A guide to glass repair.

Whether you are dealing with a "blown" window (condensation between the panes) or accidental damage, acting quickly prevents further structural issues and rising energy bills. This guide outlines what to expect when hiring a professional glazier and the costs involved for 2025/26.

What Does the Work Involve?

• Site Assessment: Identifying the glass type (e.g., float, toughened, or laminated) and measuring the precise thickness and dimensions.
• Safety & Preparation: Securing the area, boarding up if necessary, and removing broken shards from the frame and surrounding floor.
• Surface Repairs: Using specialist resins for chips or polishing kits for light surface scratches that haven't penetrated the glass.
• Unit Replacement: For double glazing, the "beads" are removed, the old unit is lifted out, and a new, factory-sealed unit is installed with fresh spacers.
• Sealing & Finishing: Applying exterior-grade silicone or putty to ensure a watertight seal and cleaning the glass to check for imperfections.
• Waste Disposal: Removing old glass and disposing of it at a licensed recycling or transfer station.

Typical Costs

Total project costs are heavily influenced by the type of glass required. Specialist coatings like Low-E (thermal) glass or acoustic laminates for noise reduction will sit at the higher end of the price spectrum. Always check if the quote includes VAT and the cost of any scaffolding required for upper-floor repairs.

How Long Does It Take?

• Chip or Scratch Repair: 30 to 60 minutes per pane.
• Single Pane Replacement: 1 to 2 hours, depending on the frame type (uPVC vs. Putty-set timber).
• Standard Double Glazed Unit: 1 to 3 hours, including de-beading and cleaning the frame.
• Lead Times: While single panes can often be cut on-site, bespoke double-glazed units typically take 3 to 7 working days to be manufactured.

DIY or Professional?

While DIY kits exist for minor scratches, most glass work should be left to a professional glazier. Handling broken glass carries a significant risk of injury, and incorrect installation can lead to draughts, damp, and invalidated home insurance.

Professional installation is essential for double-glazed units to ensure the vacuum seal remains intact; a DIY mistake here will lead to "blown" windows within months.

Furthermore, replacement windows in the UK must comply with Building Regulations. A professional installer registered with a competent person scheme (like FENSA or CERTASS) can self-certify the work, saving you the hassle of a separate local authority inspection.

Choosing the Right Tradesperson

• Check Accreditations: Look for FENSA, CERTASS, or GGF (Glass and Glazing Federation) membership.
• Verify Insurance: Ensure they have Public Liability insurance to cover any accidental damage to your property.
• Ask about Lead Times: Confirm how long it will take for the glass to be manufactured and delivered.
• Request a Fixed Quote: Ensure the price includes the glass, labour, VAT, and disposal of the old unit.
• Warranty: Ask for a guarantee on the seal of new double-glazed units (typically 5–10 years).

UK Regulations

• Document N (Safety Glazing): Requires safety glass (toughened or laminated) in "critical locations," such as doors, side panels, and windows below 800mm from floor level.
• Document L (Conservation of Fuel): Replacement glass must meet minimum thermal performance standards (U-values) to ensure energy efficiency.
• Disposal: Commercial waste glass must be handled according to the Environmental Protection Act; your tradesperson should provide a waste transfer note if requested.

Common Problems

• Blown Units: Condensation inside the glass indicates the seal has failed. This cannot be "repaired" and requires a new glass unit.
• Incorrect Measurements: Even a 2mm error can prevent a double-glazed unit from fitting or sealing correctly, leading to leaks.
• Poor Drainage: If the window frame's drainage holes are blocked during repair, water will sit against the seal and cause premature failure.
• Using the Wrong Putty: Using standard putty on laminated glass can cause the interlayer to delaminate over time.

Frequently Asked Questions