Why the roof warranty matters to a solar project
A commercial roof is a system with a manufacturer behind it. The owner often holds a warranty covering leaks and defects for a period of years, and that warranty comes with conditions. Many roofing manufacturers restrict who may work on the roof, what may be fastened to it and how, and require notice or inspection when penetrations are made. If a solar project ignores those conditions, the owner may lose coverage, and a leak above a tenant's inventory becomes a dispute among the owner, the roofer and the solar contractor.
The warranty is therefore a design input, not a legal footnote. It can determine whether the array is ballasted or attached, where penetrations are allowed, and whether a roofing contractor must be on site. The survey is the best moment to learn what the constraints are.
Identify the membrane
Different membranes behave differently under foot traffic, heat, ballast and fasteners. The common types include TPO, PVC and EPDM single-ply membranes, modified bitumen, built-up roofing with gravel or a cap sheet, and standing-seam or other metal roofs. For each, record:
- Type and color, photographed in the field and at a seam or lap.
- Attachment method, where discernible: mechanically attached, adhered or ballasted.
- Insulation and buildup, from cores, previous repair notes or the roofer.
- Age. Ask for the installation date, the roofer's records and any repair history.
- Condition. Ponding, blistering, shrinkage, open seams, punctures, exposed fasteners, deteriorating flashing and areas that feel soft underfoot.
Roof age and remaining life deserve their own line in the record. An array with a long design life placed on a roof near the end of its service life means a re-roof with the array in the way, and removing and reinstalling modules is a significant cost. Some owners choose to re-roof before installing solar for exactly this reason.
Find the warranty and the contact
Ask the owner for the warranty document, the manufacturer's name, the roofing contractor who installed the system and the current status of coverage. Record whether the warranty has transferred, expired or been affected by past repairs. Capture the contact for the roofing contractor, because many manufacturers require an approved or certified contractor to make penetrations or to inspect the roof before and after the solar installation.
Do not assume. Warranty terms vary by manufacturer and by contract, and the survey crew is not in a position to interpret them. The job is to collect the documents and the names so that the owner, the roofer and the engineer can work out the rules before design is fixed.
Penetrations, ballast and attachments
The membrane influences the mounting approach. Ballasted racking avoids penetrations but places weight and friction on the membrane, so protection layers may be needed. Attached racking uses fasteners through the membrane into the deck or structure, with flashing details that the roofing manufacturer may need to approve. Adhered systems on some membranes use specific products. The structural limits that decide between them are covered in our note on roof structural assessment for commercial solar.
- Locate every existing penetration, curb and flashing, because they set where new ones can go.
- Record membrane details around curbs and parapets, where leaks begin.
- Note foot-traffic paths and walkway pads, since construction creates traffic the roof was not designed for.
- Flag any areas of wet insulation or poor condition that should be repaired before solar.
Drainage and the membrane
Ponding degrades membranes, and an array that blocks drainage can create it. Record drains, scuppers, overflow outlets and slope directions so row layouts leave water paths open. Standing water that is already present before the project should be photographed and located, so any later argument about whether solar caused it can be settled with evidence.
Coordinate with the roofer early
Treat the roofing contractor as a project stakeholder. A short conversation during design is cheaper than a stop-work notice during construction. Typical questions include: what attachment methods are acceptable, what flashing is required, whether pre-installation and post-installation inspections are needed, and what the warranty position is if the array is later removed for re-roofing.
What to bring to the owner conversation
Roof warranty questions are easier to resolve when the owner is asked clearly. A short list works well: Do you have the roof warranty document and who issued it? Who installed the roof, and are they still in business? Has the roof been repaired or modified, and by whom? Are you planning a re-roof within the life of the solar system? Do you have a preferred roofing contractor for solar work?
Record the answers verbatim, along with the date and the person who gave them. If the owner does not know, that is itself a finding, and it tells the project team that the warranty status needs to be researched before design is finalized. Owners often appreciate being asked, since it signals that the solar contractor is protecting their asset instead of only focusing on the array.
Finally, keep the roofing questions separate from the structural ones in the record. They have different decision makers, different timelines and different risks, and mixing them makes both harder to resolve.
What a survey provider should deliver
The roof section of a good commercial record contains the membrane type, age and condition notes, warranty holder and contact, a dimensioned roof plan with penetrations, drains and parapets, and photographs of anything unusual. Solar Survey AI captures this as part of a commercial on-site survey, with roof, structure and electrical room in one visit and the deliverable 48 hours after the survey. The engineering that follows, C&I design and engineering, works from the same record. The full set of roof items is listed in the commercial survey requirements.