Interior Design Specifications for Contractors
Detailed interior design specs are essential for streamlining projects, avoiding costly rework and ensuring field execution aligns with design intent. This guide helps contractors confidently interpret and implement interior design materials and specifications with practical insights on documentation, coordination and compliance. Use it to deliver quality results, reduce project risks and keep installations on track from submittal to final inspection.
What Contractors Need From an Interior Design Specification Sheet
A comprehensive and well-organized specification sheet is your best defense against change orders and project delays. When you can access all selections and requirements up front, you can compress timelines and improve quality and compliance. A full specification sheet should include the following information.
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Division 08 door, frame and hardware selections: An interior design spec sheet should identify all door types, frame materials and hardware sets. Contractors rely on precise product numbers, manufacturer details and finish options to ensure correct ordering and installation. Ambiguity here can lead to costly mistakes or delays.
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Finish schedules: A finish schedule provides a room-by-room or opening-by-opening breakdown of finishes, colors and materials. This information allows contractors to coordinate with painters, flooring installers and other tradespeople, ensuring a cohesive look and preventing mismatches.
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Performance ratings: Specifications must include required fire ratings and acoustic ratings for each door assembly. These details are vital for code compliance and for meeting the project’s functional requirements.
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Americans with Disabilities Act requirements: Contractors need direction on accessibility standards, including door widths, hardware types, mounting heights and maneuvering clearances. Well-documented ADA requirements avoid rework and ensure the finished space is accessible to everyone.
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Shop drawings and submittals: A spec sheet should outline the process and expectations for shop drawings and submittals, including timelines, required details and approval procedures, enabling contractors to plan and avoid bottlenecks.
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Coordination notes: Effective spec sheets highlight areas that need coordination with other trades — such as electrical for access control or wall types for frame anchoring. These notes help contractors anticipate challenges and streamline on-site collaboration.
A Guide to the Essentials for Internal Doors
Internal door assemblies are unique systems, and each element, from the hardware to the frame, must work together to ensure proper function and code compliance. The CSI MasterFormat system is the industry standard, with Division 08 dedicated to doors, frames and hardware. Contractors who coordinate these details will enjoy smoother projects.
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Section 08 1400 covers all the details about the doors, including their materials, thicknesses, fire ratings and finishes. Section 08 1100 and 08 1200 describe the frames that hold the doors, and section 08 7100 lists all the parts that make the door work, such as handles, locks, hinges and closers. This section also includes hardware schedules that show which hardware goes on which door.
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Before installation, contractors must provide detailed information.
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Cut sheets: These refer to the manufacturer’s product information for each door, frame and hardware item.
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Labels: Certification labels for fire-rated or sound-rated doors and frames are essential.
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Shop drawings: Contractors must submit detailed drawings showing how doors, frames and hardware fit together, including sizes and installation details.
If the information in these sections does not match, like a door that is too thick for its frame or hardware that does not fit the door, contractors must send a request for information to the design team. RFIs ask for clarification or corrections, which can slow down the project.
Door Type, Construction and Core
Specifying the correct construction, core and duty level ensures the door meets performance expectations, passes inspections and minimizes callbacks. The Window & Door Manufacturers Association outlines standards for interior wood flush doors. These doors typically have a solid or composite core, and the core type directly impacts durability, weight and performance. For example, particleboard is suitable for light-duty interiors, like offices, while staved lumber is ideal for high-traffic areas.
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ANSI/WDMA I.S.1A defines duty levels to match door construction to the demands of the space.
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Standard duty: Light use, such as private offices or closets
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Heavy duty: Moderate to high use, such as classrooms or hotel rooms
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Extra heavy-duty: High-traffic areas, such as corridors in schools or hospitals
Most interior wood flush doors are specified at 1 and 3/4 inches thick, though 1 and 3/8 inches is sometimes suitable for lighter-duty applications. Per ANSI/WDMA I.S.1A, allowable tolerances for width, height and thickness are typically plus or minus 1/16 inch. The standard warp limit is 1/4 inch in any 3-by-7 section of the door, measured as a deviation from a straight line.
Fire Ratings and Labeling Requirements
Fire-rated doors are a critical part of building safety, and their specifications adhere to tight regulations. Contractors must understand the requirements for fire ratings, labeling and installation to ensure code compliance and occupant protection.
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Fire doors receive ratings based on their ability to withstand fire, typically measured in 20, 45, 60, 90 or 180-minute increments. The required rating depends on the location in the building and the wall rating. Most modern codes also require testing for positive pressure, which involves simulating real fire conditions where hot gases push against the door.
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The National Fire Protection Association created NFPA 80 to regulate the installation and maintenance of door assemblies. NFPA 80 also requires fire doors, frames and hardware to include a label highlighting that the component has undergone testing from an acceptable organization. These labels must include component ratings, the certification agency, manufacturer name and fire test standard designation.
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Field modifications, such as cutting for hardware or adding holes, are strictly off-limits unless the manufacturer and listing agency specifically permit it. Unauthorized modifications can void the fire label and the assembly’s rating.
Accessibility Widths, Maneuvering and Hardware Heights
Ensuring doors are accessible is a prerequisite of any interior project. ADA compliance requirements outline specific requirements for door openings, clearances and hardware to make sure everyone can use doors safely and easily, regardless of their abilities.
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Clear width: The minimum clear opening for a swinging door is 32 inches. If the doorway is deeper than 24 inches, the clear width must be at least 36 inches.
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Projection limits: Nothing can stick out into the clear width below 34 inches above the floor. Between 34 and 80 inches high, projections, such as door handles or hardware, can extend up to 4 inches into the clear width.
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Vertical clearance: Doorways must have a minimum clear height of 80 inches free from protrusions.
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Maneuvering clearances: There must be enough clear floor space on both sides of the door for a wheelchair to approach and operate the door. The required space depends on the door’s swing and approach direction, but typically ranges from 18 to 60 inches in depth and 42 to 60 inches in width.
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Hardware heights: Door handles, pulls, latches, locks and other operable parts must be 34 to 48 inches above the finished floor. Users must be able to operate hardware with one hand without needing to twist their wrist or grasp tightly.
Talk to a Door Expert for Spec Validation
When you need high-quality doors to meet industry standards and compliance regulations, trust our team at DoorStop to help you find the ideal solution. With us, you can customize each aspect of the doors you purchase, ensuring you can meet specifications. Contact us to request product guidance for your custom doors.