cracked trusses in residential attic
cracked trusses in residential attic
(OP)
what caused trusses to crack (see attached pics)? Poor ventilation in attic and widespread mold growth. 2x4 trusses at 24". 5:12 pitch standard construction. Do you think high humidity/poor ventilation could weaken wood enough to crack it? or was it weight of ice and snow? wavy sheathing observed from top of roof surface. to me, all is pointing toward origin of cracks and dipping of top chords/sheathing to poor ventilation. No h-clips observed to attach sheathing.





RE: cracked trusses in residential attic
But the top cords split at the bottom indicates overload in a down direction. Splitting the cord at the knot (stress concentration). I would suspect a high wind load event or a point load from a stack of shingles during roofing.
RE: cracked trusses in residential attic
I would agree with boo1 - a local overload on that particular truss if no other truss shows any signs of distress. The knot could have been the weak spot that allowed the crack to start.
How old is the home? Where is it located (snow load)?
The last attic I investigated for solar PV panels had excessive mold as well - some idiot thought that venting the bathroom exhaust fan into the attic space was okay.
Ralph
Structures Consulting
Northeast USA
RE: cracked trusses in residential attic
RE: cracked trusses in residential attic
RE: cracked trusses in residential attic