A useful leak review connects reported symptoms with weather, locations, assemblies, repairs, warranties, testing, interior damage, and the capital decision ahead.
Begin with the leak pattern—not the word “roof”
An interior stain below the top floor may suggest roofing, but water can enter at parapets, copings, wall joints, windows, façade cracks, rooftop equipment, penetrations, drains, expansion joints, terraces, balconies, or transitions between assemblies. It can travel along decks, framing, insulation, ceilings, piping, and interior construction before becoming visible. Condensation or a plumbing release can create a similar symptom.
Federal roofing guidance specifically cautions that reported roof leakage may originate at adjacent walls, windows, or mechanical units. A baseline property condition assessment can identify visible conditions and reported history; it should not claim a source that the available evidence and agreed scope do not establish.
Reconstruct the chronology property teams already know
The record should identify the date and location of each reported event, weather and wind direction where known, occupied area affected, duration, interior damage, temporary response, contractor involved, exterior location treated, materials used, warranty notification, reported result, and whether the symptom returned. Floor plans, roof plans, elevation drawings, photographs, work orders, proposals, invoices, complaint logs, insurance records, and interviews make the pattern easier to see.
A repair invoice proves that work was billed; it does not by itself prove the source was correctly diagnosed or that the condition remained resolved. Repeated treatment at one location, shifting symptoms after repair, or recurring complaints under similar weather can be more informative than one recent dry inspection.
Read the enclosure as connected assemblies
The field review should consider roof coverings and flashings, penetrations, curbs, drains and overflow paths, ponding, parapets, copings, sealants, masonry, cladding, joints, windows, louvers, balconies, terraces, below-grade interfaces, and visible interior consequences as applicable to the property. Transitions deserve particular attention because water, air, and vapor control layers have to connect across different materials and trades.
Access, height, safety, overburden, occupied spaces, finishes, concealed construction, weather, recent repairs, and the limits of visual observation affect what can be concluded. Binocular or ground-level review, accessible roof observations, and representative interior access are not equivalent to a close-up façade survey, probe, or controlled water test. The report should describe the actual coverage.
Choose investigation tools for the question
Targeted follow-up may include close-up access, exploratory openings, roof cores, infrared or capacitance moisture surveys, electronic leak detection, controlled spray testing, flood testing where appropriate, sealant or material testing, drainage evaluation, interior moisture mapping, laboratory analysis, or monitoring during weather. Each method has prerequisites and limitations and should be designed by qualified professionals for the assembly and decision.
WBDG guidance notes that moisture-detection methods can identify areas consistent with elevated moisture without necessarily locating a membrane breach; condensation, construction moisture, assembly differences, and test conditions can affect results. An anomaly should be interpreted with visual review and, when appropriate, confirmatory sampling or openings rather than converted directly into a repair quantity.
Preserve warranties without mistaking them for condition
The diligence record should identify available roof, façade, window, sealant, coating, contractor, and manufacturer warranties; start and end dates; covered assemblies; exclusions; transfer requirements; approved service providers; notice procedures; required maintenance; prior claims; and open responses. Unauthorized repairs or missing maintenance records may affect coverage, but that determination belongs with the warrantor, owner, and counsel as applicable.
A current warranty can be valuable and still fail to cover interior damage, consequential loss, design conditions, adjacent assemblies, maintenance, abuse, drainage, or workmanship outside its terms. Conversely, an expired warranty does not establish that replacement is immediately required. Condition, history, repairability, remaining service, and ownership plans still need to be evaluated.
Turn the history into a bounded capital decision
The conclusion may support continued monitoring and maintenance, a targeted investigation, localized repair, a broader repair program, phased replacement, interior remediation, design work, temporary protection, warranty action, or a reserve allowance pending further study. It should identify the affected areas, known and suspected assemblies, current evidence, residual uncertainty, planning assumptions, and the next decision that would reduce it.
ASTM E2018 describes baseline PCAs as subject to uncertainty and allows the scope to be refined around the user’s objectives and risk tolerance. KOW’s due-diligence report should therefore separate visible condition, reported history, inferred relationships, recommended specialist work, and planning-level cost—so a history of leakage becomes an understandable exposure rather than a vague disclaimer or an unsupported replacement recommendation.
Primary sources
Sources and technical references.
Source review current as of September 1, 2026.