Inspection, Testing, Defects and Repair
Inspection and testing
Candidates must know how to inspect felt roofs for blistering, wrinkling, ponding, lap failure, cracking, punctures, and detail defects. Testing methods include visual inspection, moisture surveys, flood testing of flat areas, and electronic leak detection where specified. Understand that inspection should follow a systematic route and be recorded.
Defects and repair
Know the common causes of failure: poor preparation, trapped moisture, cold laps, inadequate fall, movement, and UV degradation. Repairs must address the cause, not just the symptom. Local patch repairs suit isolated damage; full replacement is required where the membrane is at end of life or the defect is systemic.
Traps to watch
- Patching a blister without finding the moisture source.
- Assuming ponding is a membrane fault when it is a fall/design fault.
- Overlooking lap failure caused by contamination or cold application.
- Failing to record inspection findings and remedial actions.
Worked rule of thumb
Use I-C-R: Identify the defect, Cause (find the root), Remediate (repair the cause, then the membrane). A blister patched without addressing moisture will return; a lap repaired without cleaning will fail again. Record every finding.