How to Prepare a BOQ for Aluminium & Glass Works in Qatar
A step-by-step practical guide for contractors, quantity surveyors, and project managers on structuring an accurate Bill of Quantities for glazing packages.
Key Engineering Takeaways
- Define precise alloy grades, thermal break thickness, and Qualicoat coating standards.
- Specify complete glass buildup including Low-E coating surface position and gas cavity type.
- Explicitly reference hardware standards (EN 1154 closers, Grade 304/316 friction stays).
Why Vague Glazing Descriptions Cause Costly Variations
Aluminium and glass packages represent a significant portion of the exterior building budget. Vague tender descriptions such as "Aluminium window with double glass" inevitably result in subcontractor price variations, technical disputes, and delayed approvals. A well-structured BOQ clearly specifies alloy grades, profile system depth, glass coatings, hardware brands, and acoustic/thermal ratings.
Essential Specification Fields in an Accurate BOQ
When preparing or reviewing a glazing BOQ item, ensure the following parameters are explicitly defined:
- • Profile Specification: System manufacturer or approved equivalent, profile depth (e.g. 70mm thermal break), alloy temper (6063-T6), and wall thickness gauge.
- • Surface Finish: Qualicoat Class 1 or Class 2 architectural polyester powder coating, color code (RAL), or anodized film thickness (e.g. 20–25 microns).
- • Glass Composition: Exact buildup (e.g. 6mm Solar-Control Low-E Toughened + 16mm Argon Spacer + 6mm Clear Toughened), U-value, and SHGC targets.
- • Hardware & Gaskets: Country of origin or brand tier (European multipoint locking), friction stays in SS304/SS316, and co-extruded EPDM gaskets.
- • Testing & Compliance: Civil Defense fire certificates, acoustic laboratory test reports, and site water hose testing protocols.
Measurement Methodologies (POMI vs. NRM2)
Window and door items are typically measured by number of units (Nr) with schedule references, while curtain walling, cladding, and large-scale partitions are measured by net area (m²). Clear delineation of flashings, structural brackets, and perimeter silicone sealing avoids site claim disputes.
Have a Project Specification Question?
Our engineering team can assist with profile section calculations, glass performance optimization, and BOQ estimation.