Window Fitters Ltd installs certified FD30 and FD60 fire doorsets based in Croydon, providing FD30 and FD60 door fitting for blocks of flats, commercial offices, schools (learn more on our commercial glazing contracts hub), and hospitals across London and Surrey. Our directly employed fitters install timber and steel fire doorsets with intumescent seals, certified closers, and full Document B compliance, backed by £5,000,000 Commercial Public Liability Insurance and £10,000,000 Employers' Liability Insurance.
Legal & Financial Accountability
- Company Registration: No. 10415531
- Commercial Insurance: £5,000,000 Commercial Public Liability Insurance and £10,000,000 Employers' Liability Insurance on all active sites
- Structural Warranty: 10-Year Frame Guarantee on all fire door frames
- Direct Labour Policy: 100% directly employed crew. Zero unvetted sub-contractors.
Understanding Fire Door Safety Ratings
Fire doors are life-saving safety systems. They stop fire, heat, and toxic smoke from spreading between compartments in a building. They protect escape routes and give occupants time to evacuate. Commercial landlords, block managers, and business owners have a strict legal duty under the Regulatory Reform (Fire Safety) Order 2005 to install and maintain compliant fire doors.
Fire doors are tested to BS 476-22 (British Standard) or BS EN 1634-1 (European Standard). The rating indicates how many minutes the door resists fire:
FD30 Fire Doorsets (30-Minute Resistance)
FD30 fire doors provide a minimum of 30 minutes of fire integrity. They are the most common fire door specification in residential buildings. FD30 doorsets are required for:
- Flat entrance doors in blocks of flats
- Corridor doors in shared hallways and stairwells
- Kitchen doors in open-plan flat conversions
- Bedroom doors in HMO (house in multiple occupation) properties
The “S” suffix (FD30S) means the door also includes cold smoke seals. FD30S is mandatory for flat entrance doors and corridor doors where smoke containment is required.
FD60 Fire Doorsets (60-Minute Resistance)
FD60 fire doors provide a minimum of 60 minutes of fire integrity. They are specified for higher-risk areas including:
- Boiler rooms and plant rooms
- Electrical riser cupboards
- Commercial kitchen doors
- Storage rooms containing flammable materials
- Escape stairwells in buildings above 30 metres (Document B requirement)
FD90 & FD120 Fire Doorsets (Industrial Applications)
FD90 and FD120 fire doors provide 90 and 120 minutes of resistance respectively. These heavy-duty timber or steel fire doors are specified for factories, warehouses, hospital wards, and industrial buildings requiring maximum fire compartment containment.
Timber Fire Door Specifications
Most residential and commercial fire doors use solid timber-core construction. Our certified fire door fitting uses doorsets manufactured to the following specifications:
- Door leaf thickness: 44mm for FD30 doorsets. 54mm for FD60 doorsets.
- Core material: Solid particleboard core or laminated timber stave core for maximum fire resistance and dimensional stability.
- Facing: Hardwood veneer, painted MDF, or laminate finish depending on the architectural specification.
- Frame material: Softwood or hardwood timber lining sets with 15mm or 20mm intumescent strips recessed into the frame rebate.
- Maximum gap tolerance: 3mm to 4mm between door leaf and frame on all four edges. Gaps exceeding 4mm compromise the fire seal and fail inspection.
Steel Fire Door Applications
Steel fire doors are used in industrial and high-security environments. Our fire door installer teams fit pressed steel and hollow metal fire doorsets in:
- Factory and warehouse fire compartment walls
- Hospital corridor and ward separations
- Data centre server rooms
- Electrical switchgear rooms
Steel fire doors achieve FD60, FD90, or FD120 ratings. They are heavier than timber doors (typically 60kg to 120kg per leaf) and require reinforced frame anchoring and heavy-duty pivot hinges.
Intumescent Seal Installation
Intumescent seals are the most critical component of a fire door system. Without correctly installed seals, fire and smoke pass through the gaps between the door leaf and frame.
How intumescent seals work:
- Intumescent strips are recessed into grooves cut into the door leaf edge or frame rebate
- At temperatures above 150°C, the intumescent material expands up to 25 times its original volume
- This expansion seals the gaps between the door and frame, blocking fire and heat transfer
- Combined with cold smoke seals (neoprene or brush-type), they also block toxic smoke at ambient temperatures before the fire reaches the door
Seal positioning:
- FD30 doors: 15mm × 4mm intumescent strip on three edges (both stiles and head). Threshold seal optional.
- FD60 doors: 20mm × 4mm intumescent strip on three edges plus combined smoke seal. Threshold seal required where specified.
