Supporting Reference

The Architect's Studio Companion, Rules of Thumb for the ExAC

The Architect's Studio Companion: Rules of Thumb for Preliminary Design, written by Edward Allen and Joseph Iano and published by John Wiley & Sons, condenses structural sizing, MEP space planning, daylighting, egress, parking, and code height-and-area information into quick-lookup tables. On Examitect's ExAC study plan it appears as a supplementary reference across many categories, with the heaviest usage in Section 2 (Codes) and parts of Section 1 (Design and analysis).

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Studio Companion overview

Studio Companion at a glance

Full titleThe Architect's Studio Companion: Rules of Thumb for Preliminary Design
AuthorsEdward Allen and Joseph Iano
PublisherJohn Wiley & Sons (Hoboken, New Jersey)
Current editionSixth Edition (2017), ISBN 978-1-119-09241-4 (paperback)
Earlier editionsFive prior editions dating to the 1980s
LanguagesEnglish
Primary audiencePractising architects, intern architects, and architectural students working on the earliest stages of a building design
ExAC relevanceSupplementary reference on Examitect's ExAC study plan, most often paired with the NBC 2020 in Section 2 and with CHOP and CHING in parts of Section 1
Where to accessThrough major Canadian booksellers and academic libraries. Check the Wiley product page for the Sixth Edition for current access options.

Why the Studio Companion matters for the ExAC

The Studio Companion is, in the authors' own words, a "desktop technical advisor for the earliest stages of building design." It reduces complex engineering and code information into quick spatial approximations: span ranges, structural depths, mechanical equipment footprints, daylight apertures, exit widths, and height and area limits. The goal is to let you make defensible preliminary decisions without first running an engineering analysis or opening the full code.

Two things make it useful on exam day. First, it carries parallel content for the International Building Code and the National Building Code of Canada, so the NBC-side chapters reinforce exactly what ExAC Section 2 tests. Second, its rules of thumb run as quick-lookup charts and tables throughout each Section, giving the kind of fast numeric answer ExAC scenarios ask for when a question puts you into early schematic design.

Read it as a quick-recall companion alongside the NBC 2020 and CHING, not as a stand-alone exam text.

How to study the Studio Companion for the ExAC

  • Spend the first 30 minutes mapping the seven Sections so you know which Section answers which kind of question. That orientation alone saves time on study night.
  • Focus on the NBC-side content: occupancy classifications in Section 1, egress geometry in Section 5, and the height and area tables in Section 7.
  • Tab the structural span and depth charts in Section 2 for wood, masonry, steel, sitecast concrete, and precast concrete. You want to reach a number in seconds, not minutes.
  • Use Section 4 as a space-planning checklist for mechanical rooms, vertical shafts, and horizontal service zones whenever a scenario puts you into early design development.
  • Read it alongside the primary references: NBC 2020 for code, CHING for assemblies, CHOP for practice context.
  • Test recall with scenario questions. Rules of thumb stick when you apply them to a situation, not when you re-read the tables.

ExAC sections the Studio Companion supports

  1. Section 1

    Supplementary reference for schematic design, design development, and engineering coordination categories. Sections 1 through 4 of the book are cited together for early design decisions.

  2. Section 2

    Supplementary reference across many Section 2 categories: NBC occupancy classification, building size, egress, barrier-free design, and structural loads. This is where the Studio Companion carries the most exam weight.

  3. Section 3

    Limited supplementary use, mostly through the daylight chapter (Section 3 of the book) and the MEP chapter (Section 4) where they intersect with building science.

Inside the Studio Companion, the seven Sections

The Sixth Edition is organized into seven Sections that move from code-driven decisions through structure, daylight, services, egress, parking, and height and area. Knowing the shape of the book makes it much faster to find a number on study night.

