This is the third in the series. The phases guide says where the project is; the drawing set guide says which sheets you issue; this one says how you draw inside them.
Every fact is stated once, in one place. Dimensioning the same distance twice guarantees that one day the two will disagree — and that nobody will know which governs.
The dimension strings
A plan is not dimensioned by «putting measurements where they are needed». It is dimensioned in parallel strings, each answering a different question, stacked from the inside out. The outermost is always the overall; the innermost is always the detail.
Three strings per dimensioned side is usually enough in plan. Inside the building you add a fourth carrying clear room dimensions, which is what matters to whoever furnishes the space and whoever checks accessibility.
CLEAR.What you dimension to
This is the decision that causes the most arguments on site, and it is almost never written down. Does the dimension go to the face of stud or masonry, to the finish face, or to the centreline?
The criterion is not theoretical: you dimension to what the person is going to set out from. On site the rough face gets set out — nobody can set out a finish that does not exist yet. So architecture dimensions to face of structure, and any dimension that cannot shrink is called out separately as clear.
| Callout | What it means | Where it is used |
|---|---|---|
| CLEAR | Minimum dimension that cannot be reduced, measured finished | Clear widths, accessibility, lift shafts, equipment access |
| EQ | Equal spacing between the marked points | Symmetrical grids, setting out, light fittings, façade mullions |
| V.I.F. | Verify in field before fabricating | Work to existing, junctions with structure already poured |
| TYP. | Typical — the dimension repeats in every equivalent case | Thicknesses, setbacks, sill heights |
| F.F.L. | Finished floor level, not top of slab | Every level dimension in sections and elevations |
What belongs on the general notes sheet
- Units and how many decimal places.
- Whether dimensions are to face of structure, finish face or centreline.
- That level dimensions are to finished floor level.
- Do not scale the drawing. The dimension governs over the drawn geometry; if a figure is missing, ask.
The same distance dimensioned on the general plan and again on the enlarged plan, with figures that started out identical.
Somebody corrects one of the two at revision 3. Now there are two current drawings saying different things, both signed.
The general plan carries grids and overalls. The enlarged plan carries the detail, and neither repeats what the other says.
When something changes, it changes in one place, and there is no way for two sheets to contradict each other.
Tagging: the mark points, it does not describe
Here is the idea that holds up everything else, and the one most often misunderstood. A mark
like 205A does not mean «timber door, 3 feet wide». It means: the door
that is row 205A in the door schedule. The tag is a pointer, not a description.
Which is why it matters: if you describe the door on the drawing, the day the ironmongery changes you have fifty sheets to correct. If you tag it, you correct one row.
The drawing says where it is. The schedule says what it is. The moment the drawing starts saying what it is, you have two sources of truth and one will lie.
What gets tagged, and how
- Grids. Numbers one way, letters the other, always in the same order across the whole project. The engineer shares them, so they get agreed once and never moved.
- Doors. Two schools, below.
- Windows. By type —
W-01,W-02— because the same window repeats dozens of times and numbering each one individually is pointless. - Wall types. One code per type, drawn once on the wall types sheet.
- Rooms. Number, name and area. The first digit is the floor: room
305is on level 3. - Section and detail references. The bubble carries the detail number and the sheet it is drawn on. Without the sheet number, the reference forces a search.
The two ways of numbering doors
Simple to start and carries no information. The mark does not say where the door is: finding D-47 means walking the drawing.
And when a door is added halfway through, either everything gets renumbered or a D-48 ends up between D-12 and D-13.
The door into room 205 is called 205. If the room has two, they are 205A and 205B. The mark tells you where it is, and the floor number comes built in.
Adding a door renumbers nothing. It is what most large practices use, and this is why.
The schedules
A schedule is a table where each row is one element and each column one attribute. And it is, formally, the project's source of truth: the drawing locates, the schedule defines.
Door schedule
| Column | What it carries | Why it is there |
|---|---|---|
| Mark | 205A | It is what appears on the drawing. Without it nothing can be cross-referenced |
| Room | 205 · Master bedroom | Locates it without opening the drawing |
| Width × height × thickness | 3'-0" × 7'-0" × 1¾" | What gets fabricated and what gets bought |
| Leaf type | Single swing · sliding · double | Changes the ironmongery and the opening required |
| Material and finish | Leaf and frame, listed separately | They are almost never the same |
| Hand | Left / right, in-swing / out-swing | Ordered at fabrication. Getting it wrong means remaking the door |
| Hardware set | Reference to the hardware schedule | Defined once and referenced, never described here |
| Fire rating | Minutes, where it applies | It is a legal requirement and the authority checks it |
| Details | Head, jamb and sill, with the sheet | Closes the loop with the details sheet |
Window schedule
| Column | What it carries |
|---|---|
| Mark and count | W-03 · 42 units. The count comes from counting elements, not from typing |
| Dimensions and sill | Width, height and sill height above finished floor |
| Operation | Fixed, awning, sliding, tilt and turn |
| Glazing | Thickness, make-up, cavity, coatings |
| Frame | Material, series, colour and thermal break where there is one |
| Performance | Thermal and acoustic, where the project or code requires it |
Room finish schedule
The one most used on site and the one most often done badly. One row per room, columns by surface:
| Room | Floor | Base | Walls | Ceiling | Height |
|---|---|---|---|---|---|
| 205 · Bedroom | Laminate | Timber 3" | Paint, all four | Skim plaster | 8'-0" |
| 206 · Bathroom | Porcelain tile | — | Tile to 7'-0" · paint above | Moisture-resistant board | 7'-8" |
| 207 · Kitchen | Porcelain tile | Tile | Splashback at counter run | Skim plaster | 8'-0" |
When the four walls of a room do not share a finish, open a column per wall (N, S, E, W) or reference an interior elevation. Writing «as per design» hands the decision to whoever installs it.
