wannabeSE]

Also, check the requirements for the cladding. Maybe some rainscreen requires the 16 GA @18".

 

[Hokie93]

The minimum stud thickness for masonry veneer anchored to steel stud backing is 18 gage (43 mils). This requirement is found in Chapter 6.2.2.7.3 of ACI 530-08. I suspect this is what the subcontractor had in mind. ACI 530-08 is referenced by IBC 2009, of course.

 

[TDIengineer]

I am assuming they have found that the reliability of screw pull-out from 20 gauge isn't that great, too thin for consistent thread bite... And the spacing of the lateral ties probably don't calc out with 20 gauge backing.. This is why I would guess the ACI added this provision to the code...

I usually specify at least 16 gauge studs minimum where there is a heavy veneer facade such as brick or tile.

 

[mijowe]

The 18" oc number is sign that the person is misinformed. Nobody would require a spacing that did not work with 48" sheathing.

The Brick Institute, and as indicated above, publishes a minimum of 18 gage for studs backing up brick.

http://www.gobrick.com/portals/25/docs/technical notes/tn28b.pdf

 

[ztengguy]

tell the sub that he can do what he wants. Just needs to redesign and stamp the drawings, otherwise, its as shown on the plans without any legitimate proof that its wrong.

 

[brut3]

I've reviewed quite a few rainscreen and cladding system drawings that have specified the same stud thickness and spacing. I believe the thickness and spacing of the exterior framing members comes from multiple cladding manufacturers typical attachment details.

Most cladding manufacturers prefer 16 gauge framing to attach their systems to for mechanical fastener pullout purposes. As previous posters have specified 16" o.c. is a typical exterior framing member spacing.