SectionWhat it coversWhere it lands on the ExAC
Section 1
Designing with Building Codes		 Building codes and zoning, occupancy classifications under the International Building Code and the National Building Code of Canada. Section 2 (NBC occupancy classification, defined terms, code structure). Cited as supplementary across many Section 2 categories.
Section 2
Designing the Structure		 Selecting, configuring, and sizing structural systems: wood, masonry, steel, sitecast concrete, precast concrete, including practical spans and live load ranges. Section 2 (structural loads and design references); Section 1 (engineering coordination and schematic design).
Section 3
Designing with Daylight		 Daylight design criteria, sky cover and solar geometry, building siting and shape, sidelighting, and toplighting with aperture sizing rules. Section 1 (schematic design and design development); Section 3 (building science and sustainable design literacy).
Section 4
Designing Spaces for Mechanical and Electrical Services		 Heating and cooling system selection, passive systems, vertical and horizontal service distribution, plumbing, and electrical and communications. Section 1 (engineering coordination and design development); Section 3 (building science).
Section 5
Designing for Egress and Accessibility		 Components of the egress system (exit access, exit, exit discharge), accessible routes, egress for assembly spaces, and sizing the egress system under the IBC and NBC. Section 2 (means of egress, occupant load and exiting, barrier-free design). Cited as supplementary across multiple Section 2 categories.
Section 6
Designing for Parking		 Parking facility types, accessible parking, surface and structured parking layouts, helix and split-level structures, and sizing rules. Section 1 (site analysis and schematic design where parking is part of the program).
Section 7
Designing with Height and Area Limitations		 Height and area limitations, mixed-occupancy buildings, mezzanines and atriums, construction types, and the height and area tables for both the IBC and the NBC. Section 2 (building size determination, NBC Parts and requirements, mixed major occupancies). Cited as supplementary across multiple Section 2 categories.

For most ExAC candidates, Sections 1, 5, and 7 carry the heaviest exam load because they speak directly to the NBC content tested in Section 2. Sections 2 and 4 are the next priority for schematic design questions in Section 1. Section 3 supports a smaller set of daylight and sustainability questions.

Key Studio Companion terms every ExAC candidate should know

The Studio Companion uses code and engineering vocabulary the ExAC reuses without redefining. Learn these early so you can move quickly from a question stem to the right rule of thumb.

TermWhat it means in the Studio Companion
Rule of thumbA simplified approximation used during preliminary design to size structure, services, daylight, and code-driven elements before engineering analysis.
Occupancy classificationThe code grouping that describes the activities a building or part of a building is used for. The book carries parallel tables for the IBC and the NBC.
Major occupancyThe NBC term for the principal use of a building or part of a building, used to determine height, area, and construction requirements.
Practical span rangeThe span over which a given structural system is economical and constructable in preliminary design, before detailed engineering.
Live loadLoads from people, furniture, and movable equipment that depend on occupancy. The book tabulates live load ranges by occupancy and by structural system.
Construction typeThe code classification that controls allowable building height and area. The book names construction types by fire-resistance rating and combustibility, for example 3-Hour Noncombustible, 1-Hour Combustible, Unprotected Combustible, and Heavy Timber.
Building areaThe NBC measurement of the greatest horizontal area of the building, tabulated in the book as the area of any single floor, that combines with building height and construction type to set most code requirements.
Building heightThe NBC measurement, counted as the number of storeys above grade, that combines with building area and major occupancy.
Exit accessThe first portion of the egress system, from any point in the building to a designated exit.
ExitThe protected portion of the egress system between the exit access and the exit discharge, typically an enclosed stair or an exit door.
Exit dischargeThe final portion of the egress system, leading from the exit to a public way.
SidelightingDaylight entering through vertical apertures in exterior walls, sized in the book by depth-to-head-height ratios.
ToplightingDaylight entering from above through skylights, monitors, or clerestories, sized in the book by aperture-to-floor-area ratios.

Tips for Intern Architects reading the Studio Companion

The Studio Companion was written for designers in the studio, not students in a classroom. If you're early in your internship under the Internship in Architecture Program (IAP) or its provincial equivalent, here is how to get exam value out of it without trying to read it cover to cover.

Tip 1, read it as a reference, not a textbook. Spend an hour mapping the seven Sections, then put it down. From that point on, open it only when you need a number. Trying to read the book cover to cover is the most common way to waste study time on this title.

