A clear sandwich panel schedule gives a supplier more useful information than one total area. This guide explains how to organise roof and wall dimensions into panel lengths, piece counts and questions to resolve before ordering. The examples use hypothetical dimensions, not Bingfa product specifications or real projects. Final quantities and product dimensions should follow the confirmed layout and the selected product documentation.
Quick Answer
Measure each roof slope and each wall elevation separately. Determine the panel laying direction. Use the confirmed effective cover width to calculate the number of panels across the area, then organise the schedule by panel length. Openings, end treatments, cutting and spare panels should be checked separately. Start with the enclosure dimensions rather than the building footprint or total floor area.
Distinguish Four Quantities
| Quantity | Meaning | What to confirm |
|---|---|---|
| Building footprint | The horizontal ground area occupied by the building. | Not the same as the roof or wall area to be covered. |
| Gross and net roof/wall coverage area | The actual enclosure surface area, recorded before and after deducting areas not covered by the specified panels. | Record each roof slope and wall elevation separately, including gable sections and opening locations. Net coverage area alone does not determine how many whole panels to order. |
| Panel schedule | The list of panel types, lengths and piece counts by area. | Organised by panel profile, length and laying direction. |
| Quotation measurement basis | The unit and area definition used for pricing. | May be square metres, piece count or linear metres; the width and length definitions should be stated. |
For a rectangular surface, coverage area equals its measured surface width multiplied by its measured surface length. On a pitched roof, use the actual slope dimensions within the agreed panel scope. For walls, record rectangular and gable portions separately, along with any masonry or other sections that will not receive the specified panels. Record opening areas separately from their effect on the panel order.
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If the core or roof/wall application is still being selected, review the sandwich panel materials guide before fixing the product reference in the quantity schedule.
Calculate Panel Count for Each Roof or Wall Section
For one regular continuous section, measure the width across the panels, perpendicular to their long axes:
Panel count = round up (width to cover ÷ confirmed effective cover width)
The formula gives the side-by-side count for one panel profile and orientation, assuming one panel covers each run along its length. If a run requires more than one panel, count those pieces separately using the confirmed end-lap layout.
Use the selected product’s confirmed effective cover width. Overall panel width is not automatically effective cover width. Once the effective width already accounts for the joint or side lap, do not deduct that overlap a second time.
Different roof slopes, wall elevations and discontinuous areas should be calculated separately, then summarised. Combining separate areas into one dimension before calculation may produce a count that does not fit each area.
Worked Example A: One Continuous Rectangular Section
Illustrative calculation only. Not a Bingfa standard model or a real project.
Conditions:
- One continuous rectangular coverage area.
- The coverage width is 12.3 m, measured perpendicular to the long axis of the panels. Panels are placed side by side across this width.
- Each panel runs 6.0 m along its length. For this example, ordered length is assumed to match required coverage length, with no end lap.
- The assumed effective cover width is 1.0 m.
- Panels are supplied in full-module widths, with the last panel cut at the edge per confirmed details.
- No openings and no end laps; boundary and length follow this example’s assumptions.
Calculations:
Coverage area:
12.3 × 6.0 = 73.8 m²
Panel count across the width:
12.3 ÷ 1.0, rounded up = 13 panels
Preliminary panel schedule:
13 panels, each 6.0 m long
Schedule area using the assumed effective width:
13 × 6.0 × 1.0 = 78.0 m²
The difference between 73.8 m² and 78.0 m² comes from the module rounding and the edge cut in this example. The 78.0 m² figure is not automatically the final invoiced area. It does not include separately confirmed spare panels or other additional quantities.
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Worked Example B: Two Independent Sections
Illustrative calculation only. Not a Bingfa standard model or a real project.
Two independent areas each require 3.2 m of coverage width, measured perpendicular to the panel length. Assume the same panel profile and orientation, an illustrative effective cover width of 1.0 m, and supply in full-module widths. Each run is covered by one panel of the same length. No custom-width production or reuse of offcuts between the areas has been confirmed.
Where reuse of offcuts across areas is not confirmed:
- Area A: rounded up = 4 panels.
- Area B: rounded up = 4 panels.
- Preliminary full-panel requirement: 8 panels.
Combining the two areas into 6.4 m and rounding up would give 7 panels. That combined figure does not confirm that both independent areas can be laid out correctly. If offcut reuse is confirmed after a specific layout review and product check, the schedule can be adjusted.
How Openings Affect Ordering Quantity
Openings raise two separate questions:
- How much net coverage area do the doors and windows reduce?
- Which actual panels change length, count or cutting because of the opening?
