Part 5 — Building Sections | Sheet by Sheet

 

Plans show you the layout. Elevations show you the faces. But neither tells you what's happening inside the walls.

That's what sections are for.

A building section cuts straight through the house — vertically — and exposes everything plans and elevations leave hidden. It's the sheet that answers the questions contractors ask most: how high is that ceiling? Where does the stair land? What's the structural depth at that beam?

What it shows:

• Interior ceiling heights — room by room
• Stair geometry — rise, run, headroom clearance
• Structural member depths — beams, headers, joists
• Insulation layers and wall assembly thickness
• Roof structure and attic conditions

• Floor to floor heights on multi-storey homes
• Relationship between indoor finished floor and outdoor grade

Types of sections:

Building section — cuts through the full width or length of the house. Shows the big picture — overall height, stair relationship, ceiling transitions.

Stair section — dedicated cut through the stair showing exact rise/run dimensions, headroom clearance, and landing conditions.

Wall section — zoomed-in cut through a single wall assembly. Covered in more detail in Part 6.

Where builders get burned:

Missing headroom at stairs. The stair section shows 6'-8" clearance on paper but the contractor frames a soffit too low because nobody checked the section against the framing plan. It's a common and expensive miss.