I've sat across the table from interior designers vetting our furniture for nine months now. The good ones don't ask about price first. They ask about construction first. And the questions they ask — the things they look for on a spec sheet before they're willing to specify a piece for a six- or seven-figure project — are not the questions a typical retail customer knows to ask.
This is the cheat sheet. What's actually on a furniture spec sheet, and what each line tells a designer about what they're really buying.
The Frame
The frame is the skeleton of every upholstered piece. It's the part you'll never see and the part that determines whether the sofa lasts five years or thirty.
Look for: kiln-dried hardwood. "Hardwood" alone is not enough. Green wood — wood that hasn't been dried — shrinks as it dries, and a frame built from green wood will develop gaps in its joints within 2-3 years. Kiln-dried hardwood is dried to a moisture content below 8%, which means it's stable. Industry standard for premium furniture is kiln-dried Appalachian hardwood (oak, maple, poplar). Look for that exact phrase.
Avoid: engineered wood, MDF, particleboard, plywood-only frames. These appear on cheap furniture as "wood" or "wood composite." They fail in humid environments, can't be reupholstered without falling apart, and have a useful life of 5-7 years.
Look for: doweled and corner-blocked joints. A high-end sofa frame has joints reinforced with hardwood dowels (small wooden pegs glued into matching holes) AND corner blocks (triangular reinforcements glued and screwed into every load-bearing corner). Mortise-and-tenon construction is even better. Cheap frames use staples and glue alone — these will loosen.
The Suspension
Under the cushions is a spring system that determines how the sofa supports your weight over time.
Eight-way hand-tied: Coil springs tied by hand in eight directions to create an interconnected suspension. Most expensive, most labor-intensive, longest-lasting. Used in heirloom-quality furniture. We use a proprietary modern equivalent that delivers the same performance — see our seat suspension explainer for details.
Sinuous (S-spring): Steel coils shaped like waves, attached to the frame at both ends. Lower cost, less plush, slight tendency to sag at the center over decades. Acceptable on mid-tier furniture. Not acceptable on a $4,000+ sofa.
Webbing only: Elastic or jute straps with no metal springs. Found on certain mid-century reproductions and budget furniture. Comfortable when new, sags within 3-5 years.
The Cushion
Cushion construction is where most spec sheets get vague. Push for specifics.
Ask for foam density. Foam is rated by density in pounds per cubic foot. Anything below 1.8 lb is throw-pillow grade and will compress permanently within months. Quality seat cushions use 2.0–2.5 lb density foam wrapped in feather, down, or polyester fiber. Top-tier sofas use high-resiliency foam core with down-wrapped over-stuffing — the cushion that "fluffs back" after you stand up.
"Down-wrapped" vs. "down-blend" vs. "down." Down-wrapped means there's a foam core surrounded by down. Down-blend means a percentage of down mixed with synthetic fill. Pure-down cushions look beautiful but require constant fluffing — most clients hate them within six months. Down-wrapped is the right answer for most projects.
The Fabric
The fabric label is its own document, and we've covered the details in our fabric label guide. The two numbers to find on the spec sheet:
Double rub count. The Wyzenbeek abrasion test. 15,000 double rubs is residential minimum. 30,000 is residential heavy-use. 50,000+ is contract grade. Any spec sheet that doesn't list this number is hiding something.
Fiber content. Down to the percentage. "100% performance" is marketing — what is the actual fiber? Solution-dyed acrylic? Polyester with a topical treatment? Real performance fabrics like Crypton bond the stain resistance into the fiber itself, not the surface.
The Joinery (For Wood and Stone Pieces)
For tables, chairs without upholstery, and casegoods — the joinery is the entire spec.
Look for: solid wood with mortise-and-tenon, dowel, or dovetail joints.
Avoid: butt joints, biscuit-only joints, or pocket-screw joints on visible surfaces. These are fast-build joinery used in mass production. They hold short-term but loosen with use.
For stone pieces: ask whether the stone is solid or veneered over a substrate. Solid stone (like the slabs we use on the Socle Grand) is structural. Veneered stone is a 1/4-inch facing glued to MDF or particleboard. Both have their place, but they should be priced very differently.
What's Not on the Spec Sheet
Two things never appear on furniture spec sheets and matter enormously:
Where the frame is built. A sofa whose fabric is "Italian" but whose frame is built in a Vietnamese factory under no quality control will fail in five years regardless of the fabric. Ask where the frame is constructed. We build ours in our factory partner in North Carolina.
Reupholstery cost as a percentage of new. A well-made sofa can be reupholstered three times over its lifetime, extending it to 30+ years. A poorly made sofa cannot — the frame won't survive the process. If you can't reupholster a piece for 30-40% of the new cost, it isn't built to last.
The Designer's Cheat Sheet, Reduced
Six questions to ask a manufacturer before specifying any upholstered piece:
- Is the frame kiln-dried hardwood with doweled and corner-blocked joints?
- What is the suspension system (and avoid "webbing only")?
- What is the foam density and cushion construction?
- What is the double-rub count of the standard fabric?
- Where is the frame built, and where is the upholstery applied?
- Can this piece be reupholstered, and at what approximate cost?
If a manufacturer can't answer all six in writing, they're either hiding something or not paying attention to the right details. Our trade program publishes complete spec sheets on every piece by default — that's the standard.
For the trade application: thepatternroom.co/trade. For specific spec questions on a project, write to trade@thepatternroom.co.
