How to Place Collar Ties on Roof Rafters

Roof Rafters
What You'll Need
2 x 6 lumber
Tape measure
Circular saw
3-inch nails
Roof jack

Installing collar ties on your home's roof rafters will help to keep the integrity of the home intact. The collar ties are used to strengthen the roof rafters to prevent them from buckling, or sagging, under the weight of the roof. This is especially important if the home is in the northern climates where snow accumulates on roofs, or if there are multiple layers of roofing materials. Placing collar ties on roof rafters is not a hard process and can be completed with simple tools.

Step 1 - Determine the Location of Collar Ties

Collar ties are usually placed in the attic area of homes. They are secured about three-quarters of the way up the roof rafters. Check the attic so that you can get a better look at where the roof rafter collar ties will be installed. Measure the distance between adjacent roof rafters so that you will know the amount of lumber to purchase.

Step 2 - Cut Collar Ties

In order to install the collar ties, you will need to cut the 2 by 6 lumber to length. The measurement must be taken from a point at 3/4 of the way up the roof rafters to the same point on an adjacent rafter. Depending on the roof, this measurement may be different for each rafter. For added strength, you can stagger the placement of the collar ties from between 1/2 to 3/4 of the way up the rafter. With the first measurement, cut the 2 by 6 lumber to the correct size. Make the cut with the wood on a pair of saw horses and a skill saw.

Step 3 - Install Collar Tie to Roof Rafters

Take the collar tie up to the attic and lift it into position to check for the fit. The tie will go from one side of a roof rafter to an adjacent rafter but on the opposite side. 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. Nail one end of the tie into the rafter with 3-inch nails. Secure the opposite side in the same manner.

Step 4 - Continue Installing Collar Ties

With the first collar tie in place, you will follow the same procedure. Measure for each new collar tie and then install it by nailing it to the roof rafters. For extra-large roofs it is recommended that every other roof rafter has double collar ties installed on them.

Step 5 - Repairing Sagging Roofs with Collar Ties

If your roof is already sagging by the pressure of the roof, you can use the collar ties to help the roof rafters bend back into shape. Use a roof jack on the sagging roof rafters to raise them back into position. Measure for the collar tie and install it in the regular method. However, because the rafter has already been weakened, you will need to add another collar tie directly under the first one.