Residential Remodeling (B-2) · Lesson 1 of 5

Basement Egress Window Wells: Size, Depth, and Ladder

"Basement Egress Window Wells: Size, Depth, and Ladder" is lesson 1 of 5 in the Residential Remodeling (B-2) Learning Hub. It opens with "Why the Well Is Part of the Exit" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. Why the Well Is Part of the Exit
  2. The Well Size: 9 Square Feet and 36 Inches Both Ways
  3. Deeper Than 44 Inches Means a Ladder or Steps
  4. Find the Well Depth With Simple Subtraction
  5. Drainage, Covers, and the Final Check

The worked example in the course applies this lesson to a realistic job in 6 steps, from "Window opening" through "Ladder details".

What you'll be able to do

  • Explain the main idea of "Basement Egress Window Wells: Size, Depth, and Ladder" in plain language you can use on the exam.
  • Apply this step with confidence: "Deeper Than 44 Inches Means a Ladder or Steps".
  • Apply this step with confidence: "Find the Well Depth With Simple Subtraction".
  • Apply this step with confidence: "Drainage, Covers, and the Final Check".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Basement Egress Window Well: Size and Ladder GRADE ladder slab: 84 in below grade CASEMENT 30 x 30 net 54 in 36 in projection 36 in WELL CHECKS (CRC R319.4) Area: 48 x 36 = 1,728 sq in = 12.0 sq ft (min 9.0) OK Projection 36 in (min 36) OK Width 48 in (min 36) OK Depth = 84 - 36 + 6 = 54 in 54 in is over 44 in: LADDER Rungs 18 in o.c. max: 54 / 18 = 3 spaces Ladder projects 3 in (6 in allowed) Sash swing 30 in fits 36 - 3 = 33 in Window 30 x 30 = 6.25 sq ft (min 5.7) sill 36 in up; well floor 6 in below sill WELL PASSES - ladder required because depth is 54 in (over 44 in) CRC R319.4.1-R319.4.2: at least 9 sq ft, 36 in projection and width, ladder when deeper than 44 in Source: 2025 California Residential Code R319.2 (openings) and R319.4 (Area Wells) CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: Why the Well Is Part of the Exit

When you finish a basement into a bedroom, the egress window is only half of the exit. 2025 CRC R319.1 requires every basement, habitable attic and sleeping room to have at least one operable emergency escape and rescue opening, and R319.7 says new sleeping rooms created in an existing basement must get one (other alterations of an existing basement do not trigger it). If the bottom of the clear opening is below the adjacent grade, R319.4 requires an area well, and an inspector fails a basement bedroom for a bad well just as quickly as for a small window.

Step 2: The Well Size: 9 Square Feet and 36 Inches Both Ways

Under 2025 CRC R319.4.1 the horizontal area of the well must be at least 9 square feet, with a horizontal projection and a width of at least 36 inches each. All three must pass at once: a 40-inch wide well that projects only 30 inches has 40 x 30 = 1,200 sq in = 8.3 sq ft, so it fails on area and on projection. The well must also be large enough for the opening to be fully opened, so a casement sash that swings out needs room to swing.

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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