Design Guides
Proportion & Scale in Millwork
Updated 2 min read
The short answer
Most millwork that looks wrong is not badly made — it is badly proportioned. The single most common error is trim scaled for an 8ft ceiling installed in a 9ft or 10ft room, where it reads as an afterthought. Scale is decided before anything is cut, and it costs nothing to get right.
Scaling to ceiling height
| Ceiling | Baseboard | Casing | Crown | Wainscot height |
|---|---|---|---|---|
| 8ft (2440mm) | 90–140mm | 65–90mm | Small cove or none | 810mm |
| 9ft (2740mm) | 140–180mm | 90–115mm | 100–140mm | 900–1000mm |
| 10ft (3050mm) | 180–230mm | 115–140mm | 140–200mm built-up | 1000–1100mm |
Casing must project further than the baseboard that dies into it, which is why the two are usually upgraded together.
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Proportion rules worth knowing
- Never divide a wall exactly in half
- Wainscot at the midpoint is visually static. One third or two thirds reads far better.
- Heavier elements go lower
- Closed cabinetry below, open shelving above. The reverse looks top-heavy and unstable.
- Full height or a deliberate stop
- A built-in stopping 100–200mm below the ceiling looks like an error. Meet the ceiling with a scribe, or stop clearly lower and make it intentional.
- Panel fields should be equal
- The setting-out matters more than the profile. Panels of visibly different widths across one wall is what makes panelling look applied rather than designed.
- Match the room, not the catalogue
- A profile that looks right in a showroom with 12ft ceilings will look mean in your 8ft room, and vice versa.
- Odd numbers for display
- Three or five shelf bays generally read better than four, because the eye finds a centre.
Answers
Frequently asked questions
- What is the most common millwork proportion mistake?
- Undersized baseboard and casing in rooms with 9ft or 10ft ceilings — extremely common in Calgary infills and newer builds, which are finished with the same 90mm baseboard used in 8ft rooms. It makes the millwork read as a builder default rather than a design decision.
- Can trim be too big?
- Yes. Oversized trim in a low room visually lowers the ceiling and makes the space feel compressed. A 200mm baseboard in an 8ft basement is as wrong as a 90mm baseboard in a 10ft living room — the error is the same, just in the other direction.
- Do I need to keep the same trim throughout the house?
- Within connected sightlines, yes — trim that changes height at an open doorway cannot be resolved neatly. Between floors, or across a closed door, a change is acceptable and sometimes appropriate, since a basement with lower ceilings genuinely wants smaller trim.
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