What Is a Secondary Water Barrier on a Roof?

A secondary water barrier is an additional waterproof layer installed beneath roofing materials. Its purpose is to prevent water from entering the home if shingles, tiles, or metal panels are damaged during a storm.

This extra protection is especially valuable in hurricane-prone areas like Florida.

How Secondary Water Barriers Work

Normally, the roof covering is the first defense against rain. However, during severe storms, roofing materials can loosen or break.

A secondary water barrier creates a backup layer of protection by sealing the roof deck and preventing water intrusion.

Benefits of Secondary Water Barriers

Advantages of installing a secondary water barrier include:

• Reduced risk of interior water damage
• Improved hurricane protection
• Potential insurance discounts
• Added protection during roof failures

Because of these benefits, many modern Florida roofing systems include this feature.