A roof system that sheds water and breathes

An overlay is allowed in many jurisdictions when there is only one existing layer, the decking is sound, and the existing shingles are flat rather than curled or buckled. It saves tear-off labor and disposal cost, but it hides deck damage, adds dead load, and traps heat, which usually shortens the new layer's service life. It also raises the cost of the next roof, since two layers then have to come off. Local code sets the limit, so it is worth confirming before assuming an overlay is an option.

Functional hail damage on asphalt shows as soft, bruised spots where granules are knocked away and the mat beneath has been fractured; the spot often feels spongy under a thumb. Wind damage shows as creased or lifted tabs, missing shingles, and displaced ridge caps. Dents on gutters, vents, and other soft metal confirm that impact occurred, but the roof surface still has to be evaluated on its own, and dated photographs taken soon after the event matter if a claim follows.

Attics collect warm, moist air from the living space below, and without airflow that moisture condenses on the underside of cold sheathing. A balanced system draws cool air in at the soffits and exhausts it at the ridge, keeping the deck closer to outdoor temperature. Codes commonly size the total net free vent area at roughly one square foot per 150 square feet of attic floor, with a reduced ratio permitted when intake and exhaust are properly balanced or a vapor retarder is present. The payoff is less winter ice damming, less summer heat aging the shingles from beneath, and far less risk of mold and sheathing rot.

Often not. A large share of leaks originate at flashing, pipe boots, skylight curbs, or valleys rather than in the field, and those details can be rebuilt on their own. The deciding questions are the roof's age against its expected service life, whether granule loss and curling are widespread rather than local, and whether the decking has already been compromised. A roof in its last few years is usually better replaced than repeatedly patched.

It is a self-adhering rubberized membrane bonded directly to the deck in the most vulnerable areas, with the field underlayment lapped over its upper edge, and it seals around nail shanks instead of simply lying loose on the deck. It belongs along the eaves, in valleys, and around chimneys and skylights, where meltwater backing up behind an ice dam or wind-driven rain can travel uphill under the shingles. Cold-climate codes commonly require an ice barrier at the eaves, extending a specified distance inside the exterior wall line. In milder regions it is not usually mandatory, but it is still worth having in valleys and at penetrations.