Double Glazing & Window Fitting FAQs | Window Fitters Ltd

Frequently Asked Questions | Window Fitting, Doors & Building Control

At Window Fitters Ltd, we prioritise transparency, technical accuracy, and client peace of mind. Below are clear answers to common questions regarding window fitting, door joinery, property protection, and UK Building Regulations across London and Surrey.

General Service & Sourcing FAQs

Are you registered with FENSA?

FENSA self-certification applies strictly to standard window replacements in existing structural openings of similar sise. For any project involving structural alterations (such as widening openings, installing lintels, or knocking down brickwork for bifold doors), new extensions, or commercial glazing, Local Authority Building Control (LABC) sign-off is legally required. We coordinate directly with your local council's building control department to submit Building Notices, arrange surveyor inspections, and secure official Completion Certificates. Read our dedicated guide on FENSA vs LABC Certification.

Do you offer Installation Only services?

Absolutely. We provide full Supply and Fit services, but we are also happy to provide an Installation Only service. If you have already purchased your windows or doors, our team of professional window fitters will gladly install them for you.

Can you help me get better prices on windows and doors?

Yes. We have strong connections with top UK manufacturers. We collaborate directly with our clients to help you source high-quality windows, security locks, and aluminium bifold doors at trade prices.

Do you handle window repairs or just installations?

We specialise in both. With over 10 years of experience, we provide complete property fittings and reliable window repairs, including replacing misted double-glazed glass units, and repairing failed locks, hinges, and tracks.

How much does window and door installation cost?

Installation costs vary based on dimensions, materials (uPVC, aluminium, timber, composite), frame styles, and access requirements. Rather than static estimates, we provide exact itemised quotes based on transparent day rates and trade material sourcing. View our comprehensive Window & Door Cost Guide for detailed price tables by window type, door specification, and fitting model.

How long does it take window fitters to install?

Fitting a single standard replacement window takes roughly 1 to 2 hours. A full house window installation (8 to 10 windows) is typically completed in 1 to 2 working days. Single composite front doors take 3 to 4 hours, while multi-pane bifold door sets take 1 full day including weather-sealing and alignment checks.

What is the average lifespan of a window?

Modern uPVC and powder-coated aluminium window frames have an average lifespan of 20 to 35 years with routine hinge lubrication and frame drainage maintenance. Sealed double-glazed glass units (IGUs) typically last 15 to 25 years before thermal seal degradation occurs, at which point a simple glass unit swap restores full performance.

What are common window problems?

The most common window issues include: blown or misted double glazing (moisture between panes), stiff handles or squeaking friction hinges, dropped sash alignment causing the frame to catch, blocked frame weep holes pooling water on sills, and perished rubber weather gaskets causing cold draughts.

Property Protection, Site Care & Workmanship FAQs

How do you protect my home against property damage, floor scratches, and mess?

We take site protection seriously. Our fitters lay heavy-duty floor protection runners, cover furniture with dust sheets, and wear protective shoe covers. Old frames, glass fragments, and plaster dust are continuously vacuumed and cleared throughout the fitting process, ensuring your baseboards, flooring, and interior decor remain undamaged.

How do you prevent inaccurate measurements and rough opening gaps?

Inaccurate fitting is avoided by conducting thorough technical surveys. Our surveyors measure the structural brick-to-brick opening in three locations (width, height, and diagonal squareness), deducting precise 10mm expansion tolerances. This ensures new pre-hung frames fit securely into the aperture without forced masonry cutting or unsightly frame gaps.

When should doors be installed during a house renovation?

External doors should be installed after heavy wet masonry and plastering work is complete (to seal the building envelope), but before final flooring installation or final coat painting. This prevents accidental tool scratches or wet cement splatters from other trades during ongoing building work.

How do you prevent operational issues like sticking, floor drag, or latch failure?

Sticking doors or latch misalignment occur when frames are fitted out of square or sag over time. Our experienced joiners install frames perfectly plumb using spirit levels and composite shims, adjusting 3D flag hinges and multi-point keep plates to guarantee smooth, zero-drag latching.

What accountability and workmanship guarantees do you provide?

Every installation is backed by our 10-year frame and 5-year glass guarantee, a 5-year workmanship guarantee, and an optional Insurance-Backed Guarantee (IBG). All fitters are directly employed, insured with £5M public liability cover, and CSCS-carded for absolute accountability.

Door Fitting, Joinery & Door Building Control FAQs

Does Building Control apply to all external door replacements?

Yes. Under UK Building Regulations (Part L), every replacement external door is a controlled fitting and must meet strict thermal performance standards (maximum U-value of 1.4 W/m²K or door energy rating Band C or better). Whether the door is a solid composite front door, a timber door, or a fully glazed bifold door set, the installation must be registered and certified. If fitting a door requires structural masonry alterations (such as widening an opening or installing a new load-bearing lintel) or occurs in a new extension, Local Authority Building Control (LABC) sign-off is legally mandatory. Read our full guide on FENSA vs LABC for Doors & Windows.

How much would a joiner charge to hang a door?

Hanging a standard internal timber door typically costs between £60 and £120 per door (labour only). Installing external pre-hung composite doors or complex aluminium doorsets ranges higher depending on weather-sealing and structural alignment. For a full breakdown of joinery and fitting rates, visit our Window & Door Cost Guide.

How many doors should a joiner hang in a day?

An experienced joiner typically hangs 4 to 6 standard internal doors per day, including fitting hinges, mortise latches, and door handles. For complex external pre-hung composite or bifold doorsets, a team fits 1 to 2 complete units per day due to the extensive weather-sealing, threshold levelling, and LABC compliance checks required.

What are common mistakes when hanging a door?

The most common door fitting mistakes include: inaccurate frame shimming (causing frame twist and latch binding), trimming too much off door edges (exposing soft core wood or voiding fire door compliance), installing hinges unaligned or upside down, failing to mortise latch plates flush, and miscalculating floor clearance height for carpets.

Additional Guides & Interactive Resources

To help you make the best decisions for your property, we have compiled helpful tools, guides, and comparison tables:

• UK Building Regulations 2026 Guide: Comprehensive technical overview of Approved Documents L, F, B, K, Q, and M.
• FENSA vs LABC Certification Guide: Complete breakdown of door compliance and structural LABC requirements.
• Window & Door Cost Guide: Itemised pricing for uPVC, aluminium, composite doors, and joinery fitting rates.
• Glazing Knowledge Hub: Technical resources, building codes, and installation guides.
• Window & Door Styles Guide: Complete visual guide to window frame styles and opening options.
• Aluminium Foil & DIY Hacks Risk Guide: Building physics analysis of DIY window foil risks.
• Material Comparison Guides: Side-by-side analysis of uPVC, aluminium, and timber.
• How-To Maintenance Guides: Step-by-step care instructions for windows and doors.

Request Your Free Home Survey & Technical Audit

Our expert installers are happy to answer any further questions. Get in touch today for free, professional advice.

• Phone: 020 3411 0589
• Email: info@windowfitters.uk