A window schedule and a BOQ can look complete while leaving critical scope decisions unresolved. Reconcile them before pricing to reduce exclusions, incompatible quotations and late design changes.
1. Establish the document hierarchy
Record which drawing revision, window schedule, BOQ and specification govern the enquiry. A supplier cannot coordinate a dependable package when elevations show one type, the schedule shows another and the quantity sheet uses outdated marks.
Create a document register with file name, revision, issue date and status. Mark conflicts as open questions rather than silently choosing one source.
- Architectural elevations and plans
- Window and door schedule
- BOQ or quantity take-off
- Performance specification
- Glass, hardware and finish schedules
2. Reconcile marks, types and quantities
Every mark should point to one opening type, nominal size, location and quantity. Check mirrored units, corner units, coupled frames and fixed-plus-operable combinations separately.
When construction is phased, split quantities by building, floor or release batch. A single total is rarely enough for production and logistics planning.
- Unique mark and opening diagram
- Width × height and quantity
- Handing or opening direction
- Building, level and room reference
- Required delivery phase
3. Define the completed assembly
A profile series does not define a completed window. Review frame, glazing, hardware, seals, drainage, finish and interfaces as one assembly.
Keep glass, frame and whole-window values distinct. ISO 10077-1 covers calculation of thermal transmittance for complete windows and pedestrian doors; the method and configuration therefore matter as much as the number.
- Glass make-up and safety requirements
- Hardware duty and corrosion exposure
- Finish and colour
- Air, water, structural, thermal and acoustic criteria
- Applicable code, method and unit system
4. Make interfaces and exclusions visible
Many quotation gaps sit outside the frame: subframes, flashings, trims, sealants, brackets, screens, access equipment and installation labour. State whether each is included, excluded or supplied by another party.
Clarify the boundary between factory shop drawings, architectural coordination and structural or façade design responsibility.
- Opening and wall build-up
- Fixing substrate and subframe
- Perimeter waterproofing
- Internal and external trims
- Installation, supervision and protection
5. Issue one structured clarification list
Send a numbered request-for-information list with the enquiry and require each supplier to identify assumptions and exclusions against the same structure.
The strongest quotation is not necessarily the shortest or lowest. It is the one that makes scope, evidence, interfaces and outstanding decisions visible.
- Confirmed input
- Open question
- Supplier assumption
- Required evidence
- Decision owner and due date
Questions project buyers ask
Can a supplier quote from a BOQ alone?
A budget indication may be possible, but a dependable project quotation normally also needs opening types, dimensions, performance, glazing, hardware, finish and interface scope.
What is the most common schedule problem?
Inconsistency between marks, drawings and quantities. Resolve the governing revision and record conflicts before comparing suppliers.
Should every unanswered item stop an enquiry?
No. Unknown items can be listed as controlled assumptions, but they must be visible and treated consistently across quotations.
Primary references
ISO 10077-1 — thermal transmittance of windows and doors ↗FGIA — fenestration performance classes and grades ↗Exact systems, performance, price, programme, delivery and warranty require authorised review of the project documents.