Shingles alone aren't always enough.
Tile. Shake. Slate. Asphalt. No roofing material is completely immune to the ravages of cold, wet weather. Powerful sheets of windblown rain can force their way under roofing, and Ice damming is a common cause of winter roof leaks as well. Temperature differential (inside to outside) and improper ventilation or insulation often cause snow to melt and run down to the roof edge where it collects and refreezes. The ice mass then traps water behind it that backs up under shingles and penetrates the deck, resulting in interior damage. Moisture Guard Plus^® creates a barrier that helps prevent water from penetrating the roof deck and coming into your home. Without a waterproof barrier over your deck, moisture can penetrate the best roofing—and create costly damage to your home's interior. 

Moisture Guard Plus: helping your roof withstand nature's worst.
Moisture Guard Plus provides an extra layer of waterproofing protection you can use to help prevent damage from ice damming and windblown rain. The self-adhering modified-bitumen underlayment creates a watertight barrier by sealing to the deck and around nails to provide continuous protection year after year. You can use it to help protect the entire deck of a properly-ventilated roof or just in problem areas where water collects or drainage is slow. And since it can go under any roofing material from asphalt shingles to tile, you can enjoy maximum roofing protection with the architectural look you want.