Section 12 24 13 is the MasterFormat number for Roller Window Shades, the specification section that says which shades the architect wants, how they are sized, what extra work comes with them and who connects the motors. Read it before you count, because a few of its paragraphs add shades, labor and cost that never appear on the drawings: spare shades, a mock-up, motor wiring and training, a warranty longer than your manufacturer's standard, and a field-measure requirement that changes your schedule. This post walks through the three parts of a typical 12 24 13 section, the clauses that change quantity or price, and how to read the spec alongside the plans.
Where 12 24 13 sits in a bid set
MasterFormat is the numbering system the Construction Specifications Institute maintains for organizing project specifications. Window coverings live in Division 12, Furnishings, and 12 24 13 is the roller shade section. ARCAT lists it as "12 24 13 - Roller Window Shades" with the manufacturers that publish guide specs for it.
Architects usually start from a master spec or a manufacturer's guide spec and edit it; the OGS master opens with an instruction to revise it "by deleting and inserting text to meet Project-specific requirements." Three free public examples show what you will see on real jobs:
- The New York State OGS MasterSpec 2024 section 12 24 13, a state agency's master with the editor's notes left in.
- Manufacturer guide specs on ARCAT, such as MechoShade's 12 24 13 and SWFcontract's 12 24 13 for manual roller shades.
- The federal UFGS 12 24 13 Roller Window Shades guide specification on WBDG, used on Department of Defense work.
On a live bid, only the project manual's version counts.
Part 1, General: scope, submittals and the hidden quantities
Part 1 sets the rules around the product. In the OGS master it covers the summary (what the section includes), allowances, submittals, quality assurance, delivery and field conditions. The paragraphs to slow down on:
- Section includes: The OGS master lists manual and motor-operated shades, single or double rollers, and shades for skylights. Skylight shades are a different product with their own price, so note if they are in.
- Related sections: The OGS editor's notes point wood blocking to Section 06 10 00 or 06 10 53 and perimeter sealant at light-blocking accessories to 07 92 00. That is work someone else provides.
- Allowances: The OGS master has a paragraph that reads "Roller shades are part of [Window-Covering Allowance]." When it is kept, the owner has carried a cash amount and your number may only need to fit inside it.
- Submittals: Product data, samples, shop drawings, a window treatment schedule and, for motorized shades, wiring diagrams for power, signal and control.
- Extra materials, quality assurance (installer qualifications and any mock-up), field conditions and warranty: each covered in the clause list below.
Part 2, Products: what you are pricing
Part 2 defines the product. Check each piece against the manufacturer you plan to quote.
Start with manufacturers and substitutions. The SWFcontract guide spec gives the architect two choices: "Substitutions: Not permitted," or requests "considered in accordance with provisions of Section 01 60 00 - Product Requirements." If the first one survives and you sell a different brand, you either price the named product or get prior approval under Division 01 before bid day.
Fabric comes next: openness factor, color, flame test and roll width. The SWFcontract spec lists fabrics with roll widths up to 126 inches (several at 98 inches), and openness factors from 1 to 14 percent. Roll width matters because a shade wider than the roll has to be railroaded (turned sideways), which can mean seams. The OGS master tells the fabricator to railroad "where material roll width is less than the required width of shadeband" and to add battens and seams as required.
Unit sizes are easy to skim past. The OGS master sizes an inside-mount shade at the jamb-to-jamb dimension "less 1/4 inch per side or 1/2-inch total, plus or minus 1/8 inch," and the length at head to sill less 1/4 inch. Your manufacturer's order form may ask for the opening size and take its own deductions instead. Know which rule you are under before anyone writes an order, or the shade gets deducted twice.
Accessories and operation round out the part. Fascia or headbox, side and sill channels for light-blocking shades, chain type, crank or motor, and the motor's electrical characteristics. The OGS master offers 110-V ac, 220-V ac, 24-V dc, 12-V dc and solar-powered dc, which changes who has to bring what power to the head of each shade.
Part 3, Execution: who connects, where shades go, and training
Part 3 is short, but it decides who connects the motors and where shades go. In the OGS master:
- Examination includes "locations of connections to building electrical system" when motors are retained.
- Opaque shadebands sit no closer than 2 inches to the inside face of the glass, with clearance for window hardware.
- "Electrical Connections: Connect motor-operated roller shades to building electrical system." If Division 26 does not pick that up, it may land on you.
- "Roller Shade Locations" has three options: at exterior windows, as indicated in a window-covering schedule, or as indicated on the drawings. Which one survived decides your count.
- Demonstration: training the owner's maintenance staff on motor-operated shades.
