A practical framework for comparing capability, coordination and delivery – not simply profiles and price.

The right steel window supplier is not simply the business with the most polished sales pitch or the lowest price. Steel windows and doors are about more than aesthetics and price. The right supplier is the team that understands the project, has practical construction and façade knowledge, explains system and building limitations, recommends appropriate solutions, coordinates the specified glass and hardware, resolves interfaces, produces detailed shop drawings and carries approved information through manufacture ready for delivery and installation.

Steel windows are custom architectural assemblies that must function and integrate into the building façade. Two quotes may look similar at tender stage, but the installed outcome is directly influenced by the substrate, documentation, manufacturing process, door and system hardware, glass, waterproofing integration and project support. The supplier decision therefore affects more than the product: it affects how clearly the project is resolved before manufacture and how reliably the architectural, aesthetic and functional intent is carried into the building.

In This Article

• What you are really choosing
• Start with the project brief
• Eight supplier capabilities to compare
• Warning signs to investigate
• What to send before the first technical discussion
• Key takeaway

What are you really choosing?

A steel window supplier is a product supplier, technical coordinator and project delivery partner. The supplier must turn architectural intent and project requirements into a defined, fit-for-purpose package that can be reviewed, approved, manufactured and installed.

That requires more than a website, catalogue or showroom. It requires in-depth product and façade knowledge, attention to detail and a process for asking the right questions to identify critical, project-specific information.

You are choosing a partner that understands its product, understands your project and has the knowledge to bring the two together.

Start with the project brief – not the product brochure

Before comparing suppliers, define what the windows and doors must achieve in the building. Blog 2 sets out the outcomes that matter: sealing, function, integration, architectural intent, thermal and acoustic performance, durability and detailed shop drawings. Read The Brutal Truth: Stop Comparing Windows. Start Comparing Façade Performance. You do not need to have every answer at the outset. A capable supplier should help identify the missing information and develop an appropriate solution.

Give every supplier the same project information: current elevations and schedules, opening sizes, operating types, glass and finish requirements, energy and acoustic targets, exposure conditions, threshold and drainage intent. The brief does not need to answer every question; it needs to show what is known so each supplier can prepare a considered quotation and identify the recommendations or information still required.

If a supplier prices an incomplete brief without identifying the gaps, the quotation may look complete while important work remains unpriced or unresolved. This is where later variations, compromised details and responsibility disputes can begin. Treat an early price as preliminary until the scope, assumptions and exclusions are visible and aligned.

Eight supplier capabilities to compare

1. Do they investigate the project before recommending a system?

A capable supplier starts with understanding and technical knowledge, not the catalogue.

Even when a supplier has many years of experience, project-specific questions still require clarification. These may include swing direction, unit function, how the frame meets the surrounding construction, exposure, energy and acoustic requirements. Door-leaf size may affect how the doors can operate. The proposed delivery and glazing sequence may affect access to fixings and final adjustment. The drainage strategy may not align with the proposed steel system, which can increase the risk of water ingress, and the required glass build-up may not suit the glazing bar size. These issues need to be identified before a recommendation is treated as resolved.

The quotation should identify the unit references, colour and finish, door handles and system hardware, glass specification, inclusions and exclusions, responsibility for each project deliverable, payment terms and stated lead time.

If the supplier does not ask these questions, or the quotation does not identify these items, the system may be priced before anyone has established whether it can perform, integrate or maintain the design intent.

Ask: What information do you need before recommending a system? What should be included in the quotation, and which decisions must be resolved before pricing, shop drawings and manufacture?

2. Do they understand where the system works, and where it does not?

No steel window system suits every opening or project. The system substrate, and how it is prepared before manufacturing may not suit the intended environment. Weight capacity, frame depth, hardware limitations, glass compatibility, sealing and the overall configuration must suit the location and use. A knowledgeable supplier can explain why a system suits the project, where its practical limits sit and what must change when an opening becomes larger, heavier or more exposed. One size does not fit all.

Without that understanding, a detail that works for a small window may be repeated on a large operable unit where the loads, hardware and sealing requirements are different.

Ask: What size, weight, opening and glass constraints apply? What requires engineering, consultant input or further design development? Can the supplier provide recommendations or practical alternatives?

3. Do their shop drawings resolve the project before manufacture?

Detailed shop drawings are not an administrative step. They are the point at which architectural intent, product and construction interfaces become information that can be checked before steel is ordered and manufacture begins. They should clearly show unit identification, dimensions, panel arrangement, viewed face, operation and swing direction, relevant sections, glass, glazing beads, hardware, finish, thresholds, clearances and scope responsibilities.

Poor or incomplete shop drawings push unresolved decisions into the factory and then onto the site team or installer. This can lead to incorrect openings, clashes, unsuitable thresholds, missing interfaces and finished units that do not match the intended appearance or function. Revisions must also be controlled so the design, manufacturing and installation teams work from the same approved drawing set.

Ask: What will the shop drawings show? Who checks them? How are consultant comments, client approvals, revisions and the final release for manufacture recorded?

4. Can they coordinate the window package?

The frame, glass, seals, hardware, drainage, finish and surrounding construction have to work as one package. The supplier should coordinate its scope with the architect and/or builder who in turn liaises with the relevant consultants, which may include the engineer, energy assessor, acoustic consultant, façade consultant, glazier and installer. The required participants and responsibilities will vary by project, but the coordination approach should be clear from quotation through to delivery and completion on site.

