A roof is more than shingles — it’s a system of components that work together to protect your home. Understanding the basics helps you have a more informed conversation when it’s time for an inspection or replacement.
Roof Deck (Sheathing) The foundation of your roofing system — the structural surface that everything else is installed on top of. Most modern homes use OSB (oriented strand board) panels. The deck needs to be sound, properly gapped, and free of soft spots before anything goes over it.
Drip Edge A metal flashing installed along the eaves and rakes that directs water away from the fascia and into the gutters. It’s one of the first things installed and one of the most overlooked — but it plays an important role in protecting the edges of your roof from water infiltration.
Ice and Water Barrier A self-adhering waterproof membrane installed at the eaves and in vulnerable areas like valleys and around penetrations. In Montana, code requires it to extend 24 inches inside the warm wall — providing protection against ice dams forcing water back up under the shingles.
Underlayment A synthetic protective layer installed over the entire roof deck beneath the shingles. It’s your secondary line of defense against water if shingles are ever compromised.
Starter Strip A purpose-built shingle installed along the eaves and rakes before field shingles go down. It seals the edges of the roof and prevents wind-driven water from getting underneath the first course of shingles.
Field Shingles The primary weather surface of your roof — what most people think of when they picture a roof. Installed in overlapping courses from eave to ridge.
Flashing Metal components installed at transitions, penetrations, and intersections throughout the roof — chimneys, walls, valleys, pipes, and skylights. Flashing is one of the most common sources of leaks when it’s improperly installed or fails over time.
Ventilation The system that moves air through your attic — intake at the eaves, exhaust at the ridge or through vents. Proper ventilation regulates temperature and moisture, protects your shingles, and is critical to the longevity of your roof and the performance of your insulation.
Ridge Cap Specialized shingles installed along the peak of the roof that cap the ridge and complete the weather seal at the highest point.
Pipe Flashings and Penetration Boots Sealed collars installed around every pipe, vent, or mast that penetrates the roof surface. There are different types for different applications — and using the wrong one is a common source of both water infiltration and safety concerns.