Decking (sheathing)
The structural panels nailed to trusses or rafters. Shingles attach to decking; soft or spongy spots often mean moisture reached the wood.
Underlayment
A layer between decking and shingles that sheds water if outer roofing is compromised. Local codes specify acceptable types and coverage.
Ice and water shield
Self-adhered membrane used in vulnerable transitions such as eaves, valleys, and penetrations. Even in Texas it appears where codes or manufacturer systems require extra sealing.
Flashing
Metal or membrane pieces that bridge gaps where roofs meet walls, chimneys, skylights, or lower roofs. Failed flashing causes many slow leaks.
Drip edge
Metal flashing at roof edges to steer water away from fascia and into gutters.
Valley
Inside corner where two roof planes meet. Water concentrates there, so valleys wear faster than open fields.
Ridge and ridge vent
The ridge is the horizontal peak where two slopes meet. Ridge vents are exhaust openings that work with intake vents lower on the roof or soffits.
Fascia and soffit
Fascia boards face outward behind gutters; soffits cover the underside of eaves. Both affect how moisture and pests reach the roof edge.
Square
Contractors often estimate asphalt bundles in “squares.” One square equals one hundred square feet of roof area covered to manufacturer specification.
Related reading: repair vs replacement and what inspections cover.