When this coordination is missing, gaps can appear between packages: the glass may not suit the frame or sash weight, the hardware may not suit the intended use, or the sill, flashing, membrane and drainage strategy may not connect cleanly.

Ask: Who selects and supplies the glass and hardware? Who resolves the head, jamb, sill and threshold details? Who is responsible for flashings, membranes, sealant joints, drainage, glazing, final adjustment and installation tolerances?

5. How are installation, glazing, glass replacement and final adjustments managed?

Steel frames are installed and aligned within prepared openings. Suitable clearances and installation tolerances allow the installer to accommodate normal construction variation while keeping the frame level, plumb and square. Fixings between the frame and adjoining construction should be positioned and finished in a way that supports the required performance and maintains a neat appearance.

Metro generally completes glazing after the frames have been installed. Once the glass is fitted, the operable sash or door carries its full glass load. Hinges, locks, operators, clearances and seal contact can then be checked and adjusted in the installed position so the unit opens, closes, locks and seals as intended. This sequence can also improve access to frame fixings and reduce the weight of individual units during handling. If a pane later requires replacement, the supplier should explain how it can be deglazed and reglazed, including any access, safety or finish constraints.

Pre-glazed units are heavy to transport and install, may require lifting equipment, and can limit access to fixings or adjustments depending on the frame and opening. The important question is not whether one sequence is universally better, but whether the proposed sequence suits the unit size, site conditions, installation method and responsibility split.

Ask: Is glazing completed before or after installation? Who checks alignment, operation, locking and seal contact under the full glass load? How are final adjustments recorded, and how would damaged or broken glass be replaced?

6. Can they explain what supports the proposal and its limitations?

Every custom opening is different. It is not feasible to physically test every individually sized and configured frame, and one tested sample or calculation should not be presented as proof that every custom variation will perform in the same way.

The supplier should explain what supports the proposed solution: system knowledge, design assessment, engineering input, previous applications, component information or project-specific review. They should also state the assumptions, configuration limits and matters that require confirmation by the relevant project professional. If the basis is unclear, the project team cannot judge whether the proposal is suitable or what remains unresolved.

This is consistent with AGWA’s current selection guidance, which treats window and door selection as a fit-for-purpose process involving site requirements, verification and installation, not simply appearance. View the AGWA Window and Door Selection Guide.

7. Can they carry approved information through manufacture and delivery?

Good documentation only has value if the factory builds from it. The supplier should be able to show how approved drawings, glass, hardware, finishes and project requirements are translated into manufacturing information and checked before release.

Controls may include material identification, dimension and alignment checks, weld and finish review, glazing preparation, hardware fit, operation checks, protection, packaging and delivery planning. Without clear checkpoints, errors can travel through production and arrive on site when they are slower, harder and more expensive to correct.

Ask: Which approved documents govern manufacture? What is inspected, by whom and at what stage? How are damage, defects, substitutions or departures from the approved information recorded and resolved before delivery?

8. Is responsibility clear from the first enquiry to aftercare?

A custom steel window package moves through design, approval, manufacture, delivery, glazing, installation and handover. If ownership is fragmented or decisions are made informally, important information can be lost between stages.

The supplier should identify who manages technical questions, shop drawings, approvals, programme updates, delivery, installation coordination, defects and maintenance or warranty information.

Ask: Who is the project contact at each stage? How are decisions and changes recorded? What is provided at handover, and how are defects or service issues raised and tracked?

Warning signs to investigate

1. The system is recommended before the supplier understands what the opening, façade and building need to do.
2. The conversation focuses on profile appearance and price, with little discussion of glass, hardware, sealing, drainage, thresholds or interfaces.
3. Broad performance claims are made without explaining the configuration, assumptions, evidence or limitations behind them.
4. The quotation does not identify drawing revisions, inclusions, exclusions, assumptions or scope boundaries.
5. Shop drawings are treated as fabrication sketches rather than a coordinated record of dimensions, operation, glass, hardware, thresholds and interfaces.
6. Product, material or detail substitutions can occur without a documented review and approval process.
7. Responsibility for glazing, sealing, drainage, installation, protection or defect rectification is unclear.
8. Programme commitments are made without identifying the information, approvals and decisions required before manufacture can begin.

A warning sign does not automatically disqualify a supplier. It tells you where to ask another question. The aim is to expose gaps while there is still time to resolve them, not after manufacture or installation.

What to send before the first technical discussion

• current architectural elevations, plans, sections and window or door schedules
• opening sizes, configurations, handing and intended operation
• available structural, energy, acoustic, bushfire and other project requirements
• glass, privacy, colour, finish and hardware preferences
• site location, exposure, wall construction, waterproofing approach and threshold intent
• proposed supply, glazing, delivery and installation responsibilities
• programme, approval dates and known procurement constraints

Do not wait for every item to be resolved before starting the discussion. A useful supplier will help identify what can be decided now, what needs consultant input and what must be approved before shop drawings are released for manufacture.

Key Takeaway

Choose the supplier that understands the building as well as the product. Look at the questions they ask, the limitations they explain, the details they resolve, the information they document and the responsibility they carry through delivery. Once the proposals describe the same outcome and scope, price becomes meaningful.

Do you have a project you’d like to discuss? Discuss your project with Metro.

Frequently Asked Questions