Tip 2, focus on the NBC pages, not the IBC pages. The code-driven Sections, most notably 1, 5, and 7, carry parallel content for the International Building Code and the National Building Code of Canada. For the ExAC, the NBC pages are the ones to highlight and tab. The IBC pages are useful for understanding the logic, but they are not what gets tested.

Tip 3, build a one-page structural span cheat sheet. Pull the practical span ranges from Section 2 onto a single page covering wood joists and beams, glulam, light and heavy timber trusses, steel beams and open-web joists, sitecast and precast concrete. That sheet alone will help you make fast scoping decisions on schematic design scenarios.

Tip 4, use Section 4 the next time you walk a mechanical room. The mechanical and electrical space rules become much stickier when you can match them to a room you've actually stood inside. Ask your supervising architect to walk you through a project's mechanical penthouse, vertical shafts, and main electrical room with the book open.

Tip 5, learn the egress vocabulary in Section 5. Exit access, exit, and exit discharge are not interchangeable. The ExAC will ask you to identify which part of the egress system a problem belongs to before it asks you to solve it. Section 5 is the fastest way to internalize the distinction.

Tip 6, treat the height and area tables as a starting point, not an authority. The Sixth Edition reflects the 2015 edition of the NBC. Most of the structure carries forward, but always confirm against the NBC 2020 before relying on a specific number for design decisions or exam answers.

Tip 7, keep it on your desk during practice exams. When you miss a sizing or code question, look up the rule in the Studio Companion right after you read the explanation. Connecting the wrong answer to a page in the book is how the rules of thumb start to surface in recall under exam pressure.

Common ExAC scenarios where the Studio Companion helps

These question types come up across ExAC sittings. The Studio Companion will get you to a workable answer faster than the parent reference will.

  • A schematic design scenario asks you to choose between a flat-plate concrete slab and a one-way joist slab for a given column grid. What span ranges and structural depths support each choice?
  • A code question asks you to determine major occupancy classification for a mixed-use building with retail, residential, and a small daycare. Which NBC occupancy applies to each portion?
  • A scenario specifies an occupant load and asks you to size the exit width and number of exits. How does the egress system break into exit access, exit, and exit discharge?
  • A design development scenario asks how much floor area to reserve for a mechanical penthouse on a 6-storey office building. What space allocations and vertical shaft assumptions does the book recommend?
  • A daylight scenario asks how deep a side-lit perimeter zone can be effectively daylit. What head-height ratio applies?
  • A height and area question gives you a major occupancy and a desired storey count, and asks what construction type meets the NBC limits. How do you read the Section 7 tables to find the answer?
  • A parking scenario asks for the bay width and ramp slope of a structured parking helix for a given level of service. What does Section 6 recommend?

For every one of these, the Studio Companion is faster than the parent reference. Confirm the final answer against the NBC 2020, CHOP, or CHING before locking it in.

How the Studio Companion compares to other ExAC references

The Studio Companion is a quick-lookup tool, not a stand-alone exam text. Use this comparison to decide which book to pick up for which kind of question.

ReferenceWhat it's forHow the Studio Companion relates
The Architect's Studio CompanionNumeric rules of thumb for preliminary design across code, structure, services, daylight, egress, parking, and height and area.The quick-reference layer of the ExAC reading list.
NBC 2020The national model building code, including occupancy classifications, height and area, fire protection, egress, and structural loads.The Studio Companion compresses the NBC's height-and-area logic and egress geometry into one-page summaries. Read the NBC for the authoritative rule; use the Studio Companion to see the rule at a glance.
CHING (Building Construction Illustrated)Building science, assemblies, materials, and detailing through illustration.CHING shows how things are built; the Studio Companion gives the numbers for sizing them. Pair them on Section 1 and Section 3 questions.
CHOPThe full landscape of Canadian architectural practice: profession, business, project delivery, and project phases.Different jobs. CHOP runs the office; the Studio Companion sizes the building. Both can be cited under the same Section 1 category.
Heating, Cooling, Lighting (Lechner)A longer-form text on environmental control systems with worked design logic.Lechner explains why a system works; the Studio Companion gives the rule for sizing it. Use Lechner for understanding and the Studio Companion for first-pass numbers.
Canadian Wood-Frame House ConstructionDetailed prescriptive guidance for Part 9 wood-frame residential construction.The Studio Companion covers wood structural sizing for the broader structural range. The two complement each other for residential and small-building questions.
Architectural Graphic StandardsThe deep visual reference for detailed building design across every system.Both are reference books. The Studio Companion is faster for preliminary sizing; Graphic Standards is deeper for design development detail.

