Why the lowest price misleads
Subcontractors price their own reading of the scope. That produces differences you cannot see in the total:
- Exclusions, often at the bottom or in the conditions: scaffolding, lifting, waste removal, transport.
- Different assumptions: another brand, another colour, another thickness.
- Items that are missing or vaguely described, such as corner profiles or sills.
- Different quantities: one prices your schedule, the other his own take-off.
You end up comparing apples with pears. The cheapest quote is the best on paper and the dearest on site if you have to arrange the missing item yourself.
The same applies when you are the subcontractor pricing the work: what you do not pull from the specification you do not price, and you only find out on site. So the method below works in both directions.
The method in four steps
- List the requested scope from the specification. One line per item, with clause and page. This is your yardstick, not the quote.
- Mark every quote line. Included, excluded or unclear. Note deviations (other material, other colour) alongside.
- Add an allowance for what is missing. Use a price from another quote, from your own price book or an estimate, and label it clearly as a provisional sum (stelpost).
- Compare the totals only afterwards. By then everything stands on the same scope.
An example with three quotes
For a façade the specification asks for five items. The amounts are made up, excluding VAT. The allowances are assumptions that you must confirm with the subcontractor.
| Asked in the specification | Quote A | Quote B | Quote C |
|---|---|---|---|
| Cladding | Included | Included | Included |
| Sub-structure | Included | Included | Included |
| Sills, RAL 7016 | Included | Included | Included |
| Corner profiles | Included | Included | Unclear |
| Scaffolding | Included | Excluded | Included |
| Quoted amount | €71,500 | €64,200 | €69,800 |
| Allowance for what is missing | 0 | + €6,800 (scaffolding) | + €1,500 (corner profiles) |
| Comparable with the specification | €71,500 | €71,000 | €71,300 |
Quote B looks €7,300 cheaper than A, but without scaffolding. With the allowance the gap is €500, which is within the margin of what you still do not know. What you ask then decides it: will B confirm the scaffolding for less, will C confirm the corner profiles within its quote? Quality, programme and references are not weighed here yet.
Common exclusions to watch for
Some exclusions come back again and again. Check them in every quote, even if the specification does not mention them:
- Scaffolding and access equipment: often priced by the main contractor or by you, and rarely stated the same way in both documents.
- Lifting, transport and waste removal: small items that add up to a sizeable amount.
- Detailing around openings: corner profiles, sills, reveal finishing and connections to window frames.
- Fire-resistant or ventilating parts: cavity barriers, fire stops and ventilation profiles that sit on a different detail from the one in the specification.
- Preparatory work: measuring up, shop drawings, samples and inspections.
What the table does not show
The table tests the scope only. After that come the things you do not put in a table: the subcontractor's programme and capacity, the risk of variations if a quote is based on an older revision, the payment terms and the references. Put those side by side separately, and let them count only once the scope is equal. That way a good programme does not cover a gap in the scope.
What to ask the subcontractor
- Which items in the specification are not in your price? Please confirm in writing.
- Which assumptions did you make on size, colour, brand and thickness?
- Which quantities is your price based on, and do they differ from the schedule in the specification?
- Are scaffolding, lifting, waste removal and transport included? If not, at what amount?
- Which revision of the drawings and specification did you price?
- How long is your quote valid?
Put the answers in your table and remove the allowances where the subcontractor confirms. If a quote contradicts the specification, follow the same path as in Specification and drawing contradict each other. If you need quantities to test the quotes, see Calculating net façade area.
Record your comparison
Keep the table with the project, with the date of each quote, the version of the specification you tested against and the allowances you used. If a subcontractor is chosen later, you know exactly what you accepted and what you still had to ask. If an allowance turns out to be wrong, you can also see where your estimate was off and adjust it on the next project.
How Modou helps
Modou takes the specification as the starting point and lays every quote next to it: what is included, what deviates and what is missing. The scaffolding, the amounts and the allowances stay with you, and Modou never sends a quote. Read how it works or start with your project.