Light Gage Stair Framing
Light Gage Stair Framing
(OP)
I have been asked to design some light gage stair stringers. Never been asked to do this before and it seems strange. Anyhow, this is what I have come up with (see attached).
Here is my question - Should I design the horizontal track for a 250lb point load or do you think the tread and underlayment material will distribute the load enough so that it is not an issue. When I check 20ga track using "CFS" software, it fails miserably. Even 18ga is overstressed by 70%. They are likely using 1" Armoroc http://ameriformllc.com/armoroc.asp or 3/4" plywood for the tread underlayment and then a wood tread on top.
I have talked to the author of the software in the past and he claims that the calc. for weak axis bending of a track is very conservative.
I hate to go to 16ga material as it intuitively seems overkill for this situation.
Thanks
Here is my question - Should I design the horizontal track for a 250lb point load or do you think the tread and underlayment material will distribute the load enough so that it is not an issue. When I check 20ga track using "CFS" software, it fails miserably. Even 18ga is overstressed by 70%. They are likely using 1" Armoroc http://ameriformllc.com/armoroc.asp or 3/4" plywood for the tread underlayment and then a wood tread on top.
I have talked to the author of the software in the past and he claims that the calc. for weak axis bending of a track is very conservative.
I hate to go to 16ga material as it intuitively seems overkill for this situation.
Thanks






RE: Light Gage Stair Framing
Dave
Thaidavid
RE: Light Gage Stair Framing
We are 20 of these in a condo loft building. Same ol' story- contractor did not have it in his budget so wants to save as much money as he can. (he thought they were going to be wood)
I guess the nice thing about 16ga is that they can use winged reamer screws to attach the underlayment that require 16ga material to work properly. I am not sure if the wings would break off prematurely in the Armoroc however.