Map drains, slopes, penetrations, seams and ponding areas.
V18 — specialized system
Low-slope or flat roof
Treat membrane, insulation, air/vapour control, drains, overflow, parapets and penetrations as one assembly.
Checked: 2026-08-22
Replacing membrane without understanding moisture/insulation can trap a problem below the new roof.
Deflection, major ponding, wet insulation or unknown structure: professional investigation before recover.
Useful tools / data
- Drain/slope plan
- Post-rain photos
- Repair history
What the professional checks
- Assess moisture/insulation/deck
- Design drainage/details
- Verify membrane/substrate compatibility
Sources and limits
Triage prepares decisions and quotes; it does not replace permits, calculations, inspections or regulated trades.
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 →
Tools related to this issue
V14
Systems to check before closing the work
V14 connects envelope, air, fire, structure, water and code instead of treating each project in isolation.
V16
Advanced diagnostics to cross-check
V16 connects water, soil, climate, safety, materials and seasonal use to existing projects.
V17
Specialized systems to cross-check
V17 completes gas, soil, water, fire, climate and structural interfaces.
V19
Edge systems to integrate into the project
V19 covers interfaces that become important when multiple home systems interact.
Advanced systems and special cases
Checks that change sequencing, risk or which professionals must be coordinated.
V26
Often-overlooked service interfaces
V26 connects systems that cross utility, plumbing, HVAC, envelope and metering boundaries.
V27
Project risks and overlooked interfaces
V27 connects payment, water, envelope, ventilation and jobsite details that often create costly surprises.
V28
Finish and service details to verify
V28 connects small details that become costly once finishes are closed.
V30
Shared, access and specialized interfaces
V30 connects projects where multiple systems, owners or rules meet.
V32
Post-disaster and legacy systems
V32 connects contamination, storm damage, legacy materials and recommissioning before rebuilding.
V47
V47 interfaces not to miss
These details are small on a drawing but can control water, structure or durability.