Warranty Exposure
Few capital risks are as easy to create and as hard to discover as a voided roof warranty. A tenant improvement project rarely touches the roof on paper, yet the new rooftop units, gas lines, satellite mounts, and conduit penetrations that come with a build-out are precisely the kind of work that manufacturers cite when they deny a leak claim years later. For owners and asset managers, the gap between "the roof is under a 20-year warranty" and "the roof is actually covered for this leak" is where avoidable losses live. We advise treating every TI as a roof event, whether or not the lease or the contractor frames it that way.
Why TI Work Threatens Coverage
Most single-ply and built-up roof warranties from major manufacturers contain language requiring that any penetration, alteration, or repair of the membrane be performed by an authorized applicator and, in many cases, formally documented or pre-approved. A tenant's mechanical contractor setting a new rooftop HVAC unit does not know or care about that clause. They cut the membrane, flash the curb in whatever fashion their crew prefers, and move on. The work may even be watertight for several seasons. But the moment that detail leaks, the manufacturer's first request is the chain of authorization, and an unauthorized penetration gives them a clean basis to deny the entire claim, not just the failed detail.
The exposure compounds in multi-tenant assets where build-outs happen continuously. Each new tenant adds penetrations, walkways, and equipment, and each uncontrolled trade on the roof erodes the warranty a little further. By the time an owner faces a major repair, the question is no longer whether coverage exists but whether anyone can prove it still applies.
The Most Common Coverage-Killers
In our reviews of TI-driven warranty disputes, the same failure patterns recur. They are almost never exotic; they are ordinary construction shortcuts that nobody flagged as roof work.
- New rooftop equipment set on unflashed or improperly flashed curbs by a mechanical contractor rather than the roofing applicator
- Gas lines, conduit, and refrigerant lines run directly across the membrane on wood blocks or pavers that abrade and trap moisture
- Satellite dishes, signage, and antenna mounts fastened straight through the membrane without manufacturer-approved details
- Solar or screening attachments penetrating the deck without engineering or applicator involvement
- Construction debris, dropped fasteners, and foot traffic damage during the build-out that is never inspected or repaired
- Patches and tie-ins made with incompatible materials, such as asphaltic mastic on a TPO or PVC system
Where Lease Language Helps and Where It Fails
Owners often assume the lease protects them, and it should, but standard TI clauses are usually written around cost allocation and surrender condition rather than roof integrity. A lease that requires the tenant to restore at surrender does nothing to preserve the warranty during the term, and it gives the owner no leverage at the moment that matters, which is before the membrane is cut. The protections that actually work are operational, not contractual afterthoughts.
We advise that lease and work-letter language explicitly require any roof penetration or rooftop equipment installation to be performed or supervised by the owner's designated roofing contractor, at the tenant's expense, with a warranty maintenance certificate issued on completion. That single requirement converts a diffuse risk into a controlled, documented event and keeps the manufacturer relationship intact.
What We Require Before, During, and After a Build-Out
The discipline that preserves coverage is unglamorous and entirely repeatable. The objective is a clean paper trail showing that every membrane disturbance was authorized, executed correctly, and inspected, so that any future claim is met with documentation rather than ambiguity.
- Before: pull the original warranty and confirm the applicator-authorization and notification clauses; identify the active manufacturer and certified contractors in that market
- Before: require the tenant's design set to flag every proposed penetration and rooftop load, and route that scope to the authorized roofer for pricing
- During: stage and protect the membrane, restrict trade access to defined paths, and have the roofer flash all penetrations rather than the mechanical crew
- After: obtain a post-installation roof inspection, photo documentation of each new detail, and a manufacturer warranty continuation or maintenance certificate
- After: file the closeout package with the asset record so the next manager inherits proof, not guesswork
Treat the Warranty as a Capital Asset
A valid manufacturer warranty on a TPO, PVC, EPDM, or modified bitumen system is worth real money on the balance sheet, because it shifts the cost of a covered membrane failure off the owner. Letting it lapse through uncontrolled TI work is equivalent to writing off that asset without recording the loss. The failure is invisible until a claim is denied, which is why we recommend a periodic warranty audit across the portfolio, mapping each roof to its manufacturer, expiration, and known unauthorized alterations.
For owners weighing whether to enforce contractor restrictions on tenants, the calculus is straightforward. The incremental cost of routing penetrations through an authorized roofer is small and borne by the tenant; the cost of a denied claim on a deteriorating roof is borne by the owner and can run into six figures on a single building. Protecting the warranty is not administrative friction. It is one of the cheapest forms of capital risk management available on a commercial roof, and it is entirely within the owner's control.