Estimate preliminary steel canopy columns, beams, rafters, purlins, bracing, plates and roof sheet quantities.
| Component | Quantity | Total Length / Area | Allowance | Estimated Weight |
|---|
The estimator uses the plan length and projection to establish the basic canopy geometry. Roof slope is then used to determine the sloping roof length for a single-pitch canopy.
The resulting sloping roof area is used for the preliminary sheet quantity.
Rafters are distributed along the canopy length according to the entered maximum rafter spacing. The calculator rounds the number of spaces upward and then equalizes the actual spacing.
Purlins are distributed along the sloping roof projection according to the entered maximum purlin spacing.
The roof sheet calculation uses the sloping roof area and the entered sheet mass per square metre. A separate sheet allowance accounts for overlaps and cutting.
The sheet cover width and stock length are also used to provide an approximate sheet count. Actual sheet ordering should use the manufacturer's effective cover dimensions after side and end laps.
Columns are estimated from the entered number of supports, column length and section mass. Main beams are estimated from the canopy length.
Bracing is treated as an allowance based on the entered number of bracing sets and average brace length.
Individual member allowances are applied to the corresponding material groups, followed by the overall waste allowance.
The cost is a preliminary material-only estimate. Labor, welding consumables, coating, transport, erection, fasteners and foundations are not automatically included.
What does this calculator estimate?
It estimates canopy beams, rafters, purlins, columns, bracing, plates, roof sheets, waste, total steel weight and preliminary material cost.
Does it account for roof slope?
Yes. The calculator converts the horizontal projection into the sloping roof length using the entered roof angle.
How are rafters spaced?
The calculator rounds the required number of rafter spaces upward and distributes them evenly so actual spacing does not exceed the entered maximum.
How are purlins calculated?
Purlins are estimated from the sloping roof length and maximum purlin spacing.
Does it estimate the number of roof sheets?
Yes. The sheet count is estimated from the canopy length and entered effective sheet cover width.
Does it determine the correct steel member sizes?
No. Section sizes must be selected from structural calculations and project requirements.
Can I use this for a cantilever canopy?
Only as a rough material reference. Cantilever canopies require project-specific structural calculations because support reactions and member forces differ substantially.
Is this an exact bill of materials?
No. It is a preliminary estimator. Final quantities should be checked against approved structural and fabrication drawings.