Two roof-panel quotations are comparable only when they cover the same product and supply scope. A price per square metre does not tell you whether the offers use the same panel, include the same accessories or provide the same packing and delivery arrangement.
This roof-specific guide builds on our building-material quotation comparison guide. Its focus is turning drawings and supplier offers into one traceable roof-material schedule.
Start with one specification for every supplier
Give each supplier the same drawing revision and list of requirements. Ask them to identify the material or alloy, profile, dimensions, thickness, insulation or infill where applicable, finish and proposed lengths. Record substitutions explicitly; do not compare them as if they were the original specification.
Keep the quotation tied to a supplier product reference and available section drawing. If a finish or colour sample is being approved, record its reference. A product photograph is useful for discussing appearance, but it does not specify every construction detail.
Agree what the quoted area means
Ask whether the price uses effective cover area, a nominal area or another stated basis. Request the panel count, supplied lengths and the coverage convention. Roof area, ordered material area and the area calculated from a supplier’s panel dimensions should not be silently treated as interchangeable.
For illustration only, if a quotation defines effective cover width as 0.20 m and supplied length as 6.00 m, it attributes 1.20 m² to each panel under that convention. That arithmetic does not approve the layout, decide the allowance or tell you how much roof the finished assembly covers after cutting. Have the supplier relate the quantity to the actual drawing.
Compare these lines side by side
| Quotation line | What to record | Useful follow-up |
|---|---|---|
| Main panels | Product reference, lengths, counts and area basis | Which drawing areas does each item serve? |
| Trims and connections | Profile, material, finish, lengths and quantities | Are ridge, eaves, abutments and penetrations covered? |
| Fixings and seals | Item specification, quantity and supply responsibility | Who confirms compatibility and the fixing layout? |
| Product documents | Available instructions and relevant test-document references | Do they apply to the offered product? |
| Packing | Package count, dimensions, weights and identification | Can the destination receive and handle these packages? |
| Delivery | Named destination, delivery term, exclusions and timing basis | Which destination and local costs remain outside the offer? |
Put accessories on a drawing-linked schedule
Assign roof areas and detail references, then connect each accessory to the area or junction it serves. Ask suppliers to separate included components from optional or separately priced ones. Confirm who supplies locally sourced gutters, fixings or seals and how compatibility will be reviewed.
Do not fill an unclear scope with assumptions such as “all installation accessories included.” Ask for named items and quantities. A supplier should also identify information it cannot finalize until a drawing or installation detail is confirmed.
Connect panel lengths to the shipment plan
Ask about package sizes before finalizing lengths. Confirm the loading proposal, receiving location, unloading resources and storage arrangements. If several suppliers share a shipment, keep their package lists separate while building one overall receiving plan.
In the Thailand eight-guesthouse record, the selected panels were recommended in 7.15 m lengths for a roof described as 7 m long. Flooring and ceiling materials were purchased and shipped in phases. The case shows why roof lengths and delivery phases belong in the purchasing discussion; those dimensions are not a default for another project.
Resolve exclusions before comparing the total
Record packing, transport, destination charges, local delivery and installation separately where applicable. Clarify the named delivery point and responsibility split. Confirm what starts the production lead time, how approvals affect it and when shipment timing will be checked.
A sample, quotation or product document can support approval, but it should not substitute for an agreed final schedule. Keep a dated record of changes and the accepted specification before the order is placed.
Common quotation questions
Why can the lowest price per square metre cost more overall?
It may cover a narrower product or accessory package, use a different area basis, or exclude packing and delivery items included elsewhere. Compare the same complete scope first.
Should I copy the supplier’s quantity without checking it?
Ask for the quantity’s connection to the drawing, lengths and coverage basis. Resolve differences with the supplier and project team before ordering.
Can SOMEI review offers from suppliers I already found?
Discuss the required scope through our design and customization coordination service. Send the offers, drawings and unresolved questions together.
Prepare a comparable roof-material enquiry
For the next step, use the roof drawing checklist, review consolidation and container loading support, or send your roof-panel quotations to SOMEI.