An opening may be cut into a full panel, or the approved layout may call for shorter pieces around it. These arrangements can produce different panel schedules even when the net covered area is the same. Mark each opening on the elevation or roof plan, then identify which panel rows it affects and what pieces are needed.
Coordinate the supporting frames, cutting location, edge treatment and joint details with the selected system and project requirements. The quantity calculation does not establish the load capacity of a panel after cutting.
Panel Length, End Treatment and Offcuts
Record what the ordered length measures and how any outer-sheet extension, factory cut-back or end-lap detail is represented within that dimension. Where panels are joined along their length, use the confirmed layout to distinguish ordered panel lengths from installed coverage. Do not add an end-treatment dimension again if it is already included. For systems requiring handed panels, record the specified left- or right-hand orientation.
Confirm available manufacturing lengths, transport constraints and site conditions before finalising the schedule. Lap dimensions and end details are specific to the selected system. Record separately:
- Known cutting allowance.
- Offcuts that may be reusable, pending confirmation.
- Spare panels ordered separately.
Agree the allowance and spare quantity from the actual layout and project requirements. Potential offcuts should only reduce the order when their dimensions, orientation, joints and intended use have been checked. The sandwich roof panel installation guide covers the related installation interfaces.
Have a roof plan or wall elevation ready? Share the available dimensions, opening positions and panel preferences so the supply requirements and outstanding quantity questions can be reviewed.
Discuss Your Roof and Wall Panel Requirements
Buyer Quantity Preparation Table
Use the first table for the quantities and the second for the supporting information. Add a new quantity row whenever the section, product or scheduled length changes. The sample row belongs to Worked Example A and uses hypothetical dimensions. Final product details and the panel layout are confirmed before order release.
Area Quantity Table
| Section / item | Product and width reference | Scheduled length | Quantity |
|---|---|---|---|
| A1 — illustrative rectangular section | Example profile; assumed effective cover width 1.0 m | 6.0 m per panel; no end lap in this example | 13 full-module panels before the final edge cut |
Product and End Treatment Notes
| Item | Information to record for each section |
|---|---|
| Drawing reference | Drawing number, revision and the section or elevation ID. |
| Selected product | Panel profile, core and specification reference; source of the effective cover width. |
| Panel orientation | Direction of the panel length and the side-by-side coverage direction. |
| Length and end details | What the ordered length measures, cut-back or end-lap treatment, and handed orientation where required. |
| Openings and cuts | Opening locations, affected panels, planned cutting and outstanding edge or support details. |
| Cutting allowance | Known layout-related cutting allowance, with the reason recorded. |
| Offcuts and spares | Confirmed reusable pieces and separately agreed spare panels; distinguish these from unconfirmed candidate offcuts. |
| Pending confirmation | Unresolved product, dimension, layout or supply-scope questions. |
Ridge caps, trims, accessories, sealants and fasteners should be listed separately with their appropriate units. Do not apply a uniform accessory quantity per square metre.
Quotation Measurement Basis
Buyers should confirm with the supplier:
- Whether the quotation is based on square metres, piece count or linear metres.
- Which width and length definitions are used for square-metre pricing.
- How openings, special cuts and end treatments are reflected.
- Whether accessories, packing and other scope items are listed separately.
Ask the supplier to state the measurement basis and included items in the quotation for your specific order. Check that the quoted quantities refer to the same panel schedule and drawing revision. For the wider specification and supply-scope factors, review the sandwich panel cost guide.
Frequently Asked Questions
Can I use the building floor area to order sandwich panels?
No. Floor area describes floor space, while the panels cover roof surfaces and wall elevations. A building may also contain mezzanines or additional floors. Measure the actual enclosure surfaces rather than using floor area as the panel purchase area.
Should door and window openings be deducted?
Where an opening will not be covered by the specified panels, deduct it when recording net coverage area. Then check its effect on the ordered pieces. A cutout in a full panel and a layout using shorter panels can produce different piece lists, so confirm the opening and cutting arrangement before changing the order quantity.
How much extra material should I order?
Separate known cutting allowance from agreed spare panels. Only count offcuts as reusable after their dimensions and intended positions have been checked. Set the extra quantity from the confirmed layout and project requirements, rather than assuming the same percentage suits every order.
What should I send for a panel quantity review?
Send the project location, roof plan, wall elevations, opening positions, selected panel type, laying direction and confirmed effective cover width where available. A preliminary layout can support an initial review. Approved information is required before final production release.
Discuss Your Roof and Wall Panel Requirements
Send the project location, roof plan, wall elevations, opening positions, selected panel type and required supply scope. Include the quantity schedule where available, or share the preliminary dimensions and identify what remains to be confirmed.