Wall type schedule
| Code | Overall | Layers, outside to inside | Fire | Extends to |
|---|---|---|---|---|
| W-01 | 6" | Paint · plaster ⅝" · block 4" · plaster ⅝" | — | Slab above |
| W-02 | 4⅞" | Board ½" · studs 3⅝" · board ½" | — | Ceiling |
| W-03 | 6⅞" | Fire board ⅝" ×2 · studs 3⅝" · insulation · board ×2 | 1 hr | Slab above |
The «extends to» column looks like a detail and is not: a wall that dies at the ceiling separates nothing acoustically, and a fire-rated wall that does not reach the slab does not comply. It is one of the first things an inspector looks at.
They should come from the model, not from your hands
All of the above can be done by hand, and was done by hand for decades. What changes today is where the data comes from: a hand-typed schedule is a schedule that goes stale.
The right way is for the schedule to be generated from the elements' properties. If the door in the model is 3'-0", the schedule says 3'-0". If somebody changes it to 3'-6" tomorrow, the schedule changes by itself — and so does the count, and so does the price.
The door width written as text on the drawing: 3'-0" × 7'-0".
The day the door changes, the text does not, and nobody finds out. The drawing looks perfect and lies. It is the single largest source of rework in this whole guide.
The drawing reads the width from the element. So does the schedule. So does the count.
Change the element and all three change at once, because they are the same fact looked at from three places.
What that requires first
- Elements with their properties filled in. It is not enough for the door to exist: it has to know its type, its finish and its hand.
- Types named properly from day one. Renaming types halfway through a project is the most common lost afternoon in the trade.
- Nobody typing text where a parameter belongs. One piece of hard-typed text contaminates the whole schedule, because you can no longer trust any row without checking it.
The chain this opens
When marks point at schedules and schedules come from properties, something appears that did not exist before: the same information serves to draw, to count and to price.
- The mark
205Aon the drawing points at a row. - The row takes its values from the element's properties.
- Counting how many elements carry that type is counting rows: 42 doors of type D-03.
- That count is a quantity, and it enters the estimate under its division.
- When the door changes, the drawing, the schedule, the quantity and the price all change.
That is the real reason it is worth tagging properly: it is not tidiness, it is that the estimate comes out of the same place as the drawing.
The most common mistakes
- Dimensioning the same distance twice on two sheets. One day they stop agreeing.
- Not declaring what you dimension to, and having the site set out to finish face what was dimensioned to structure.
- Dimensioning to top of slab instead of finished floor, and losing two inches of clear height throughout the building.
- Describing on the drawing what belongs in the schedule. «Timber door 3'-0"» on the plan: now there are two sources of truth.
- Numbering doors sequentially on a large project, and being unable to find any of them.
- Hard-typed text instead of a parameter. The drawing looks finished and is lying.
- Schedules that say «as per design». What is not defined gets decided by whoever installs it, and they decide cheap.
Frequently asked questions
How many dimension strings does a floor plan need?
Usually three per dimensioned side: openings and wall runs, structural grid, and the overall. Inside the building you add a fourth with clear room dimensions. The check is that the detail string adds up to exactly the overall.
Do you dimension to face of wall or to centreline?
To whatever the site sets out from, which is the rough face of the wall — nobody can set out a finish that does not exist yet. Grids get their own separate string, because they are the language shared with the engineer. What matters most is declaring it on the general notes sheet and not changing your mind halfway through the set.
How are doors numbered on a drawing?
Two conventions. Sequential (D-01, D-02…) is simple and tells you nothing about location. The one to use on medium and large projects is numbering by room: the door into room 205 is 205, and if there are two they are 205A and 205B. The mark then locates itself, and adding a door does not force a renumber of the project.
What columns should a door schedule have?
At minimum: mark, room, width by height by thickness, leaf type, material and finish of leaf and frame separately, hand, hardware set by reference, fire rating where it applies, and the sheets carrying the head, jamb and sill details.
What is a «clear» dimension?
A dimension that cannot be reduced and is measured finished — clear widths, accessibility, lift shafts, space to service equipment. It governs over the others: if a conflict shows up during construction, something else gets adjusted, never that one.
Why should you never scale a drawing?
Because the drawn geometry can carry inaccuracies the dimension does not, and because printing at another size changes the scale without telling you. The dimension always governs over what is drawn. If a figure is missing, ask — and that question is a formal RFI, not a phone call.