Guide · For the trade
Carpet specification: how to specify carpet so the mill, the installer and the inspector read the same page
A carpet specification names the product and the performance in a form that can be ordered, substituted against and inspected: mill, style and color; fiber and construction; pile height, face weight, density and width; backing, dye method and pattern repeat; fire, emissions and warranty; the pad, the installation method and the seam plan. For residential work it lives on the finish schedule; for commercial work it is Division 09 68 00 of the project manual. Everything on it comes off the mill's spec sheet.
This guide is for the designer or junior writing a carpet spec sheet for the first project where someone else will order, install or review it. It covers how to read a mill spec, the finish schedule line by line, what we need to turn the spec into an order, what the installer needs, and what to do when a contractor proposes an equal. The measurements each have a guide: pile height, face weight and density.
How to read a carpet spec sheet
Every mill publishes one per style, and they follow a loose standard. The header gives the style name and number, the mill and the country of manufacture. The construction block gives the method (tufted, Wilton, Axminster, hand-loomed), the pile type (cut, loop, cut and loop), the fiber and its percentage, the dye method, the gauge or pitch, the stitches or rows per inch, the pile height, the face weight in ounces per square yard, and sometimes the density. The dimensions block gives the roll width (12 ft, 13 ft 2 in or 15 ft), the pattern repeat and the match. The backing block names the primary and secondary backing and any attached cushion. The performance block gives the flammability class, smoke test, emissions certificate, static rating, use class or TARR rating, and warranties. A blank line means the mill did not test it.
The carpet spec sheet, line by line
| Line | What to write | Why it matters |
|---|---|---|
| Product | Mill, style name and number, color name and number | The order is placed from this line |
| Fiber and construction | "100 percent wool, Wilton, cut pile" or "solution-dyed nylon 6,6, tufted level loop" | Sets the performance class and what an equal must match |
| Pile height and face weight | Pile height in inches to the backing; face weight in oz/yd2; density if listed | The numbers an inspector or a substitution request will compare |
| Width and repeat | Roll width; pattern repeat width x length; match type (set, drop, quarter drop) | Decides the seam plan and the yardage |
| Backing | Primary and secondary backing; attached cushion; moisture barrier if required | Governs installation method and warranty |
| Fire and emissions | ASTM E648 class; ASTM E662 if commercial; CRI Green Label Plus or FloorScore; CA 01350 for California | Code and LEED reviewers look here first |
| Use and warranty | Use class or TARR rating; warranty types and terms | Matches the carpet to the traffic and protects the claim |
| Pad and installation | Pad by thickness, density and type; method (stretch-in, direct glue, double-stick); seam sealing; CRI 104 or 105 | Most failures and voided warranties start here |
What a residential spec needs that a commercial one does not
Residential specs are shorter: the finish schedule names the style and color, the pad, the areas by room with the yardage, and the installation method, and the sample card does the rest. The lines that get missed are the ones a client never sees: pile height on stairs (1/2 inch or less, dense), pad by construction (7/16 inch 8 lb rebond under cut pile; 1/4 to 3/8 inch dense under Berber, loop, Wilton and stair runners), pattern repeat, and seam direction. Commercial specs add the full performance block, the test reports, a maintenance section and a substitution clause; a hospitality or healthcare spec adds the brand standard on top, often stricter than code.
Basis of design, "or equal," and how to hold the spec
Most commercial specs name a basis-of-design product and allow equals, judged against the numbers you wrote: "wool Wilton, 40 oz" invites a 40 oz tufted polyester; "80/20 wool-nylon Wilton, 40 oz, 0.25 in pile, 8 pitch, 13 ft 2 in width, ASTM E648 Class I, 10-year commercial wear warranty, basis of design Prestige Mills [style]" does not. Require an 18 by 18 inch sample, the mill's spec sheet and the test reports with the submittal. Where the design depends on a color or pattern no other mill makes, say "no substitution" on that line. Dye lots, the quiet cause of most mismatches, have their own guide: dye lots.
What we need from you to turn the spec into an order
- The plan with the areas marked, or the room dimensions with doors, closets and stair counts. We check yardage and draw the seam diagram from it; see the carpet yardage guide and the seam diagram guide.
- The style and color, or the samples you want to decide between; samples for approved trade accounts ship from the mill within 24 hours.
- The pad and the installation method, or a request that we specify them.
- The install date and the ship-to address; made-to-order broadloom runs on a mill lead time we confirm with the quote.
- Any report the project needs attached: fire, emissions, warranty.
With that, a residential quote comes back in a day or two; a commercial package with submittals takes longer because the mill assembles the reports. Our installer network measures and installs anywhere in the United States, and the measure confirms the yardage before the order is placed; see the ordering broadloom guide.
What the installer needs from the spec
The installer works from the seam diagram, the pad spec, the method, the pattern repeat and the pile direction. Write the pile direction on the plan, mark where seams may and may not fall, state the transition strip at each edge, and name the standard, CRI 104 or 105, so power-stretching and seam sealing are not optional. On a pattern, state the match and whether it aligns across doorways; on stairs, waterfall or upholstered. The carpet installation checklist turns these into the walk-through.
Questions designers ask
What should a carpet specification include at minimum?
Mill, style and color number; fiber and construction; pile height, face weight and width; backing; fire class and emissions label where needed; pad and installation method; and the areas with yardage. On commercial work add the warranty terms, the use or TARR rating, the test reports and a substitution clause.
How do I read a carpet spec when the numbers are metric?
European and some Asian mills write pile height in millimeters, weight in grams per square meter and width in meters: 8 mm is 5/16 inch, 1,350 g/m2 is about 40 oz/yd2, and 4 m is 13 ft 2 in. Convert once on the schedule so the installer and the inspector see inches and ounces.
Is face weight or density the number to specify?
Both, with pile height. Face weight alone rewards tall, loose pile; density (face weight times 36 divided by pile height) rewards the tight, low pile that actually wears. Write all three.
How do I specify carpet for a hotel or a healthcare corridor?
Start with the brand or facility standard, then the code: ASTM E648 Class I, ASTM E662 smoke, CRI Green Label Plus, a dense low pile at 1/2 inch or less, direct glue or double-stick over a dense pad, and a commercial warranty with a TARR rating. The hotel carpet guide and the ADA carpet guide have the detail.
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