Quick conclusion
Before installing the translucent roofing sheets, it is necessary to measure at least the wavelength, wave height, total width, effective width, and the shape of the two overlapping edges. Counting the number of ribs or measuring the outer width is not enough; the most reliable way is to send the profile drawing or the original intact sheet.
Five dimensions must not be confused
| Terminology | Practical understanding |
|---|---|
| Wavelength | Repeat distance from an equivalent point of a wave to the next point |
| Wave height | Height difference perpendicular from base to top |
| Total width | Physical width from one edge to the other |
| Usable width | Actual coverage width after subtracting the overlapping partside |
| Sheet length | Dimensions along the roof slope; different from the horizontal length |
Field measurement procedure
- Choose sections of corrugated sheets that are intact, clean, and not deformed.
- Place the ruler perpendicular to the wave direction; measure through multiple steps and then divide by the number of cycles to reduce error.
- Use a straight ruler as the reference surface when measuring peak-to-valley height.
- Record the shape of the left/right edge and the overlapping side; take a photo with a ruler.
- Measure at least three positions and record the values, not just one point.
- Send samples or drawings to the factory for confirmation before mass production.
Usable width calculation example
Illustrative example: The sheet has a total width of 1,070mm and the side overlap confirmed by the supplier is 70mm, so the effective width is 1.070 − 70 = 1.000mmThis is just an assumed number to explain the formula; it is not the default effective width of the 9-rib product.Hưng Thịnh Phát.
Measurement form samples to include
- Project name, roof area, date of measurement, person measuring.
- Manufacturer/steel code if readable.
- Number of waves, pitch, height, total width, useful width, length.
- Shape of the crest/trough, auxiliary ribs, overlap edges, slope, and purlin spacing.
- Panoramic photo, sheet-end photo, photos of each measurement, and sample specimen.
Control errors and old roof
Old metal sheets may be sagging, compressed, corroded, or stretched at screw holes. Do not use damaged parts as the sole standard. If the roof has multiple rows of sheet replacement, each area must be checked because there may be different profiles.
Send measurement photos and intact sample sections. The factory will check the profile match capability and respond with a confirmation drawing.
Send documents to receive reportpriceReference sources and limits of use
- ASTM D3841-21: scope of classification, materials, and testing of fiberglass-reinforced polyester panels used in construction; the standard also notes that specific applications may require different performance levels.
- ISO/CIE 10916:2024: procedure to calculate the influence of daylight on building energy performance.
- MCRMA Technical Paper 1: structure, arrangement, and material selection of rooflight for metal roofing systemtype.
- NZ Metal Roofing Manufacturers – Natural Light Materials: compatible with the profile, characteristics, and differences between GRP and Polycarbonate in industrial roofing.
- Nova Construction Products – Rooflight Application Guide: focal point for guiding rooflight and self-drilling screw installation.
Technical limits: This article is used to screen options and prepare quotation data, not to replace construction drawings, structural calculations, light–heat simulations, fire regulations, or specific instructions for the actual roofing system. All thicknesses, spacing, loads, light transmission, fire resistance, durabilityChemicals, warranty, and price must be confirmed with the factory documentation of the shipment before signing the contract or starting construction.
View the product, material, and specification table at guide to choosing Composite/FRP translucent roofing sheets.
Contact Hưng Thịnh Phát for consultation on specifications and pricing at the factory.
