Rafter ties are always required unless the roof has a structural self supporting ridge or is built using engineered.
Roof rafter tie.
In most homes the ceiling joists also serve as the rafter ties.
High horizontal ties in the upper third of the roof under compression definition of mid span rafter ties.
Collar ties prevent uplift.
Nail one end of the tie into the rafter with 3 inch nails.
This means that if you secure one end of the collar tie to the left side of a roof rafter you will nail it to the right side of the adjacent rafter.
We detail these below.
Rafter ties prevent spreading.
The tie will go from one side of a roof rafter to an adjacent rafter but on the opposite side.
Compare this with a similarly framed 12 12 roof that has similar loads.
Secure the opposite side in the same manner.
Definition of collar ties.
Truss and rafter tie downs are used for wood construction and wood framing projects.
With the first collar tie in place you will follow the same procedure.
Other facts about rafter ties.
Contrary to popular belief collar ties are not there to support rafters or to keep walls.
Moving the rafter ties up only 16 inches from the plate the maximum allowed by code increases the tie force from 1 440 pounds to 2 160 pounds.
Simpson strong tie category roof truss and rafter connectors ties and straps for cold formed steel construction.
Definition of low rafter ties.
A tension tie in the lower third of opposing gable rafters that is intended to resist the outward thrust of the rafter under load.
Measure for each new collar tie.
Located horizontally in the middle of the rafter s run or horizontal span neutral.
Located in the bottom.
Step 4 continue installing collar ties.
Contrary to popular belief collar ties are not there to support rafters or to keep walls below from spreading under the weight of the roof.
Figure 2 is an illustration of a roof constructed using rafter ties.