Cost planning
BOQ vs cost estimate: what should an interior client request?
An early cost estimate helps test affordability. A bill of quantities, or BOQ, organises defined work into measured items with descriptions and quantities. A contractor quotation is that supplier’s offer for a stated scope. These documents can support one another, but they are not interchangeable and none should be read without its assumptions and exclusions.
Match the document to the design stage
During concept design, some sizes and materials may still be undecided. An indicative estimate should identify those assumptions and any provisional allowances. Its purpose is to guide choices, not to promise a fixed final construction price.
A more developed BOQ needs a defined drawing and specification basis. Ask which rooms, trades and items are covered and which information remains outstanding. The document title alone does not establish its level of completeness.
Compare offers on a shared basis
Issue the same current drawings and specifications to each supplier. Compare quantities, units, material descriptions, installation, transport and exclusions as well as the total. A blank item needs clarification; do not assume it is free or included elsewhere.
If one offer is much lower, ask the supplier to confirm the specification and identify substitutions. For example, a furniture quotation that excludes hardware and delivery cannot be compared directly with one that includes them. Record clarifications in writing before selecting the offer.
Keep the cost plan current
When the design changes, update the affected quantities or allowances. Keep a record of approved variations with their cost and timing effect. Distinguish a budget allowance from an accepted supplier quotation, and check quotation validity before ordering. BJ Atelier’s QS and costing scope should be agreed for your project; an indicative furniture estimate does not automatically include a full room BOQ or contract administration.
Your next-step checklist
- Identify the document purpose and assumptions.
- Use the same drawing revision for all quotations.
- Clarify blank items and exclusions.
- Update the cost record when scope changes.
Common questions
Does a BOQ guarantee the final price?
No. The agreed offer, scope, procurement conditions and later changes still need to be considered.
Can an estimate be prepared before all finishes are selected?
Yes, if assumptions and provisional allowances are stated clearly and updated as decisions are made.
Make the idea work for your home.
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Explore design services →Prepared with AI assistance for BJ Atelier. These articles offer general planning guidance. Project-specific dimensions, specifications, professional checks and prices are agreed separately.
