Flat Roof Joist Calculator

Calculations to BS 5268-2:2002

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1 Enter Joist Details

1.1 Span and joist spacing

This demo version is fixed at 1m clear span. The full version allows any size

Joist spacing

This is the distance between joist centres. Usually 400, 450 or 600mm, but any value can be used up to 610mm max

1.2 Timber strength class and joist size

Automatically calculate suitable sizes

Enter a specific size

2 Loadings

Dead load

Flat roof with asphalt finish (with felt, boarding, insulation, plasterboard & skim), 0.75 kN/m²

Flat roof with felt finish (with stone chippings, boarding, insulation, plasterboard & skim), 0.5 kN/m²

Other

Live load

Flat roof with no permanent access and altitude not exceeding 100m, 0.75 kN/m² UDL & 0.9 kN point load

Most areas exceeding 100m but not exceeding 200m, (excluding parts of Scotland, Pennines, North East England, refer to BS 6399-3), 1 kN/m² UDL & 0.9 kN point load

Flat roof with a permanent access - fixed ladder or staircase, 1.5 kN/m² UDL & 1.8 kN point load

Other

Flat Roof Joist Calculator

1.1 Span and joist spacing

1.2 Timber strength class and joist size

Smart, quick, easy Timber Beam Calculations in just minutes

Calculators

Span tables

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