Engineering Details by MiTek Engineering

A few details from MiTek for informational purposes;


Good information Marcel.

This brings up a truss issue that 90% of the contractors and most city inspectors are not aware of, especially on girder trusses. The detailed truss drawings the contractor receives has bearing reactions listed. There will be gravity loads acting downward, wind uplift loads and possibly some horizontal loads. Any uplift load over 200 lbs will require some type of hold down. The IRC states three toenails will be enough to restrain wind uplift up to 200 lbs. So no need for the standard H1 hurricane clips, which were only rated at 175 lbs. The larger houses with the complicated roof trusses will have some standard trusses that can have wind uplift loads exceeding 500 lbs, however the multi ply girder trusses can easily exceed 2000 lbs and more if your in a high or hurricane wind zone. These girder trusses will need a continuous tie down system that transfers the wind uplift load down to the foundation. Very expensive to retrofit if it was missed during construction. Truss companies disclaim this as the building designer’s responsibility. But on a residential house how many people hire a designer? If you’re doing phase inspections and you can’t read truss plans you should take the time to learn IMO.