When windows start leaking after lease-up, the carrier’s first inspection often finds nothing wrong. AMPR Consulting proves window installation defects across the building, runs the testing, and coordinates the experts and counsel.
Leaking Windows Usually Point to Poor Window Installation
Most calls come within the first several years after completion. Tenants report water at the sill corners, units go offline, and the builder’s insurer finds nothing wrong. One crew installs every window with the same methods, so the mistake behind the first leak usually repeats on every floor. That pattern turns a spot repair into a building-wide claim.
The installation defects AMPR documents most:
Window Defects
- Missing sill pan flashing: Water that gets past the frame drains into the wall instead of out of it.
- Reverse-lapped head flashing: The building wrap is tucked under the top fin instead of lapped over it, channeling water behind the window.
- Missing exterior flashing: Head and jamb flashing left out at the perimeter, so the joint between the frame and the wall has no backup.
- Shimming errors: Bowed frames, opened gaskets, and sagging sills.
- Sealant used as flashing: Caulk serving as the primary barrier, often incompatible with the stucco or frame.
- Blocked weep holes: Stucco buried over the fins, trapping water in the frame.
- Underrated units: A design pressure rating too low for the upper floors of a mid-rise.
- Sliders and balcony doors: No sill pans, or thresholds set below the deck waterproofing.
Three Carrier Arguments Against Window Claims and How AMPR Counters Them
The same arguments show up across water intrusion construction defect claims. AMPR is not a law firm. AMPR builds the technical record and coordinates with counsel, who make the policy arguments.
“Only the window work is defective.” Carriers cite the “your work” exclusion, which removes coverage for an insured’s own faulty work. AMPR counters with documented water damage around window openings: wet sheathing, rotted framing, and ruined drywall.
“The leaks started before the policy.” AMPR counters with a timeline built from occupancy dates, the first tenant complaints, and moisture data.
“Mold is excluded.” AMPR documents the loss as water damage caused by the defect, with mold as its consequence.
Case Study
Koreatown, Los Angeles: From an Under-$1,500 Valuation to a Settlement Without a Lawsuit
A seven-story multifamily building completed in 2023 started leaking soon after tenants moved in. The builder’s wrap carrier inspected, found nothing wrong with the windows, valued the claim at under $1,500, and moved to close it while the owner paid out of pocket.
- Stepped in: AMPR assembled a forensic building consultant, a cost consultant, and a forensic accountant.
- December 2024: AMPR ran three days of water and destructive testing with the carrier’s own consultant on site. Spray-rack testing produced leaks along an entire elevation. Openings showed missing or improper flashing with microbial growth behind it, plus shower pan, drain line, cladding, roofing, and planter waterproofing defects.
- About two months later: The primary carrier conceded that the exposure exceeded its policy limits, and a policy-limits demand went to the excess carrier.
- Damages: The preliminary estimate projected a 14 to 18 month restoration period, with lost rent and relocation built into the damages model.
- Summer 2025: The matter went to mediation and settled within a year and two weeks of AMPR stepping in, without a lawsuit.
“The insurer’s expert said there was nothing wrong with the window, and we were left paying out of pocket. On top of that, it felt like we were being told we still owed money because of the deductible… If you’re a developer dealing with a complicated claim, especially one that feels stalled or wrongly evaluated, AMPR is the team you want.”
Evan K., Developer, Koreatown
Frequently Asked Questions About Window Installation Defect Claims
The carrier’s expert said our windows are fine. Is the claim over?
No. Carrier inspections are usually visual and done from outside the wall. In Koreatown, after AMPR’s controlled testing, the carrier moved from an under-$1,500 valuation to a policy-limits concession. Here’s what to do when the carrier’s inspection doesn’t match what you’re seeing.
Will the builder’s insurance pay to replace the windows?
Liability policies generally pay for the damage defective work caused, not the cost of redoing the work itself. That’s why AMPR documents resulting damage to framing, drywall, and lost rent. Recovery often turns on your builder’s risk and wrap-up policies.
Should we repair the leaking windows now?
Stop active water entry right away, but don’t remove windows or open walls until the carriers can inspect. Repairs that discard the evidence can weaken the claim. Read what to do in the first 48 hours.
We have a sliding door leaking on several units. Is that part of the same claim?
Usually. Sliders and balcony doors fail the same ways windows do, and ASTM E1105 tests both. Leaks that repeat across units often signal one building-wide defect, not isolated repairs.
We found mold around windows. Does a mold exclusion end the claim?
Not necessarily. Mold behind the flashing is often proof that water got past the defect, and AMPR documents it as a consequence of water damage. Talk to AMPR before remediation removes the evidence, and see how to fight a denied construction defect claim.
What does AMPR need from us to start?
Your contracts and plans, the temporary certificate of occupancy (TCO) date, tenant work orders, every insurance policy, and every carrier letter. Whatever you have is enough to start. See how AMPR’s claims process works from first call to recovery.
What does it cost, and how long does it take?
The first conversation costs nothing, and engagement terms are discussed openly at that stage. Timing depends on the building, the number of carriers, and how quickly testing can be scheduled, and many matters resolve without a lawsuit. AMPR typically handles claims with $1 million to $40 million in defect damage. Here’s what a construction defect investigation involves.
Do we need to sue the builder?
Often, no. Koreatown resolved through mediation before any lawsuit. Filing first usually triggers cross-complaints and years of discovery, which is what hiring an attorney before a consultant costs you. Deadlines still apply, so learn why the discovery date determines how long you have to act.
Does this apply to HOAs, insurers, and contractors?
Yes. Boards can get HOA construction defect support for shared-liability window failures. Insurance professionals get a witnessed test record for coverage decisions. Contractor defect claims benefit from testing that separates product failure from installation failure. Owners and developers of newer multifamily buildings bring AMPR most of its window work.
Your Window Claim Needs Evidence Before It Needs an Argument
Complete the form with your building’s location, completion date, and where the carrier stands. AMPR will review the claim and outline the testing needed to prove it.
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