Final answer:
Collar ties should be attached near the top of the rafters to provide stability to the roof structure.
Step-by-step explanation:
Collar ties are horizontal members that are used to connect two opposing rafters. They help in preventing the roof from spreading apart under the weight of the roof load.
Collar ties should be attached near the top of the rafters. This ensures that they effectively distribute the load and provide stability to the roof structure. Attaching the collar ties near the top also helps to prevent the rafters from sagging or bending.
While collar ties can also be attached in the middle, but generally closer to the base, this is not as effective in providing stability to the roof structure.