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How to Specify: Thermal Insulation

When specifying thermal insulation, be sure to consider the following: the building type, climate, structural and non-structural building systems, building code requirements and environmental concerns.

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This article is part of a series designed to help architects use Source, Architizer’s premier marketplace for building products. For more information on the platform, click here.

If you’re an architect, contractor or do-it-yourselfer, you probably already know how difficult and time-consuming it can be to research and select the building products that are right for your next project. Luckily, Architizer is here to help: Using our product catalog and Source, the new marketplace for building products, we’ve written a collection of “spec guides” on everything from marble to surface-mounted lighting. These will help you understand what factors to consider before making your next specification or purchase and help you to make the perfect product search on Source. Think of them as the ultimate specifier cheat sheet.

As the winter weather begins to take hold across the northern hemisphere, it seems like the perfect time to look at the art of specifying thermal insulation.

Thermal Insulation


Architizer: Building Products > Insulation & Waterproofing > Thermal Insulation
MasterFormat: 072100

Introduction + Tips

Thermal insulation consists of a single, continuous layer beneath the building envelope, which includes the lowest floor, exterior walls, ceiling and roof. No single thermal solution should be applied to an entire design, as each space offers unique parameters that the architect and designer must consider when developing floor plans, selecting materials and designing assemblies. At the beginning of a project, it can be challenging to identify the exact type of insulation that will possess the necessary thermal properties for your needs. Fortunately, Source is the perfect tool to help you specify this crucial element to meet exact requirements pertaining to energy efficiency.

With Source, the key is to provide as much information as you can. This will help the platform match you with ideal product manufacturers that offer exactly what you need. Don’t worry if you’re not sure exactly which type or material of insulation you need. Simply describe the climate and where you need the insulation, and the manufacturer can help out with the rest!

Example of thermal insulation within a cavity wall; via TheGreenAge


  • Building Type: Thermal insulation can be installed in a variety of spaces:
    • Residential
    • Commercial
    • Institutional
    • Industrial
  • New Construction or Retrofit: State whether your project is a new building or if it’s being retrofitted. If it’s a retrofit, to what extent are the structural systems going to be renovated? Thermal insulation is applied to walls and ceilings, and installation can be invasive.
  • Climate: What climate is the building located in? This is very important for determining the type of insulation you’ll need, so be sure to mention this to the manufacturer.
  • Layout and Plan: Describe the dimensions of the building and upload floor plans, if possible.
  • Structural Systems: The type of insulation used depends on the structural characteristics and accessibility of your building, so provide as much information about the existing or planned:
    • Building frames — wood or metal?
    • Wall
    • Floor systems
    • Ceiling systems
    • Attic or basement
  • Nonstructural Systems: Other factors of your project may require additional insulation, including:
    • HVAC systems
    • Electrical and plumbing ducts or piping
    • Windows and doors
  • Codes: Check local codes to determine the required insulation for different parts of your building.

Diagram showing rock wool insulation within a roof; via Archiproducts


  • Types: There are many types of insulation to choose from, which depend on what area needs to be insulated. If you’re unsure which to use for your project, your manufacturer can recommend an appropriate type.
    • Blankets – Comes in batts or rolls made of flexible material, such as fiberglass or rock wool, that can be trimmed to fit the size of a room.
    • Blown-in loose-fill – Loose fibers made of cellulose, fiberglass or rock wool that are blown to fill in empty wall cavities, irregularly shaped rooms or unfinished attic floors
    • Foam insulation – A spray made of polyisocyanurate or polyurethane; either open celled (better for slowing moisture transfer) or close celled (better for resisting heat transfer)
    • Rigid insulation – Boards or molded pipe coverings made from fibrous materials or plastic foams that are often used for foundations or as insulative wall sheathing
    • Reflective – Made from aluminum foils with many types of backings and typically used for roof rafters, floor joists or wall studs
  • R-value: The R-value is the most common way of differentiating between different types of insulation. It measures the rate that heat flows through a building material or building assembly depending on its thickness. The higher the R-value, the better the material is at slowing heat flow. Some values for common residential applications are listed below. However, as long as you can provide the climate and the location of the insulation within the building, the manufacturer can determine the best values for you.
    • Attics – vary from R30 – R60
    • Walls – vary from R13 – R27
    • Floors – vary from R13 – R30
  • Wall sheathing: An additional insulation layer that covers exterior frames, it provides extra protection from heat loss and adds a moisture barrier.
    • Wood – R0.6
    • Blackboard – R1.3
    • Foam – R2 – R3.5
  • Vapor Retarders: These prevent moisture from entering or exiting walls.
    • Materials – kraft paper, foil, plastics
    • Use – recommended between the floor and foundation of all buildings, but use in walls depends on the climate
  • Fire Hazards: Gypsum or interior paneling must cover vapor retarders, which are highly flammable.
  • Caulking: Don’t forget to mention any holes, penetrations or seams that may also require insulation.
  • Environmental: Many larger manufacturers have incorporated recycled material to reduce the use of raw materials. Don’t hesitate to specify any environmental requirements you might have.

Visit Architizer’s Product Catalog to check out the latest thermal insulation products.

Does your company manufacture thermal insulation? Click here to learn more about listing your product on Architizer.

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External Links

Green Building Advisor’s Overview on Insulation

DOE Fact Sheet: Insulation

NAIMA Insulation Knowledge Base

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