Material Selection & Specifications

Knowing what materials exist is only half the equation — knowing how to select the right material for a specific application and how to communicate that selection through specifications is equally important. This lesson covers the specification process, material submittals, sustainability considerations, and the CSI MasterFormat system that organizes construction specifications.

Construction specifications are written documents that describe the quality, type, and standards of materials and workmanship required for a project. While drawings show what to build and where, specifications describe how to build it and with what.

Specifications answer questions like:

• What type of concrete should be used for the foundation? (Strength, air content, admixtures, curing method)
• What grade and coating must the structural steel have?
• What fire rating is required for the interior partitions?
• What manufacturer and model of window is acceptable?

The Construction Specifications Institute (CSI) developed MasterFormat — a standardized numbering system for organizing specifications. The current edition has 50 divisions:

Procurement and Contracting Requirements (Division 00)

• Bidding requirements, contract forms, conditions of the contract

Specifications (Divisions 01-49)

Key divisions for materials:

Each division is further broken into sections with six-digit numbers. For example:

• 03 30 00: Cast-in-Place Concrete
• 05 12 00: Structural Steel Framing
• 07 92 00: Joint Sealants
• 09 29 00: Gypsum Board

Prescriptive Specifications

Tell the contractor exactly what to use and how to install it. Leave no room for interpretation.

Example: "Install 5/8-inch Type X gypsum board, manufactured by Georgia-Pacific (ToughRock Fireguard), attached to steel studs with 1-inch Type S drywall screws at 12 inches on center."

• Pros: Clear, easy to verify compliance.
• Cons: Places all responsibility on the designer; limits competition; may exclude equivalent products.

Performance Specifications

Describe the required outcome (performance) without specifying the exact product or method.

Example: "Provide a partition assembly with a minimum STC rating of 55 and a 1-hour fire-resistance rating, tested in accordance with ASTM E119."

• Pros: Encourages innovation; allows competition; places performance responsibility on the contractor.
• Cons: Harder to verify compliance; may require testing and documentation.

Proprietary Specifications

Name a specific manufacturer and product.

Example: "Provide Trespa Meteon High Pressure Laminate panels, color NW09 Mountain Grey, 8mm thickness."

• Pros: The designer gets exactly what they want; quality is known.
• Cons: Limits competition; may be more expensive; manufacturer may not be available.

"Or Equal" Specifications

Name a specific product but allow substitutions that are "equal" in quality and performance.

Example: "Provide Marvin Signature Ultimate Double Hung Window, or approved equal."

• Pros: Establishes a standard while allowing competition.
• Cons: "Equal" is subjective — leads to disputes about what qualifies.

Submittals are documents provided by the contractor to the architect/engineer for review and approval before materials are fabricated or installed. They verify that the contractor is providing materials that comply with the specifications.

Types of submittals:

• Product data: Manufacturer's literature, cut sheets, technical data, and catalog pages.
• Shop drawings: Detailed fabrication drawings prepared by the contractor or supplier (e.g., structural steel shop drawings, curtain wall shop drawings).
• Samples: Physical samples of materials (brick, stone, tile, paint colors, carpet).
• Test reports: Documentation of testing (concrete strength, steel mill certificates, fire test reports).
• Certificates: Manufacturer's certifications of compliance with standards.

Review process:

1. Contractor submits to architect/engineer.
2. Architect/engineer reviews for compliance with design intent and specifications.
3. Response stamps: Approved, Approved as Noted, Revise and Resubmit, Rejected.
4. Contractor proceeds only with approved or approved-as-noted submittals.

When a contractor wants to use a product different from what is specified (typically for cost or availability reasons), they submit a substitution request. The request must demonstrate that the proposed product meets or exceeds the specified product's performance, quality, and appearance. The architect/engineer decides whether to accept the substitution.

Material selection increasingly considers environmental impact:

• Embodied carbon: The total carbon emissions associated with manufacturing, transporting, and installing a material. Concrete and steel are the largest contributors to embodied carbon in buildings. Reducing cement content (using SCMs), using recycled steel, and specifying local materials all reduce embodied carbon.
• Recycled content: The percentage of recycled material in a product. Steel has the highest recycled content of any structural material (~93% for structural shapes, ~70% overall). Concrete can incorporate recycled aggregates and SCMs (fly ash, slag).
• Environmental Product Declarations (EPDs): Third-party verified reports that quantify a product's environmental impact across its lifecycle — raw materials, manufacturing, transportation, use, and end of life. EPDs are becoming increasingly important for LEED and other green building certifications.
• Regional materials: Materials sourced within a defined radius of the project (typically 500 miles) reduce transportation-related emissions and support local economies.
• Durability and lifecycle cost: A material that lasts 50 years with minimal maintenance may have a higher upfront cost but lower lifecycle cost (and environmental impact) than a cheaper material that requires frequent replacement.
• End of life: Can the material be recycled, reused, or must it go to a landfill? Steel is fully recyclable. Concrete can be crushed and reused as aggregate. Wood can be reclaimed. Most plastics are difficult to recycle in construction applications.