Dryer Vent Cleaning & Inspection in Menlo Park, CA

## Severe Lint Accumulation and Attic Contamination Found in Menlo Park Home Upon arrival at this Menlo Park residence, our technician identified a dryer exhaust system in urgent need of service. The exterior vent opening, accessible from a deck, showed a dark interior cavity consistent with significant lint accumulation deep within the duct run. More critically, inspection of the attic space revealed a heavy blanket of lint covering the floor and surfaces throughout, a clear sign that the dryer exhaust system had been exhausting lint into the attic rather than to the exterior. Per IRC M1502.2, dryer exhaust must be conveyed independently and entirely to the outdoors. Venting into an attic or any concealed space is a code violation and a serious fire hazard, since lint is highly combustible and can accumulate against electrical wiring and structural members. ## Urgent Fire Risk: Lint Accumulation Classified as Severe The duct interior showed greater than 50% occlusion by compacted lint, meeting the criteria for a severe lint accumulation finding (issue code: LINT_BUILDUP_SEVERE). According to the U.S. Fire Administration, lint buildup is the leading factor in approximately 2,900 residential dryer fires each year. Back-pressure from a duct this restricted causes exhaust temperatures to climb well above safe limits at the dryer connection, and drying times extend to two or more cycles as the dryer struggles to push air through the blockage. All lint was successfully removed using an air whip tool, working entirely from the exterior of the property, a method that minimizes disruption inside the home while ensuring thorough cleaning along the full duct run. ## Missing Backdraft Damper Noted at Exterior Termination The exterior vent opening showed no visible backdraft damper or flapper. Under IRC M1502.3, all dryer exhaust duct terminations must be equipped with a backdraft damper that opens freely under dryer airflow and closes by gravity when the dryer is off. Without this component, outside air, rain, insects, and pests can freely enter the duct when the dryer is not running. The absence of a damper also contributed to the conditions that allowed this vent to become so heavily soiled. A compliant replacement cap with an integrated gravity damper is recommended to bring this termination into conformance with M1502.3. ## Outcome and Recommended Next Steps The dryer exhaust duct was fully cleaned from the exterior using an air whip and motorized brush equipment, with all lint successfully extracted from the system. The Menlo Park homeowner should follow up on the missing backdraft damper at the exterior termination and consult with a qualified contractor regarding the lint that escaped into the attic space, as that material poses an ongoing fire risk until removed. Annual professional dryer vent inspection is recommended going forward, consistent with NFPA guidance, to prevent lint from reaching critical accumulation levels again. Scheduling service once per year is the most effective way to keep this system operating safely and efficiently.