TagSound Insulation(120)

This technical memorandum from Harris Miller Miller & Hanson Inc. (HMMH), dated June 5, 2026, presents the results of interior sound insulation testing conducted in April 2026 for 30 homes near Seattle-Tacoma International Airport as part of the SEA Repair and Replacement Program. Acoustical engineers measured how well each room in these homes reduces outside aircraft noise, finding that only 4 of the 30 structures met the FAA's minimum threshold of 45 decibels of interior noise to qualify for sound insulation treatments. An additional 16 homes had at least one room exceeding that threshold, suggesting potential benefit from window and door upgrades, though current FAA policy does not require treatment based on individual room results alone.

Harris Miller Miller & Hanson Inc. (HMMH) conducted sound insulation testing at 30 homes near Seattle-Tacoma International Airport (SEA) in March 2026 to measure how much aircraft noise penetrates indoors. The study found that none of the 30 homes exceeded the FAA's 45-decibel interior noise threshold required to qualify for sound insulation treatments under current federal policy. However, nine homes had at least one individual room where interior noise levels surpassed 45 decibels, suggesting those specific rooms could benefit from upgraded windows or doors.

The Port of Seattle wrote to Des Moines Mayor Traci Buxton in December 2025 to explain its Sound Insulation Repair and Replacement Pilot Program, a $5 million initiative aimed at helping homeowners near Seattle-Tacoma International Airport whose aging sound insulation packages may no longer be performing adequately. The program focuses on homes that received insulation before 1993 and are located within the FAA-approved Noise Remedy Boundary, with eligibility determined by acoustic testing showing interior noise levels at or above 45 dB DNL. Of the 117 homes tested in the initial phase, five were found eligible, and the Port plans to expand outreach to an additional 209 homes in early 2026 while pursuing FAA grant funding that could cover up to 80% of design and construction costs.

The Port of Seattle responds to Burien's City Council regarding its Sound Insulation Repair and Replacement Pilot Program, explaining that the $5 million program targets homes insulated before 1993 that still measure at or above 45 dB DNL interior noise levels. Of 262 eligible homes in the highest noise zones tested so far, only 5 qualified for repairs, suggesting older insulation packages are still performing acoustically. The Port plans to expand testing to 209 additional homes in early 2026 and may access FAA grants covering up to 80% of design and construction costs.

The Sound Insulation Treatment Repair and Replacement Program Act, introduced by Rep. Adam Smith (WA-09), would allow the FAA to waive a rule that currently prevents federal Airport Improvement Program (AIP) funds from being used more than once on the same home. The bill addresses problems caused by poor-quality materials and faulty installations from early noise mitigation programs in the 1980s and 1990s, which left some homeowners dealing with mold, structural damage, and non-functioning insulation at their own expense. Airports would not be required to participate, but those that choose to could repair or replace defective sound insulation in homes still within the 65 DNL noise contour, provided an FAA-compliant noise auditor verifies the issues stem from improper installation or faulty materials rather than homeowner neglect.

This document is the National Defense Authorization Act for Fiscal Year 2026, a proposed federal law organizing defense spending and policy across eight divisions covering the Department of Defense, Military Construction, Department of Energy, and other areas. It outlines procurement authorizations for Army, Navy, and Air Force programs, including rules on aircraft, submarines, and unmanned vessels. This legislation does not address airport noise policy and is unrelated to Sea-Tac Airport or regional aviation noise regulations.

In September 2025, acoustical engineers tested 29 homes near Seattle-Tacoma International Airport to measure how much aircraft noise penetrates indoors. The study found that none of the homes exceeded the 45-decibel interior noise threshold required to qualify for federally funded soundproofing treatments, though 10 homes had at least one room above that level. The findings are part of SEA's Repair and Replacement Program, which evaluates whether previously soundproofed homes need updated windows and doors.