NBC 2020 4.1.6.5 snow drift on a lower roof at a step - peak Ca(0), drift length xd, and the triangular S(x) distribution with code-style visuals.
5 and Fig. -A. 0), and the drift length xd = 5·Cb·Ss·(Ca(0)−1)/γ.
Builds the triangular accumulation factor Ca(x) and the specified snow load S(x) = Is·[Ss·(Cb·Cw·Cs·Ca(x)) + Sr] for ULS and SLS, evaluates up to two source-area (wind-direction) cases and reports the governing one, and draws a code-style cross-section of the balanced snow plus drift surcharge and the S(x) distribution along the lower roof. Accepts Ss/Sr deep-linked from the Climatic Data Map.
Lower-roof leeward drift at a step only. Sliding snow from the upper roof, unbalanced/partial loads, the upper-roof balanced load, and obstruction/valley drift are not covered - use the dedicated snow tools. 0 unless reduced for a separated higher building.
Ss, Sr, and Cw exposure eligibility are engineer-entered and must be confirmed against NBC Appendix C.
Use for preliminary lower-roof drift loads. Confirm climatic values, source-area dimensions for each wind direction, β/separation assumptions, and all other snow load cases before design use.
Other design checker in the same workspace.
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Every tool ships inside the CoLateral desktop workspace, so a result can stay attached to the project, the drawing, and the review trail it belongs to instead of ending up in a loose spreadsheet.
Outputs are design aids and stay in draft until a qualified engineer reviews and approves them.