Second shingle layer or full tear-off?
Compare overlay versus tear-off based on deck, weight, ventilation, flashing, shingle condition and ability to expose hidden defects.
VERT / GREEN
Inspect attic, leaks and visible condition before quoting.
JAUNE / YELLOW
An overlay hides the deck and adds weight; NRCan generally recommends removing existing shingles when reroofing.
ROUGE / RED
Soft/rotted deck, active leak, multiple layers or flashing that needs rebuilding: tear off and inspect before new roofing.
Quick triage
What the professional checks
The roofer checks layer count, decking, flashing, ventilation, penetrations, product warranty and code/manufacturer constraints.
Official sources
Checked 2026-08-23
Related path
Continue with the right tools
These links connect this page to the next useful checks and decisions without repeating the full content.
Connect symptoms to the enclosureStart from condensation, staining, odours or movement before choosing a repair.Open →Adapt the enclosure to climateConnect heat, cold, water, wind and wildfire to building priorities.Open →Assess overall resilienceReview water, climate, safety, autonomy and records with a local score.Open →Screen hazardous materialsIdentify situations where work should stop and testing is needed before disturbance.Open →Open climate guidanceReview climate constraints relevant to assemblies and materials.Open →
Manage the project through closeout
V14
Systems to check before closing the work
V14 connects envelope, air, fire, structure, water and code instead of treating each project in isolation.