The clauses that change quantity or price
This is the short list to pull into your bid notes every time:
| Clause | Where it usually sits | What it can add |
|---|---|---|
| Extra materials (spares) | Part 1, submittals or closeout | Whole shades: the OGS text asks for 5 percent of each size, color and fabric, "but no fewer than two units" |
| Mock-up | Part 1, quality assurance | A shade built early, possibly rebuilt; SWFcontract's text allows it to stay in the work if undisturbed |
| Motorization | Part 2 and Part 3 | Motors, controls, wiring diagrams, connection to building power, training |
| Warranty | Part 1 | Years beyond the manufacturer's standard you may have to back |
| Field measurements | Part 1, field conditions | A return trip and a fabrication schedule tied to the GC's progress |
| Substitutions | Part 2 or Division 01 | A different price if your brand is not allowed |
| Railroading, seams, battens | Part 2, fabrication | Seamed shades or a fabric change on wide openings |
| Light-blocking accessories | Part 2 | Side channels, sill channels, headboxes, measured by the linear foot |
Spare shades, read literally
SWFcontract's version reads "5 percent of quantity installed for each size and color material indicated," with an optional minimum of "no fewer than two units." Read literally on a job with 14 shades in 3 sizes, 5 percent of each size rounds to less than one shade, so the two-unit minimum controls: 2 spares for each of 3 sizes is 6 spare shades, not 1. (Example arithmetic, not a real job.) It could also be read per type or per job. Price it the way it is written and ask.
Mock-ups
MechoShade's guide spec asks for "a mock-up of one roller shade assembly for evaluation of mounting, appearance and accessories," and both it and SWFcontract's add that if the mock-up is not acceptable you rebuild it "until satisfactory results are achieved." SWFcontract's text also asks for it "in sufficient time for Architect's review." That is a shade, a trip and an install you price apart from the main order.
Warranty and field measure
SWFcontract's guide spec asks for its standard limited warranty: limited lifetime on shade hardware and fabric, five years on motorized components. An edited project spec can ask for more. On field measurement, the OGS and SWFcontract texts both require verifying dimensions "by field measurements before fabrication" and showing them on shop drawings, and MechoShade's asks for field measurements "accurate to 0.0625 inch." Your bid sizes are for pricing. Your order sizes come from the field.
How to read the spec with the drawings
The spec says what and how; the drawings say where and how many. A few habits keep them in step:
- Read the spec first and write down every "as indicated on Drawings." Each one is a pointer you have to chase.
- Find out which "Roller Shade Locations" option survived, then check the floor plans' general notes against it. "Provide shades at all exterior windows" and "shades where tagged" give different counts.
- Match the spec's shade types to the drawing tags or the window treatment schedule. SWFcontract's text asks for a schedule that uses "same designations indicated on Drawings," so the tags should line up. When they do not, that is a question.
- Look at head and jamb details for mount and depth, the reflected ceiling plans for pockets, and the electrical sheets for boxes at shade heads.
- Read every addendum for changes to Division 12, the window schedule and the ceilings.
When the spec and the drawings disagree, do not pick the cheaper reading. Look for an order-of-precedence clause in the contract documents, and if it does not settle the point, ask the GC before bid day. Our step-by-step guide to a roller shade takeoff from the window schedule covers the counting side.
Keep a one-page spec summary for every bid: products and basis of design, substitutions, sizing rule, fabrics and roll widths, accessories, motors and voltage, spares, mock-up, warranty, allowances and alternates. It becomes the clarifications section of your proposal.
Turning the spec into your number
Each clause above becomes a line on the estimate or a sentence in the proposal. That build is in how subcontractors price a commercial roller shade bid. If you would rather hand off the reading, our window covering takeoff service reads the Division 12 spec with the drawings and addenda, and the package includes the spec summary and the questions for the GC. What to expect from any outside service is in window covering takeoff services: what you get and how they're priced.
Frequently asked questions
What is spec section 12 24 13?
It is the MasterFormat section number for Roller Window Shades, in Division 12, Furnishings. It holds the written requirements for roller shades on a commercial project: products, fabrics, sizing, accessories, motors, submittals, spare stock, warranty and installation.
Do I have to include the spare shades in my bid?
If the extra materials paragraph is in the project spec, yes: it is part of the contract scope. Price it as written, list it as its own line, and ask the GC whether a "no fewer than two units" minimum applies per size, per type or per job.
Can I bid a manufacturer the spec does not name?
Only if the spec allows substitutions, and then by the process Division 01 sets out, usually before bid day. If the spec says substitutions are not permitted, price the named product or the listed equals, and send any alternate as a separate voluntary price if the bid form allows it.
Does 12 24 13 cover power to motorized shades?
Usually not the power itself, which tends to belong to Division 26. But the OGS master spec's Part 3 says to "connect motor-operated roller shades to building electrical system," so check both sections and ask the GC who provides boxes, wiring and the final connection before you price it.
Is the 12 24 13 spec the same on every job?
No. The section is edited for each project, keeping some options and deleting others. Read the version in the project manual for each bid, even if you bid the same architect last month.