In-depth guide to creating interior design spec sheets

Specs complement the visual core of an ever-evolving interior project. Designers scrutinize beyond the surface level of aesthetics and into the granular details of strength, function, cost and codes to deliver viable interior design spec sheets. From tangible to intangible details, find out how you can elevate human-centric interior spaces—on time and on spec.

Here are some of the most critical points to include in your interior design spec sheet:

Comprehensive interior design (CID)

Before we delve into the nitty-gritty of interior design spec sheets, let's scope out how the 2 components under CID cover different aspects of the interior environment.

Structural interior design (SID)

Enter building-related design elements. Any interior finish materials attached to the exterior shell and core, and which satisfy aesthetics, function, durability and safety fall under SID. Some elements include:

Wall finishes
Ceiling finishes
Floor coverings
Door frame finishes
Window frame finishes
Millwork materials
Built-in casework

Furniture, fixtures & equipment (FF&E)

Think of the moving parts around the furniture footprint of the interior spaces, with no permanent connection to the building structure or systems, such as:

Workstations
Seating and tables
Filing and storage
Cubicles and partitions
Artwork and accessories
Visual display items
Electronic equipment

To deliver successfully, we can't undermine how this differentiator serves as a precursor for the interior design spec sheets you create. Unless your client requests for CID, knowing the distinction between SID and FF&E will be a lifesaver when you align which specs work for new construction, renovation, adaptive reuse or tenant improvements. Doing so will:

Keep project stakeholders on the same page
Reduce rework
Shrink project timeline
Save more time & money

**Collaborative project delivery**

What if you can get early client buy-ins with your interior design spec sheets and eliminate VE from the start? In a nutshell, this is the whole premise of Source.
We've all heard the adage of how you specified down to the last detail, only for engineers or contractors to propose last-minute contract changes from best-value to low-cost material options. This used to be the case with linear design-bid-build, but not so much with the holistic approach of integrated project delivery (IPD).
Here's a great example: By working in tandem with structural engineers for SID, you can specify the wood species and shade variation of glued laminated timber (glulam), while they calculate the stress-rated weight per foot needed for beam spans. Taking iteration one step further is easier when you can reverse-engineer and inspire collaboration.

Specification types

When we relate how BIM and its hierarchical level of development (LOD) work with your interior design spec sheets, you get the gist of the concept. Same process goes for wielding which spec type will bolster the flow of your interior project from conceptual to technical details.

Performance specification

By default, performance specs can be considered open. Think of it as incentivizing contractor innovation: you give them more wiggle room to achieve the desired end results, rather than restricting through step-by-step methods.

2. Prescriptive specification

Control shifts for this spec type, and the onus lies on the interior designer to furnish detailed instructions down to the means of installation, sans the use of trade names. For complex projects which require higher quality control, deploy prescriptive specs which typically outline:

General: regulations, standards and contractor submittals
Products: performance, material and structural stipulations
Execution: installation methods and testing requirements

3. Proprietary specification

Proprietary specs demanding only one brand name or model type are closed spec types. Why use proprietary specs when scarcity drives up the total project cost? Reasons range from client's preference, consistency, or mission-critical product attributes with no suitable alternatives.

4. Reference standard

Take the cue from industry associations and leverage interior design spec sheet standards such as Construction Specifications Institute (CSI) MasterFormat, ASTM, LEED, MPI, and ANSI.

Spec types in action

See how these spec types work in sync using an entry door as a sample. In schematic design (SD) where you have brief project requirements, you can form an outline specification and use performance specs with thermal requirements such as:

Residential entry doors shall be solid core, insulated, seven panel doors.

But as you progress to detailed design stages, pulling up prescriptive, proprietary or hybrid spec types for your technical interior design spec sheets make more sense:

Residential entry doors shall be solid core, insulated, seven panel doors of type Sta-Tru Plus as manufactured by the Stanley Works of New Britain, CT. Factory-primed finish on all surfaces with minimum nominal dimensions of 3’-0” W by 6’-8” H.

Identify client needs

Capturing data at any design stage is paramount for interior project success, and it all starts with the client brief. If we see the spec structure in detail, specs put into words what visuals or drawings can't.

Over time, specs will evolve as you refine early customer criteria from digital or tactile mood boards and project binders, into high-level interior design spec sheets with technical attributes and commercial intelligence.

Residential vs. commercial interior design

Residential interiors hint at a more nuanced approach, where you can help clients put personalized touches on the style, materials and finishes of their interior spaces. Master spec sheets can be created, then allocated per room, area, function, finish schedules, SID and FF&E.

In commercial interiors, more foot traffic means stringent regulatory standards, with streamlined standardized approach and bespoke interior design spec sheets as the project calls for. Commercial projects stretch across education, health & wellness, office, hospitality, retail and workplace designs. In a global hotel chain alone, interior brand standards range from:

Luxury
Upscale
Mid-range
Basic

Verify, validate and test

Consider reverse-engineering competitor products to enhance values for your technical criteria in the design development (DD) stage. Deploy criteria parameters, such as:

Product performance
Legislative standards
Manufacturing
Verification tests
Sustainability
Maintenance

Take a residential sofa for a client office, for example. In layman's eyes, the sofa passes the aesthetic setpoints. Using your interior design expertise, you test for the smolder resistance in the furniture upholstery and filling, find it as a fire hazard and suggest a safer, commercial-grade option for your client. Some non-exhaustive codes to check aside from NFPA Fire Code:

ANSI/BIFMA X5: Standard for Office Furnishings
ASTM D2407: Slip Resistance Test
ASTM D4157-02: Textile Fabric Abrasion Resistance Test
ASHRAE 62-1989R: Indoor Air Quality
UBC 8-2: Textile Wall Coverings Test

As scope of work piles up, creating interior design spec sheets can be daunting. You need a flexible tool with filter tabs for specs as you switch back and forth between small to large-scale projects. Source is your solution.

Source and supply

Align technical specs with cost viability and lead times, and source the best-value products for your clients as you check physical material samples. With Source, you're all geared up for procurement no matter the phase you're in. Send the PO, manage the logistics, and install building products on spec.

Conclusion

Creating interior design spec sheets is a multifaceted, collaborative, agile and iterative process needing big picture vision and strong attention to details. Best to err on the right side of caution as you create aesthetically-pleasing spaces, and manage spec risks that may compromise safety or cater to legal stipulations.

Author

Karissa Austria | Architect, Construction Manager & Consultant