Ontario Building Code Tools

OBC Glazing Limit Calculator

Quickly determine how much glazing is permitted on exterior walls of houses using limiting distance and exposing building face, based on the 2024 Ontario Building Code.

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Inputs

Limiting Distance (m)

Exposing Building Face Area (m²)

Optional — Proposed Openings

Proposed Area of Unprotected Openings (m²)

Proposed Percentage of Unprotected Openings (%)

OBC Table 9.10.15.4

Maximum Area of Glazed Openings in Exterior Walls of Houses (%)

Rows: Exposing Building Face Area (m²) | Columns: Limiting Distance (m)

EBFA (m²) \ LD (m)	1.2	1.5	2	2.5	3	4	6	8	10	12	16	20	25
10	8	12	21	33	55	96	100	100	100	100	100	100	100
15	8	10	17	25	37	67	100	100	100	100	100	100	100
20	8	10	15	21	30	53	100	100	100	100	100	100	100
25	8	9	13	19	26	45	100	100	100	100	100	100	100
30	7	9	12	17	23	39	88	100	100	100	100	100	100
40	7	8	11	15	20	32	69	100	100	100	100	100	100
50	7	8	10	14	18	28	57	100	100	100	100	100	100
100	7	8	9	11	13	18	34	56	84	100	100	100	100
Over 100	7	7	8	9	10	12	19	28	40	55	92	100	100

⚠ Based on OBC Table 9.10.15.4 (§ 9.10.15) — applies to houses. Verify applicability and site conditions before use.

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