Certified Frame-to-Wall Gap Sealing
The gap between the door frame and the surrounding wall structure must be correctly filled to maintain fire integrity. Our fire door installer teams seal this gap using:
- Intumescent mastic sealant for gaps up to 5mm
- Intumescent foam for gaps between 5mm and 10mm
- Mineral fibre packing with intumescent mastic overcoat for gaps exceeding 10mm
Gaps exceeding 10mm in any direction typically indicate that the structural opening is oversised. In these cases, the opening must be reduced with fire-rated plasterboard or timber packing before the frame is installed.
Document B Compliance Checklist
| Building Regulation | Our Installation Standard | Verification Protocol |
|---|---|---|
| Document B (Fire Safety) | FD30 and FD60 certified doorsets with integrated intumescent seals and cold smoke brushes | On-site inspection matching BS 8214 and coordination with LABC |
| Document M (Access & Use) | Clear opening widths ≥ 800mm. Controlled door-closer force ≤ 30N at the leading edge | Calibrated door-closer force gauge checks and frame tolerance audits |
| Document K (Glazing Safety) | Fire-rated safety glass (Pilkington Pyrodur or Pyrostop) in all vision panels | Inspection of safety markings and fire-resistance glazing gaskets |
| BS 8214 (Fire Door Installation) | Maximum 3–4mm gaps on all edges. Correct hinge, closer, and seal positioning | Gap gauge measurement on all four edges during installation |
Fire Door Maintenance & Inspection Service
Existing fire doors require regular inspection and maintenance. The Regulatory Reform (Fire Safety) Order 2005 places ongoing duties on building owners and managers to keep fire doors in working condition. Our maintenance service includes:
- Visual inspection of door leaf, frame, seals, and glazing for damage or wear
- Gap gauge measurement to verify 3–4mm tolerances on all edges
- Door closer adjustment and replacement where closing force is insufficient
- Intumescent seal and smoke seal replacement where damaged or missing
- Hinge tightening and replacement where doors are dropping or binding
- Written inspection report with photographic evidence for compliance records
Supply & Fit or Installation Only
We offer complete contracting flexibility. Choose our Supply and Fit service, where we survey your property, source certified doorsets from leading UK manufacturers, and complete the installation. Or choose our Installation Only package to fit doorsets you have already purchased. We frequently assist block managers by installing landlord-sourced FD30 entrance doors. Read about our standard work formats on our contracts and fitting process pages.
Frequently Asked Questions: Fire Door Installation
What is the difference between FD30 and FD60 fire doors?
FD30 fire doors resist fire for 30 minutes. They are standard for flat entrance doors, corridor doors, and bedroom doors in HMOs. FD60 fire doors resist fire for 60 minutes. They are required for boiler rooms, electrical risers, commercial kitchens, and escape stairwells in tall buildings.
How do I know if my fire doors are compliant?
Check for a fire door certification label or plug on the top edge of the door leaf. Verify that intumescent seals are present and undamaged on three edges. Check that the door closer latches shut from any angle. Gaps between the door and frame should be 3 to 4mm maximum. If any of these checks fail, contact a certified fire door installer for inspection.
Do you install fire doors in blocks of flats?
Yes. We specialise in certified fire door fitting for blocks of flats, including flat entrance doors (FD30S), communal corridor doors, stairwell doors, and bin store doors. We coordinate building control sign-off for compliance with Document B.
Can you maintain and inspect existing fire doors?
Yes. We provide fire door inspection and maintenance services including gap measurement, seal replacement, closer adjustment, hinge repair, and written compliance reports with photographs. Regular inspection is a legal requirement under the Regulatory Reform (Fire Safety) Order 2005.
What building control certification do fire doors require?
Fire door installations must comply with Document B (Fire Safety) and are subject to building control inspection. We coordinate directly with Local Authority Building Control (LABC) or approved private inspectors. We provide complete technical datasheets and installation certificates to secure legal sign-off for your safety records.
Author & Technical Reviewer: Marian Gheorghe
Head Installer & CEO, Window Fitters Ltd
Marian Gheorghe is the Active Director and Team Leader Installer at Window Fitters Ltd. With over 15 years of hands-on experience, he oversees technical safety and UK Building Regulations compliance for all residential and commercial glazing contracts.
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Window Fitters Ltd installs windows, doors, fire doors, and commercial glass facades across London and Surrey. Croydon head office, 40-mile service radius, 100% directly employed CSCS-carded fitters.
Our estimators respond within 24 business hours with a fixed-price quotation.
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