Expert: Stephen Major (Owner--Major Design Group) - 8/12/2007

Question
Our garage roof at the peak has a 2 inch sag at the center. There appears to
be a crack in the  2 x 8 beam that spans the peak of the roof.  The crack is
just off  center of the span of the beam.

Is it possible to support underneath the cracked beam with a smaller steel
beam than a 2 x 8 ? What size metal beam would be equal in strength?

thank you!

Answer
Gregory,

Your question topic says truss replacement but your description seems to indicate a rafter (conventional) roof frame, with a ridge beam.  

If the roof is framed properly the ridge board is non-load-bearing.  It is really just a place holder against which the rafters lay.  There should be ceiling joists or collar ties in place (triangulation) to prevent the rafters from spreading (and sagging).  If this is not the case, for instance the frame is a cathedral, then you need to add the above elements or otherwise bolster the structure.

I can't help you with sizing a steel beam without knowing more information.  Is it possible to send photos of the structure?  Near, far, inside, outside views.  Send to info@majordesigngroup.com

I'll try to help.  Steve Major