How Examitect reinforces the Studio Companion

The Studio Companion is most useful when you already know which rule of thumb to look up. Examitect's question bank includes scenario questions that point candidates back to the Studio Companion's structural sizing charts, egress geometry, height-and-area tables, and MEP space rules. Each answer explanation calls out which Section of the book carries the answer, so you can re-open the right page rather than searching the whole table of contents.

You also get full-length mock exams that pace you through scenarios where the Studio Companion is the fastest lookup, plus study notes that summarize the NBC-side content the book carries. Try a few sample questions first, then check pricing when you want the full bank.

FAQ

Studio Companion FAQ

The Architect's Studio Companion is a rules-of-thumb reference for the earliest stages of building design, written by Edward Allen and Joseph Iano and published by John Wiley & Sons. The current Sixth Edition (2017) condenses structural sizing, MEP space planning, daylighting, egress, parking, and code height and area into quick-lookup tables and charts.

It is a supplementary reference on Examitect's ExAC study plan. It is most often cited as supporting reading for ExAC Section 2 (Codes) and parts of Section 1 (Design and analysis), alongside primary references like the NBC 2020, CHOP, and CHING.

Preliminary structural sizing, mechanical and electrical service space planning, daylighting, egress and accessibility geometry, parking layouts, and the height and area concepts behind both the International Building Code and the National Building Code of Canada.

Yes. The book carries parallel content for both the International Building Code and the National Building Code of Canada, including occupancy classifications and height and area tables. For the ExAC you focus on the NBC-side content, but the IBC chapters are useful for comparison.

Examitect's ExAC study plan currently cites the Sixth Edition (Allen and Iano, John Wiley & Sons, 2017). Older editions cover similar material but are missing updates such as cross-laminated timber and the most recent code references.

Skim the table of contents to map where each rule of thumb lives, then study the NBC-side code content in Sections 1 and 7, the structural sizing charts in Section 2, and the MEP space-planning rules in Section 4. Use the book as a quick lookup, not a cover-to-cover read.

CHING (Building Construction Illustrated) explains how building assemblies work and how parts go together. The Studio Companion gives numbers: span ranges, structural depths, mechanical equipment footprints, daylight apertures, egress widths. The two pair well for ExAC Sections 1, 2, and 3.

Heating, Cooling, Lighting (Lechner) is a deeper book on environmental controls, with longer explanations and worked design logic. The Studio Companion is a quick-reference companion that delivers preliminary sizing numbers in tables. Use Lechner for understanding and the Studio Companion for first-pass numbers.

Keep exploring

Other ExAC reference books.

The Studio Companion is one of several references on Examitect's ExAC study plan. Continue with the primary references and the broader supporting list.

NBC 2020

National Building Code of Canada. The primary reference for every category in ExAC Section 2.

CHING

Building Construction Illustrated. The visual reference for assemblies, materials, and detailing across Sections 1 and 3.

CHOP

Canadian Handbook of Practice. The practice reference for Sections 1, 3, and 4.

NECB

National Energy Code of Canada for Buildings. Supports envelope and energy questions in Section 2.

Heating, Cooling, Lighting

Lechner's environmental controls reference. The longer-form companion to Studio Companion Section 4.

RSMeans

RSMeans Cost Data. North American construction cost data, used for Section 1 Cost Management questions.

Yardsticks

Hanscomb Yardsticks for Costing. Canadian elemental cost data by building type and region, for Section 1 Cost Management.

Supporting references

The extended reading list of supplementary references that show up across the ExAC reading list.