Product Spacing Calculator

As with all rigid materials, expansion is a significant design consideration. The system of gutters, downspouts and their supports must have the flexibility and strength to acommodate expansion.

Expansion joints are suggested for gutters to allow movement caused by thermal changes. Long, straight runs should not have expansion joints spaced more than 50 feet (15 m) apart and no more than 25 feet (7.5 m) from any fixed corner. Some types of expansion joints act as a water dam in the gutter; therefore, the number and placement of downspouts will be influenced by the type of expansion joint used.


Choose the type of metal used with the thermal movement compensator. The metal chosen must be the same metal as the gutter.


The calculations provided above serve the purpose of being a guideline and design aid to the roofing and waterproofing professional and are NOT as intended substitute for sound technical judgement of an experienced professional.