Why Choosing The Right Hinge Matters
Most people think a hinge is just a hinge. It isn't. The wrong hinge on a fire door is not just a waste of money — it's a legal liability. In London, incorrect hinges on fire doors can invalidate your compliance certificate, breach Building Regulations and expose you to unlimited fines.
This guide covers everything you need to know before buying door hinges in the UK.
Door Hinge Sizes — What Do The Numbers Mean?
UK door hinges are measured by their length when open (flat). The most common sizes are:
| Hinge Size | Door Weight | Best For |
|---|---|---|
| 76mm (3 inch) | Up to 30kg | Lightweight interior doors, hollow core |
| 100mm (4 inch) | Up to 50kg | Standard solid internal doors |
| 125mm (5 inch) | Up to 80kg | Heavy solid doors, external doors |
| 150mm (6 inch) | Up to 120kg | Very heavy doors, commercial |
The Most Common Mistake — Builders often say "just use 3-inch hinges." This is only correct for very light hollow-core doors. Most solid internal doors and all fire doors need 100mm (4-inch) hinges minimum. Always check the door weight — it's usually on the manufacturer's data sheet.
How Many Hinges Does A Door Need?
Standard Internal Doors
Minimum 2 hinges for lightweight doors under 40kg. We always recommend 3 hinges for better alignment and longer life — especially on solid doors.
Fire Doors (FD30S / FD60)
Minimum 3 fire-rated hinges — legally required. Some heavy FD60 doors require 4. This is non-negotiable under UK fire safety regulations.
Fire Rated Hinges — What You Must Know
If you are fitting a fire door, standard hinges are not acceptable. You must use fire-rated hinges that carry certification to BS EN 1935 and have been tested as part of a fire door assembly.
FD30 Fire Door Hinges
- Must be CE marked and fire-rated to at least 30 minutes
- Steel or brass — both acceptable for FD30
- Minimum 3 hinges per door
- Ball-bearing type recommended for self-closing doors
FD60 Fire Door Hinges
- Must be rated to 60 minutes minimum
- Steel only — brass not acceptable for FD60
- Minimum 3 hinges, often 4 on heavy doors
- Must be from same certified fire door assembly
⚠️ Do Not Buy Online Without Checking: Many hinges sold on Amazon and eBay claim to be "fire rated" but carry no valid UK certification. Always ask for the CE mark, the fire test certificate number and the BS EN 1935 rating. Doorz London only uses fully certified hardware.
Hinge Materials — Which Is Best?
| Material | Best For | Fire Door? | Lifespan |
|---|---|---|---|
| Grade 304 Stainless Steel | All internal doors | ✓ Yes (FD30 & FD60) | 25+ years |
| Solid Brass | Traditional/period properties | ✓ Yes (FD30 only) | 20+ years |
| Zinc Die Cast | Budget internal doors only | ✗ Not for fire doors | 5-8 years |
| Steel (painted) | Budget internal | ✓ If fire-rated grade | 10-15 years |
The Doorz Approach To Hinges
When Doorz London fits your doors, we supply all hardware as part of the job. We use Grade 304 stainless steel ball-bearing hinges on all standard doors and fully certified fire-rated hinges on all fire doors. You never have to guess — we bring everything needed for a correct, legal installation.
We show you our trade invoice for all hardware. You pay cost price plus a small sourcing fee. Zero markup hidden in a builder's quote.
Let Us Handle The Hardware
Stop guessing which hinges you need. Doorz London supplies and fits all door hardware correctly — every time. Free quote, same day response.