How to Read a Window Schedule on House Plans: Every Column Explained

Windows & Doors

The Window Schedule: The One Page on the Plans That Decides the Order, and the Five Things Usually Wrong With It

Somewhere on the drawing set, usually on the elevation sheet or its own page, is a table with a line for every window and door. The manufacturer quotes from it, the framer frames from it, and the inspector checks egress from it. When it disagrees with the floor plan, which it does on half the sets I see, somebody orders the wrong window. Here is how to read it, and how to check it.

From the designer’s side and the builder’s. Both have made every error below.

A schedule, line by line

ID	Type	Nominal (W x H)	R.O.	Hand	Glass	Notes
W01	Casement	30 x 60	30 1/2 x 60 1/2	L	Triple, Low-E	Egress; bedroom 2
W02	Casement	30 x 60	30 1/2 x 60 1/2	R	Triple, Low-E	Egress; bedroom 3
W03	Fixed	72 x 72	72 1/2 x 72 1/2	–	Double, high-gain Low-E	Tempered; sill under 24 in.
W04	Awning	36 x 24	36 1/2 x 24 1/2	–	Double, obscure, tempered	Ensuite; over tub
D01	Entry, fibreglass, 1 sidelight	50 x 80	52 x 82 1/2	LH in-swing	Decorative, tempered	Multipoint lock
D02	Slider, 3-panel	144 x 80	144 1/2 x 80 1/2	OXO	Triple	Header per S-2

What each column means

ID. W for windows, D for doors, numbered. The same ID appears on the floor plan beside the opening and on the elevation. If W05 is on the schedule and not on the plan, or the other way round, somebody will order it or forget it.
Type. Casement, awning, slider, hung, fixed, combination. “Casement” on a 60-in.-wide opening is two casements or a casement and a fixed; the schedule should say which. The types.
Nominal size. Width then height, inches, the size of the unit itself (frame to frame). Not the rough opening, not the glass. Some designers draw in feet-inches (2’6″ x 5’0″); same thing.
Rough opening (R.O.). The framed hole, usually nominal plus 1/2 in. each way for windows, plus more for doors. This column is the manufacturer’s to confirm, not the designer’s to invent; each maker has a sheet. Rough openings.
Hand. Which side the casement hinges on, viewed from outside (L or R; makers differ on the convention, confirm). For doors, left- or right-hand, in- or out-swing. For sliders, O for fixed and X for operating, read from outside: OX, XO, OXO.
Glass. Double or triple, the coating, obscure (privacy) where needed, tempered where the code requires it. Blank here means the manufacturer’s default, which is the cheapest.
Notes. Egress for bedrooms, tempered for glass near floors, doors and tubs, the header reference for big openings, colour if it varies, mulling for combinations, screens, grilles.

How to check a schedule in twenty minutes

Count. Count the openings on each elevation. Count the lines on the schedule, with quantities. They match, or you have found the first error.
Walk the floor plan. Room by room, read the ID at each opening and find it on the schedule. A bedroom with no egress-capable window is the thing to catch here; 0.35 m2 clear opening, no dimension under 15 in.
Check sizes against the elevations. A 72 x 72 on the schedule drawn as a 48 x 60 on the elevation is a scale error, and the manufacturer builds from the schedule.
Check heads. Window head heights usually line up with door heads (6 ft 8 or 8 ft). A schedule where one window is 6 in. taller than the rest beside it is usually a typo.
Check tempered. Anything with a sill under 24 in. from the floor, within 24 in. of a door, in a door, or in a tub or shower wall: tempered or laminated. The schedule has to say it or the maker will not do it.
Check handing against furniture and swing. A casement that cranks out over the barbecue, a door that swings into the closet. Draw the swing on the plan.
Check the big ones against the structural sheet. Every opening over about 6 ft needs a header on the structural drawings. If D02 is 12 ft and S-2 shows a doubled 2×10, call the designer.

The five mistakes in most sets

Schedule and plan disagree on a size because one was revised and the other was not.
No glass column. Every window gets the default, and the north bedrooms do not get triple.
Handing missing or backwards. Casements that open the wrong way for the deck, or two units in one room that should mirror and do not.
Tempered glass not flagged. The inspector flags it after the units are built. Re-glazing on site is $300 a unit.
Nominal written as rough, or the reverse. Every opening a half-inch wrong, in the direction that does not fit.

Questions people ask

What is the difference between nominal and rough opening size?

Nominal is the window’s own outside frame size. Rough opening is the framed hole it goes into, usually about 1/2 in. bigger each way, per the manufacturer’s sheet.

How is window handing written?

For casements, L or R for the hinge side as seen from outside, though conventions vary and the manufacturer’s order form is the one to match. For sliders, X is the moving panel and O the fixed, read left to right from outside.

Who is responsible for the window schedule being right?

The designer draws it; the manufacturer confirms rough openings and code glazing against it; the builder orders from it. In practice the person who checks it is the one who pays for the mistake, which is why I check every one.

Or have it checked

The window schedule takeoff is this check done on your plans by a builder, with a corrected schedule you can hand to three manufacturers. The calculator then prices it line by line.

Window schedule takeoff, $249 Rough openings

Sources and further reading

Ontario’s Building Code: the official page, with the current regulation. Egress is 9.9.10, glazing and windows 9.6 and 9.7, energy is Supplementary Standard SB-12.
JELD-WEN Canada: windows and exterior doors; the rough opening sheets and warranty documents are on the site.

How to Read a Window Schedule on House Plans: IDs, Sizes, Types, Rough Openings, Handing, Glass and Egress Notes, and the Errors to Catch Before Ordering