Tag tables proposal to require on‑site density testing for blown‑in blanket insulation; proponents to redraft language

The residential energy code tag tabled a proposal to add an explicit requirement for on‑site density verification of blown‑in blanket (dense‑pack) wall insulation, asking the proponent and volunteers to rewrite the text so it clearly prescribes sampling method and reporting.

Rick Blumenthal, the proponent, said the current code lacks a clear method to verify density for dense‑pack wall systems and recommended a simple weigh‑and‑record approach. “The only way to verify the density and that's the only way to do it,” Blumenthal said. He described the method as taking a small cavity sample, sealing it in a bag, and weighing it on a scale to confirm pounds per cubic foot.

Several participants noted the intent but flagged implementation issues. Tom Balderson said density testing “takes more than a few minutes,” citing the need for a scale, measured sample size and calculation of cavity volume. He asked whether testing would be required one place or multiple places in a dwelling and raised training needs for inspectors. Patrick Hanks and others said they understood the intent but worried the cumulative time could be significant at scale: Hanks observed that “even if it only takes 20 minutes per weighing, you have to do that 3 times per house. If you have a 50 unit development, you're adding 50 hours of extra time.”

Blumenthal proposed a pragmatic sampling frequency — roughly one test per 500–600 square feet of insulated wall area — and said installers would perform the sampling and document the results rather than waiting for building inspectors. “You measure as you go,” he told the tag, describing three checks on a typical house as sufficient and saying the installer should record sample weights and dates on the job record.

The tag’s technical commenters recommended bringing the proposal into alignment with existing code sections that reference installed density (notably section 303.1.x was discussed) rather than adding new, duplicate language without clear test standards. Several members suggested revising the proposal to add explicit test frequency, sampling protocol and a short installer reporting form for the inspection record.

After discussion the tag voted to table the proposal and asked Blumenthal to work with Greg Davenport and Tom Balderson on redrafting the text. The motion to table carried; staff will post revised code language for the tag to review at a future meeting.

No formal code change was adopted at this meeting; the item will return after the proponent supplies clearer code text and test/recording details. The tag requested that any revised proposal specify whether testing is installer‑performed with documentation provided at inspection or requires an inspector‑witnessed test, and to quantify sampling frequency per square footage or per unit so jurisdictions can estimate labor impact.