R-value measures the thermal resistance of material. A higher R-value represents greater insulating effectiveness, resisting heat transfer through wall assemblies.

How is insulation batt count calculated?

Divide total wall or ceiling area by the square footage coverage of a single batt (e.g. 15 in × 93 in batt covers 9.69 sq ft). Round up to the nearest whole batt.

What R-value is recommended for residential attics?

IECC standards recommend R-38 to R-60 for northern cold climates (US Zones 5-8), and R-30 to R-38 for southern hot climates (US Zones 1-3).

What is the standard batt size for 16-inch stud spacing?

Standard batts for 16-inch on center (o.c.) framing are manufactured at 15 inches wide to slide snugly between 2x4 or 2x6 wooden studs.

How does cellulose insulation compare to fiberglass?

Cellulose (R-3.7/inch) features slightly higher thermal resistance per unit depth than standard fiberglass batts (R-3.14/inch) and fills voids more uniformly.

What insulation R-value does SBC 601 require for GCC roofs?

The Saudi Building Code SBC 601 establishes roof R-value requirements of approximately R-30 (U-value 0.188 W/m²K) to limit solar thermal gains in desert climates.

What is the difference between faced and unfaced batts?

Faced insulation includes a kraft paper backing acting as a vapor barrier. Unfaced insulation has no backing, used primarily for interior sound dampening or adding over existing layers.

How is waste factor calculated for insulation projects?

A standard 5% to 10% waste buffer is added to cover scrap pieces cut to fit narrow framing cavities and outlet boxes.

Is vapor barrier required in hot, humid climates?

No. In hot, humid climates, vapor barriers should be placed on the exterior face of structural framing to prevent exterior humidity from condensing inside drywall surfaces.

What is mineral wool?

Mineral wool (rockwool) is made from molten slag and basalt rock. It offers high fire ratings (melting point > 2,000°F) and excellent acoustic dampening.

Inputs

Batt Insulation Calculator (R-Value & Rolls)

🧱 Wall Assembly & R-Value Cross-Section

Calculation Results

Required estimates based on your parameters:

Required Batts/Rolls

34 batts

Based on selected dimensions

Required Net Area

320.00 sq ft

Target R-30: 9.5" Fiberglass

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Select	Material Item	Quantity	Safety Margin / Notes

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Material / Labor Category	Quantity	Estimated Cost Range	Source & Benchmark Info

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Sources & Governing Codes

IRC 2021 Section N1102 Building Thermal Envelope Code: IRC 2021 Section N1102 Building Thermal Envelope Code View Standard
DOE Building Envelope & Residential Insulation Guidelines: DOE Building Envelope & Residential Insulation Guidelines View Standard
ASHRAE Standard 90.1 Energy Standard for Buildings: ASHRAE Standard 90.1 Energy Standard for Buildings View Standard

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Batt Insulation Calculator (R-Value & Rolls)

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Batt Insulation Calculator (R-Value & Rolls)

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📋 Job Bill of Materials (BOM)

💰 Project Cost Estimator

📁 Save My Project

Saved Estimations

📄 Email Me My Results

Sources & Governing Codes

Roofing & Framing

Design & Finishes

Mechanical & Safety

Contracts & Controls

Trade Hubs

Resources

Company