How many rulers does an attic need?

One for every 250 square feet, spread evenly and readable from the attic access, scaled in inches and installed R-value.

Is the rater required to take several weight samples?

No. The appendix says only one sample is taken, from the area that appears to have the least insulation.

QII for Attic Insulation: Rulers, Baffles, Hard Covers and Weight Checks

In a QII attic the installer prepares first with hard covers over drop ceilings and baffles at the eaves, then blows to uniform depth with a ruler for every 250 square feet. The ECC-Rater checks depth and takes one weight sample from the thinnest area. QII covers new homes and additions over 700 square feet, not a remodel top-up.

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Before the blower starts

Drop ceilings and interior wall cavities get hard covers or draft stops; if missing, they are completed first, or the drop area is filled level with the attic. Baffles go in at eaves and soffit vents so loose-fill cannot choke the net free ventilation area. Insulation stays away from combustion flues as the flue label directs, and runs to full depth under an HVAC platform, which is raised if needed.

While blowing

Attic rulers are installed and spread evenly, one for every 250 square feet, readable from the attic access and scaled in inches and installed R-value. Insulation goes under and beside cross-bracing and wiring, out to the wall top plate edge. Thickness must be uniform, every area meeting the manufacturer's minimum depth and weight. Recessed fixtures must be IC rated, airtight and covered; see recessed lights under attic insulation.

The weight and settling check

The paperwork states the minimum installed weight per square foot and the inches needed for the R-value; the installer certifies it was met and attaches the bag label or coverage chart.
The rater takes one sample from the area that looks thinnest, using ICAA Technical Bulletin 17 or 33, and records the weight on the Certificate of Verification.
For cellulose checked within 14 days, thickness must exceed the manufacturer's required thickness less a half inch for settling. After 14 days it must meet the settled thickness.

When the procedure does not apply

QII is required in new homes and additions over 700 square feet. It does not apply to additions of 700 square feet or less, and Section 150.2(b)1 lists no QII requirement for alterations. A remodel that only blows in insulation is checked for R-value and air sealing, as the attic remodel page explains.

The overview is on quality insulation installation, the wall side is on the wall inspection page, and the signed paper trail is on the contractor certificate page. A residential report sets the R-value.

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