Accurate dimensions are essential for a custom tarpaulin. A cover that matches only the top surface may not provide enough overlap for tying, while excessive material can collect water, flap in the wind or create a handling problem. The correct method depends on the object being protected.
Start with the finished size
Always identify whether the dimensions refer to the material before fabrication or the final cover after hems and seams. For most quotations, the customer should provide the required finished length and width. Keep every measurement in the same unit.
Measuring a flat area
- Measure the full length of the area.
- Measure the full width.
- Add the overlap required beyond each edge.
- Check where the eyelets or tie points will sit.
- Confirm whether the sheet needs a slope for water drainage.
For a ground sheet, only a small allowance may be needed. For a roof or stockpile cover, the overlap must be sufficient for secure fixing and weather protection.
Measuring a box or machine
Record the length, width and height. To cover the top and both sides, the required flat width is approximately the top width plus two side drops. The required flat length is the top length plus the front and rear drops.
Add allowance for hems, fastening and movement. Mark any exhausts, handles, wheels, control panels or access doors. Photographs from several angles are extremely helpful.
Measuring a truck or cargo load
Measure the load length, width and maximum height rather than relying only on the vehicle body size. Allow enough side drop for lashing while keeping the cover clear of wheels, hot exhausts and sharp components.
Identify the rope or strap positions and explain how often the cover will be installed and removed. Repeated-use truck covers normally need stronger PVC, reinforced edges and protected corners.
Irregular and shaped covers
A simple sketch can prevent expensive mistakes. Draw the top, front and side views. Label every straight dimension, curve, opening and fixing point. For complex equipment, a site template or professional survey may be required.
Eyelet spacing and reinforcement
Common eyelet spacing includes 50 cm, 1 m and 1 yard, but the correct interval depends on wind load, material and fixing method. Eyelets should sit in a reinforced hem rather than unsupported fabric. Corners usually require extra layers because they carry greater tension.
Large-cover handling
Calculate the approximate weight before ordering. Area in square metres multiplied by GSM, divided by 1,000, gives the base fabric weight in kilograms. Add an allowance for joins, hems, eyelets and packing.
Very large covers may be easier and safer to handle as multiple labelled sections. If one assembled piece is required, confirm lifting, installation manpower and storage space.
Measurement checklist
- Finished length, width and height or drops
- One consistent measurement unit
- Overlap and fixing allowance
- Position and spacing of eyelets or straps
- Openings, sleeves, cut-outs and access panels
- Application, exposure, material and GSM
- Quantity, delivery city and required date
Browse our tarpaulin sizing page or send your sketch for quotation review.