ELD During Construction
When Is the Right Time to Perform Electronic Leak Detection During Construction?
A commercial roof might be finished, but construction work often continues long after the roofing crew leaves.
Mechanical contractors still need to install equipment. Electricians may need rooftop access. Additional penetrations, equipment deliveries and foot traffic can introduce damage to a membrane that was installed correctly.
That raises an important question for general contractors, roofing consultants and building owners: When should Electronic Leak Detection (ELD) be performed to provide the most value?
The answer isn't necessarily one final inspection before the building is occupied. Depending on the project, testing at key construction milestones can help identify membrane breaches, document findings and provide an opportunity for repairs before the next phase of work begins.
Why Timing Matters
In an October 2026 article published by Professional Roofing, industry experts Jason Wilen and Nick Casaletto highlighted a growing challenge in commercial roofing: responsibility for roof performance often becomes fragmented across multiple trades and construction phases.
Their article, Find a Champion, emphasizes the need for better coordination, consistent quality control and clear accountability throughout construction.
These same challenges make the timing of ELD testing important.
Consider a newly installed roofing membrane that undergoes ELD testing and passes without any identified breaches. Two weeks later, another trade installs rooftop equipment, requiring additional foot traffic and modifications.
The original test documents the condition of the membrane when the survey was performed. It doesn't account for damage that may occur afterward.
That's why ELD should be treated as part of the construction quality assurance process, not simply a final checklist item.
Three Key Opportunities for ELD Testing
1. After Membrane Installation, Before Additional Work
One of the most valuable opportunities for ELD testing is after a roofing or waterproofing membrane has been installed and the designated area is ready for testing.
At this stage, testing can help identify breaches before additional construction activities complicate access or introduce new damage.
Testing before the installation of pavers, landscaping or other overburden can be particularly useful. Once these materials are in place, accessing the waterproofing membrane may become more difficult, and testing options may be more limited.
The appropriate testing method and timing depend on the membrane assembly, site conditions and accessibility. Early coordination with an ELD specialist helps project teams determine when an area will be ready.
2. After Other Trades Complete Rooftop Work
A completed roof often becomes a work area for several other construction trades.
HVAC installations, electrical work, equipment placement and new roof penetrations can expose membranes to damage, even when contractors take appropriate precautions.
For this reason, additional ELD testing may be warranted after significant rooftop activity.
A follow-up survey can help identify breaches introduced since an earlier test, allowing repairs to be addressed before construction advances further.
Not every project requires the same testing frequency. The amount of rooftop activity, project requirements and level of risk should guide the decision.
3. Before Final Construction Handoff
Final ELD testing can provide valuable documentation of membrane condition before the project transfers to the building owner.
This is especially relevant when rooftop work has continued after an earlier inspection.
A pre-handoff survey helps document the areas tested, the conditions present during the survey and any breaches identified.
If repairs are necessary, the construction team can coordinate corrective work and appropriate verification before closing out the roofing scope.
Scheduling this work before the final days of construction also leaves time to address findings without creating unnecessary pressure on the handoff schedule.
What About Projects Built in Phases?
Many commercial buildings don't have the entire roof completed at the same time.
One section may be ready for testing while another remains under construction. On larger projects, waiting for the entire roof to be finished may mean delaying verification of areas that are already accessible.
A phased testing plan offers another approach.
Project teams can coordinate ELD surveys around completed roof sections, documenting which areas were tested and when. As additional sections are completed, further surveys can be scheduled.
If previously tested areas undergo additional construction activity, the team can evaluate whether follow-up testing is appropriate.
The important consideration is maintaining a clear record of tested areas and construction activity so everyone understands what the results represent.
Five Questions to Ask Before Scheduling ELD
Planning ELD testing early helps general contractors, roofing contractors and consultants avoid scheduling conflicts.
Before establishing the testing schedule, consider these five questions:
When will each roofing or waterproofing area be complete and accessible? Identify the construction milestones when testing can be performed.
Will additional materials be installed over the membrane? Coordinate testing before overburden or other materials limit access whenever appropriate.
What other trades will be working on the roof afterward? Identify activities that may justify additional testing.
Are the membrane assembly and site conditions suitable for testing? Confirm the appropriate ELD method, access requirements and necessary surface conditions with the testing provider.
Who is responsible for addressing and verifying identified breaches? Establish how findings will be communicated, repaired and checked before the next construction milestone.
These questions help make ELD part of the construction plan rather than a last-minute scheduling request.
ELD Is One Part of a Complete Quality Assurance Process
Electronic Leak Detection is designed to help locate breaches in compatible roofing and waterproofing membranes under appropriate testing conditions.
It complements visual inspections and other roof assessment methods, but it does not replace them. ELD also doesn't provide a permanent guarantee against future damage.
A properly planned survey provides information about the areas tested at a specific point in time. Understanding that distinction helps construction teams determine when additional testing may be useful.
Plan ELD Testing Around Your Construction Milestones
The best time to perform Electronic Leak Detection depends on the project's construction schedule, rooftop activity and quality assurance objectives.
For roofing contractors, testing immediately after membrane installation can help verify its condition and document findings before other trades begin work. For general contractors and building owners, testing after significant rooftop activity or before final handoff may provide additional value.
While testing at multiple milestones offers opportunities to identify damage throughout construction, even a single well-timed survey can provide valuable documentation.
Honza Group Inc. works with roofing contractors, general contractors, consultants and building owners to determine the appropriate ELD testing approach and timing.
Don't leave ELD testing to the last minute. Plan it around the milestones that matter most to your project.
Sources referenced in this post:
1. ASTM International (2025) ASTM D7877-25: Standard Guide for Electronic Methods for Detecting and Locating Leaks in Roofing and Waterproofing Membranes
2. ASTM International (2024) ASTM D8231-24a: Standard Practice for Low-Voltage Electronic Scanning
3. IIBEC (2019, updated 2021) Technical Advisory 018: Electronic Leak Detection
4. IIBEC (2025) Technical Advisory 025: Roof System Functionality
5. Honza Group Inc. Testing Through Overburden
6. Professional Roofing (October 2026) Find a Champion, by Jason Wilen and Nick Casaletto
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