Unit IIIInterior Graphics II

Sections, Elevations & Details

The technical heart — internal elevations, sections and the detail.

≈ 55 min + a joinery detailByAmogh N P· Architect & interior designer

The technical heart of the course. Learn internal elevations — one wall’s finished face drawn flat-on and keyed by the segmented-circle interior-elevation symbol; sections through the space and through elements, the cut plane drawn heaviest; and the large-scale construction details (1:10, 1:5, 1:1) — the joinery section, the false-ceiling section, the flooring build-up, the jamb, and the skirting and cornice profiles. Then the material poché conventions that identify the cut material, and the detail bubble that keys a detail back to its origin so it is never orphaned.

Learning objectives

By the end of this lesson, you will be able to — mapped to the course outcomes for Interior Graphics II:

CO3 · Apply

Draw an internal elevation keyed by the interior-elevation symbol.

CO3 · Apply

Draw a section through the space and through an element with a heavy cut plane.

CO3 · Create

Draw a large-scale joinery or ceiling detail dimensioned to finished faces.

CO3 · Understand

Apply material poché conventions and cross-reference details back to their origin.

The finished face and the cut

Internal elevations & sections

Internal elevations keyed by the segmented-circle symbol, and sections through the space and through elements with a heavy cut plane.^{[1, 3, 4]}

DiagramThe segmented-circle interior-elevation key on the plan, with an arrow per wall naming each elevation and sheet

DiagramA section through a suspended gypsum-board false ceiling showing suspension, channels, board, cove and concealed LED

The finished wall, flat-on

An internal (interior) ELEVATION is an orthographic, flat-on projection of ONE wall of a room, to scale (typically 1:20). Where a plan or section cuts THROUGH the space, the internal elevation shows the finished vertical FACE: wall panelling, tiling coursing and layout, wainscot/dado lines, joinery fronts (wardrobe shutters, kitchen elevations, TV units), mirrors, art, switch and socket positions and heights, skirting and cornice in outline, and datum levels (FFL, ceiling level, door and window heads). It is keyed from the plan by the INTERIOR-ELEVATION symbol — a circle divided into quadrants with an arrow in each pointing at the wall it represents, each quadrant naming the elevation number and sheet. This segmented-circle key is a distinctive interior-drawing device, different from exterior elevation labelling.^{[1, 4]}

The construction detail

Details, poché & cross-refs

The large-scale construction detail dimensioned to finished faces, the material poché that identifies the cut, and the detail bubble that keys it back to its origin.^{[1, 2, 3]}

DiagramA large-scale joinery section through a base cabinet, dimensioned to finished faces with hardware call-outs

DiagramConventional material hatching (poché) for brick, concrete, timber, stone, insulation, glass and metal in section

DiagramA detail bubble on a section keys bidirectionally to the enlarged detail, which repeats the bubble as its title

Hatching identifies the cut

Each material has a conventional HATCH (poché) so the CUT material reads without a note (IS 962): brick — diagonal hatch / coursing; concrete (RCC) — dots and aggregate triangles; timber — grain lines (end-grain vs long-grain distinguished, plywood shown with laminations); stone/marble — irregular veined hatch; insulation — a soft batt/cloud; earth/fill — irregular diagonal; glass — thin parallel lines or blank with edge lines; metal — tight fine hatch. You hatch ONLY what the cutting plane passes through — not surfaces merely seen beyond the cut — and the poché weight is LIGHTER than the cut outline so the profile still reads. Hatching is material identification, not decoration to fill a wall.^{[1, 2]}

Myth vs reality

At a glance

Aspect	One side	The other
Internal vs exterior elevation	Exterior: the building's outside face	Interior: one wall's finished face, keyed by the segmented circle
Hatching	Myth: decoration to fill the wall	Reality: identifies the CUT material only, lighter than the outline
Detail dimensions	Myth: to the structural face	Reality: to FINISHED faces — what the carpenter must achieve
A detail's location	Myth: self-explanatory, floats free	Reality: keyed by a bubble back to its origin, or it is unbuildable
Line weight in a section	Myth: one even weight	Reality: cut heaviest, seen medium, surface thin

Vocabulary

Key terms

Internal elevation

A flat-on orthographic view of one interior wall's finished face — joinery, tiling, fixtures and datum levels.

Interior-elevation key

The segmented circle with directional arrows on the plan that names each wall's elevation and sheet.

Cut plane (heaviest line)

What the section slices — drawn thickest and poché'd; everything beyond it is lighter.

Poché / hatching

The conventional material hatch on the CUT surface that identifies brick, concrete, timber, stone, etc.

Detail bubble

A circle (detail number / sheet number) that keys a detail bidirectionally to its origin on the plan or section.

Detail title

Name + number + scale on the detail ('Wardrobe Section — Detail 3 / D-501 — 1:5') — never just a drawing.

Apply it

Drawing task

Draw a large-scale (1:5) sectional detail of a base kitchen cabinet or a wardrobe — carcass boards and thickness, shutter with edge-banding, a concealed hinge, a shelf, a drawer with its runner, the toe-kick and the worktop — with the correct timber poché on the cut boards, dimensioned to finished faces, and hardware called out on leaders. Give the detail a title (name, number, scale) and draw the detail bubble that would key it back to its section. Add a small material-hatching key for four materials you used.

Check your understanding

Self-assessment

1. An internal elevation is keyed from the plan by —

2. In a section, you apply material hatching (poché) to —

3. A construction detail must always carry —

In a nutshell

Recap

An internal elevation is one wall's finished face drawn flat-on (≈1:20) — joinery, tiling, fixture heights and datum levels — keyed by the segmented-circle interior-elevation symbol.

Sections cut through the space (floor-to-ceiling) and through elements (the wardrobe, the ceiling); the cut plane is heaviest, everything beyond lighter, and the cut is poché'd.

The construction detail (1:10/1:5/1:1) resolves joinery, ceilings, floors, jambs and profiles — dimensioned to FINISHED faces, with material call-outs and tolerances.

Material poché identifies the CUT material only (brick, concrete, timber, stone…), lighter than the outline — hatching is information, not decoration.

Every detail is cross-referenced by a bubble back to its origin and titled with name + number + scale — an unkeyed detail is unbuildable.

The evidence

References & further reading

[1]David Kent Ballast, Interior Detailing: Concept to Construction, Wiley (joinery, ceiling, floor and junction details — the definitive interior text).
[2]BIS: IS 962:1989 (material conventions, sections, line work and hatching in architectural/interior drawing).
[3]Francis D.K. Ching, Building Construction Illustrated / Interior Design Illustrated (build-ups, junctions, material representation in section).
[4]Rendow Yee, Architectural Drawing: A Visual Compendium of Types and Methods (section/detail types, poché, cross-referencing at professional standard).