Takeoff & Estimating — Roofing, Envelope & Finishes

Blanket Insulation

Flexible batts or rolls of fibrous insulation, priced by square foot at a given R-value.

Quick Answer

Blanket insulation is flexible insulation supplied as continuous rolls or pre-cut batts, usually mineral fiber such as fiberglass or rock wool, that fits between studs, joists or rafters. Estimators measure it in square feet of surface covered, at the R-value and thickness the specification calls for, and add waste.

The Full Picture

Blanket insulation is one of the main insulation forms. The DOE guide to home insulation lists blankets, including batts and rolls, alongside loose fill, foamed-in-place, rigid and reflective types, and describes them as continuous rolls or pre-cut panels called batts. The federal rule on insulation labeling, 16 CFR 460.2, defines insulation broadly as any material mainly used to slow heat flow, and says it may be fibrous and may come in flexible form. On commercial jobs the product is most often fiberglass or mineral wool, and it may be unfaced or have a paper, foil or vinyl facing.

Install variants matter to price. Batts or rolls sit in wall, floor, ceiling and roof framing cavities and are sized to the common framing spacings, so the cavity depth and the spacing determine which product fits. Faced products carry a stapling flange or a vapor-control facing, and unfaced products friction-fit. Thicker products for attics and cathedral ceilings cost more per square foot. Sound batts in partitions, and batts behind exterior sheathing in a metal-stud wall, are separate line items because the product, thickness and labor differ.

The unit is square feet of surface to be insulated, taken from wall elevations, floor and roof plans, and building sections, with the thickness or R-value carried in the item description. Estimators often convert square feet to packages using the manufacturer's coverage per bag or roll, since coverage varies by product and thickness. Linear feet matter mainly for narrow strips, such as rim joists or perimeter edges. Squares (100 SF) are less typical for batts than for roofing, but some contractors still quote that way.

Pricing mistakes are usually about scope, not arithmetic. Walls are measured gross and then reduced for openings, but a lot of insulation scope is hidden: rim and band joists, spaces behind tubs and at corners, the gap above a ceiling, and fire-rated or sound-rated assemblies that call for a specific product. Note also that R-value is a labeled performance figure, not a thickness: the FTC rule on R-value per inch claims requires that where the R-value of a product drops with greater thickness, it be disclosed, so the specified R-value is what must be priced. Division 07 holds thermal insulation, and the architectural sheets, wall-type schedules and energy notes tell you which R-value goes where.

Real Examples

→Worked takeoff: wall batts: A building has 120 LF of exterior wall at 9 ft high, so gross wall area is 120 x 9 = 1,080 SF. The openings are 6 windows at 3 x 5 ft (15 SF each, 90 SF) and 2 doors at 3 x 7 ft (21 SF each, 42 SF), so deductions total 132 SF. Net wall area is 1,080 - 132 = 948 SF. Adding an assumed 5% for waste and cutting gives 948 x 1.05 = 995.4, which rounds to 996 SF of R-13 batts, to be converted to bags at the manufacturer's coverage.

→Worked takeoff: ceiling blanket: An attic floor is 40 ft x 30 ft = 1,200 SF. A 4 x 8 ft chase (32 SF) is left uninsulated, so the net area is 1,200 - 32 = 1,168 SF. That quantity is carried at the R-value on the drawings, and the estimator checks the thickness against the joist depth before pricing.

→Scope check: A wall-type schedule shows batts in the exterior stud walls and acoustic batts in interior partitions. The estimator lists them as two items with different products, because the area, thickness and unit price differ for each.

Common Misconceptions

People assume: Insulation is priced by thickness.

Actually: It is specified and priced by R-value and material. Federal labeling rules say a product's R-value per inch can drop as it gets thicker, so thickness alone does not tell you the performance.

People assume: Net wall area is all the insulation scope there is.

Actually: Rim joists, band areas, soffit and furrdown spaces, and rated or sound partitions often carry insulation that never appears in a simple wall area. Check the sections and wall types, not just the elevations.

Does MeltPlan Solve This?

Partially — adjacent

Wall, floor and ceiling areas for insulation come off the plans, and MeltPlan's takeoff service pulls those areas with AI and has US-based experienced estimators review and adjust them. Which product, facing and R-value to carry, and what waste to add, stay with your estimating team.

Get insulation areas measured from your plans →

Frequently Asked Questions

What is blanket insulation?

It is flexible insulation made as continuous rolls or pre-cut batts, usually fiberglass or mineral wool, that fits between framing members. The DOE guide calls it perhaps the most common type used in US homes.

How is blanket insulation measured for an estimate?

In square feet of surface covered, taken from elevations, floor and roof plans and sections, with the R-value in the description. Estimators then convert to bags or rolls using the manufacturer's coverage and add waste.

What is the difference between batts and rolls?

Rolls are continuous lengths cut to fit, and batts are pre-cut panels. Both are blanket insulation. Rolls suit long uniform runs, batts suit standard cavities, and both are measured in the same way.

Should faced and unfaced batts be priced separately?

Yes. The facing changes the product price and the way it is installed, and a vapor-control facing is a design decision that should be confirmed in the specification.