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Defining Tread Run and Introducing Nosing — Factor in the Nosing for Total Depth

Beginner60 mins

Part of project

Stair Tread Sizing · Step 4 of 6

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This segment explains the critical distinction between the 'tread run' (the horizontal distance between risers, typically 10 inches in the example) and the 'effective tread depth' when nosing is present. The video demonstrates that a 1-inch nosing is added to the front of the tread, causing it to overhang the riser below. This means the actual surface you step on (the effective tread depth) becomes 11 inches, even though the structural 'tread run' dimension (measured from riser face to riser face) remains 10 inches. The presenter highlights this as a common point of confusion that needs careful consideration in stair design.

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