Commercial Glazing Subcontract Agreements & Trade Terms | Window Fitters Ltd

Commercial Glazing Subcontracting & Trade Supply Agreements

At Window Fitters Ltd (Company Registration No. 10415531), we provide transparent, legally compliant, and structured glazing installation contracts for residential homeowners, property developers, and commercial main contractors across London, Surrey, and surrounding areas (within a 40-mile radius). Whether you are upgrading windows in a residential home or managing a multi-unit commercial refurbishment, our contracts deliver single-point accountability, fixed pricing, and uncompromised quality.

Every project requires the right contractual framework to guarantee timelines, budget control, and regulatory compliance. We offer two primary contract operational models to suit your procurement preferences:

Residential "Supply and Fit" Contracts

For domestic homeowners and private landlords, a Supply and Fit Contract with Window Fitters Ltd guarantees a clear, fully managed installation route. We remove the risk of measuring errors, component mismatches, or regulatory non-compliance by taking full technical responsibility for the entire job.

• Technical Millimetre Survey: Our head surveyor conducts an on-site structural opening survey, assessing lintels, wall reveals, cill projections, and FFL (Finished Floor Level) offsets.
• Factory Direct Sourcing: Sourcing directly from established UK fabricators (Deceuninck, Liniar, Rehau, Origin, Cortizo) to pass exclusive trade discounts directly to you.
• Turnkey Fitting & Site Protection: Heavy-duty dust sheet protection, careful extraction of old timber or metal frames, precision fitting, low-expansion foam insulation, and colour-matched perimeter sealing.
• 5-Year Product & Workmanship Guarantee: Comprehensive product warranty and 5-year workmanship guarantee on all fittings. Learn more on our guarantee page.

Commercial JCT & Subcontract Frameworks

For commercial main contractors, property developers, and architects, Window Fitters Ltd operates under standard UK construction contract frameworks, including JCT Minor Works, JCT Design and Build, and customised Schedule of Rates (SOR) contracts.

Regulatory Compliance & Building Control Coordination

A window installation is only legally sound if it strictly adheres to current UK Building Regulations. All Window Fitters Ltd contracts guarantee compliance with key statutory codes:

Building Regulation Code	Our Contractual Standard	Verification & Certification
Document L (Thermal Efficiency)	Installing A-rated double glazing (Uw 1.2 to 1.4 W/m²K) or ultra-efficient triple glazing (Uw 0.64 to 0.94 W/m²K) to exceed minimum U-value thresholds.	Technical survey specification & LABC inspector sign-off.
Document K (Impact & Fall Safety)	Fitting BS EN 12150 toughened safety glass or laminated security glass in critical impact zones (doors, side panels, low sills).	Glass kitemark inspection & compliance certificate.
Document F (Ventilation)	Integrating background trickle ventilators (8,000 EA for multi-storey habitable rooms / 10,000 EA for single-storey) into sash head profiles unless continuous mechanical ventilation exists.	Pre-configured profile specification.
Document Q & PAS 24 (Security)	Multi-point locking, anti-snap cylinders, internally glazed sashes, and PAS 24 / Secured by Design accreditation on entrance doors.	PAS 24 security certification.

Because we do not hold FENSA self-certification, we coordinate directly with Local Authority Building Control (LABC) or approved private inspectors. We submit site plans, technical data sheets, and arrange inspections to ensure your installation receives legal building control sign-off.

Contractual Transparency & Payment Terms

We pride ourselves on 100% financial transparency. Our contracts feature clear, fair terms for both domestic and commercial clients:

• Fixed-Price Quotations: No hidden charges, unexpected extras, or surprise delivery fees. The quoted price is the final contract price.
• Fair Payment Milestones: Standard residential contracts require a modest deposit upon order confirmation to cover bespoke manufacturing, with the final balance payable upon completion and customer sign-off.
• Commercial Stage Valuations: Monthly stage valuations and retention management aligned with JCT contract schedules.

Frequently Asked Contract Questions

What is the difference between a Supply & Fit contract and Labour Only?

In a Supply & Fit contract, Window Fitters Ltd handles everything: technical survey, profile manufacturing, delivery, installation, and guarantees. In a Labour Only contract, you supply the windows and glass, and hire our skilled glaziers solely for site fitting and sealing.

Are your contracts covered by insurance?

Yes. All contracts are backed by our £5,000,000 Commercial Public Liability Insurance and £10,000,000 Employers' Liability Insurance policies. Residential Supply & Fit contracts also include a 5-year insurance-backed guarantee. View full details on our legal documents page.

How do I request a tender or contract quotation?

You can email your project drawings, window schedules, or Bill of Quantities (BoQ) directly to info@windowfitters.uk or call our Croydon contracts desk on 020 3411 0589.

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