Short answer: send current drawings, the relevant specification, a written scope, programme dates, project location, access and delivery information, and the commercial basis of the enquiry. If any item is not confirmed, identify it as an assumption rather than leaving the contractor to guess.
A ductwork quotation is more than a measurement exercise. Drawings describe the intended route and system geometry, but the price also depends on how the package can be delivered on the actual site. Identical duct routes can require different labour, access equipment and sequencing when riser access, working hours, delivery routes or surrounding trades change.
What makes a ductwork quotation accurate?
An accurate quotation has a traceable pricing basis. The estimator should be able to identify which drawings and revisions were used, which parts of the specification apply, where the package begins and ends, and which site conditions have been allowed for. That does not mean every design detail must be final before an enquiry is issued. It means the known information, open decisions and assumptions are visible.
This matters when quotations are compared. Two prices may look different because one contractor has included access equipment, supports or second-fix activities while another has excluded them. A clearer RFQ helps the commercial team compare the proposed scope rather than comparing totals that answer different questions.
A practical RFQ checklist
- Current drawings and revisionsInclude layout drawings, sections, details and relevant schedules. Identify the revision status so the pricing basis is clear.
- Project specificationProvide the sections that relate to ventilation, ductwork, supports, terminals, materials and any stated installation requirements.
- Scope of worksSet out the package boundary, known inclusions and exclusions, and the responsibilities of adjacent trades.
- Project location and building environmentLocation, occupancy and working restrictions help establish logistics and whether the opportunity is suitable.
- Programme and zone availabilityShare anticipated start dates, duration, phasing and when each installation area is expected to be genuinely available.
- Tender deadlineState when the quotation is required and who should receive questions about the package.
- Site and access notesInclude working hours, storage restrictions, loading arrangements, lifting requirements, working height and areas that may be released in phases.
- Commercial basisState whether the enquiry is labour-only, supply-and-install or another defined arrangement so quotations are compared on the same basis.
Why drawings alone are not enough
Two contractors can read the same drawing and make different assumptions about supports, openings, insulation, controls interfaces, access equipment or handover information. A layout can show where ductwork runs without stating who forms openings, who supplies associated components, whether access equipment is provided, or what close-out information is expected.
A short written scope does not need to resolve every technical point at enquiry stage. It should identify the pricing basis and flag the areas that need confirmation before award or mobilisation. If the drawing set is still developing, state the revision used for pricing and identify the elements likely to change.
What if some information is not available?
Do not delay an initial conversation simply because the package is incomplete. Send what is available and label the gaps. A contractor can then explain whether the information is sufficient for a firm quotation, whether a budget indication is more appropriate, or whether specific clarifications are needed first.
The important distinction is between a known assumption and a hidden one. A price based on an explicitly stated programme or access assumption can be reviewed later. An assumption that exists only in one estimator's working notes is much harder for a project team to manage.
Make quotation comparisons clearer
Use the same information pack for every contractor and record any clarification issued during the tender period. Ask each tenderer to state exclusions, programme assumptions and the boundary between labour-only and supply-and-install responsibilities. This helps the commercial team normalise the package before ranking prices.
Where information is incomplete, say so. A clearly identified provisional item or open responsibility is more useful than allowing different assumptions to remain hidden. Before award, move the agreed clarifications into the written scope so the contracts manager and site team are working from the same basis as the estimator.
What Cliventa reviews
Cliventa reviews suitable ventilation and ductwork opportunities against the drawings, specification, defined scope, location, programme, access constraints and available site information. We may raise questions where the pricing basis or a package interface is unclear. Delivery, coordination, testing and handover requirements remain subject to the package agreed for that project.
For more detail on service fit, see our ductwork installation and ventilation installation pages. If the package is still being defined, our guide to setting the ventilation scope before award provides the next checklist.