This guide gives you the exact rules, minimum measurements, and practical decisions you need to stay compliant with UK balustrade and guarding requirements.
All details align with Approved Document K and BS EN/BS 6180 principles (but we advise you also verify them on the Gov website here).
Need a balustrade fabricator? Steelgram can help you (learn more).
1. What Height Should Your Balustrade Be?
Domestic balustrades must be 900 mm indoors and 1100 mm outdoors.
This applies to stairs, landings, balconies, terraces, and roof edges.
Domestic properties
- 900 mm: internal stairs, landings, internal floor edges
- 1100 mm: balconies, terraces, roof edges, Juliet balconies
Non-domestic
- 900 mm: stair flights
- 1100 mm: landings, floors, edges
- 800 mm: assembly seating areas
Measurement rule:
Always measure from the finished floor level, not joists, membranes, or a structural layer beneath. This alone prevents many failed inspections.
Summary: Internal = 900 mm. External = 1100 mm. Always measure from finished floor level.
2. When Do You Need Guarding?
Guarding is required anywhere a fall over 600 mm (domestic) or 380 mm (non-domestic) is possible.
Domestic:
- Falls greater than 600 mm
Non-domestic:
- Falls over 380 mm
- Two or more risers on a stair
Always required:
Balconies, decking platforms, roof edges, terraces, light wells, voids, mezzanines.
Windows:
Above ground level, use guarding or restrictors.
Summary: Add guarding anywhere a fall is significant or predictable.
3. What Gaps Are Allowed?
No opening may allow a 100 mm sphere to pass.
This applies to infill bars, glass spacing, wire, cable, or any decorative pattern.
Further rules:
- Don’t use horizontal rails where children may be present.
- Open risers must also block the 100 mm sphere.
Summary: 100 mm max gap + no climbable features.
4. Does Your Balustrade Need Structural Calculations?
Your balustrade must withstand the loads defined in BS EN 1991-1-1.
Most homeowners avoid bespoke calculations by choosing:
- Pre-tested, certified systems, or
- Manufacturers supplying verified load performance data
BS 6180 helps define the design principles behind compliant systems.
Simple load expectation (illustrative only):
- Standard domestic spaces often require around 0.36 kN/m line load.
- High-traffic areas (offices, public spaces) may require 1.5 – 3.0 kN/m.
Always rely on the tested rating supplied with your chosen system.
Summary: Choose systems with verified load ratings unless designing bespoke.
5. What Glass Is Compliant?
Balustrade glazing must be safety glass that meets EN 12600 (Class 3 or higher).
Accepted types:
- Toughened safety glass
- Laminated safety glass (mandatory for most frameless installs)
Key rules:
- Class 3 for general guarding
- Class 2 for door-side panels over 900 mm
- Small panes: 6 mm minimum
- Screens must block a 75 mm sphere
Summary: Use safety-rated toughened or laminated glass; laminated for frameless systems.
6. What Handrail Height Do You Need?
Handrails must be 900 – 1000 mm above the stair pitch line or ramp surface.
Domestic:
- Required with three or more risers
Non-domestic:
- Continuous rails, colour contrast, safe-return ends
- Both sides required where the stair is 1000 mm+ wide
Summary: Fit handrails at 900 – 1000 mm and include them on any stair with 3+ risers.
7. What Stair Measurements Are Legal?
Domestic stairs need rises of 150 – 220 mm and goings of 220 – 300 mm.
Utility:
- Rise: 150 – 190 mm
- Going: 250 – 400 mm
General access (non-domestic):
- Rise: 150 – 170 mm
- Going: 250 – 400 mm
Additional essentials:
- 2 m minimum headroom
- Max 36 risers without a directional change
- Landings must match stair width
Summary: Domestic stairs stay within 150 – 220 mm rise and 220 – 300 mm going.
8. What Are the Rules for Juliet Balconies?
Juliet balconies require 1100 mm guarding, safety glass, and 100 mm max gaps.
Further notes:
- Install restrictors or guarding where installed in front of full-height openable windows.
- Measure height from internal finished floor level.
Summary: Juliet = external guarding at 1100 mm using safety glass.
9. What Are the Requirements for Roofs and Terraces?
Any accessible roof or terrace must have 1100 mm guarding.
Rules:
- Follow BS EN 1991 load resistance
- Maintain the 100 mm max gap
Summary: All accessible roof spaces need compliant guarding.
10. When Do You Need a Vehicle Barrier?
Vehicle barriers are required wherever cars can reach the edge of a floor or deck.
Rules:
- Approx 1100 mm height (per Diagram 4.2)
- Must meet impact-load requirements
- Usually requires engineered or certified proprietary systems
Summary: Vehicle edges require specialist barriers with impact ratings.
11. What Type of Balustrade Should You Choose?
You have a range of material options to choose from. All should be tested to BS EN 1991 loads and designed in line with BS 6180:
Glass balustrades:
- Best for balconies and terraces
- Laminated glass usually required for frameless
- Must meet safety glazing and loading standards
Stainless steel (304 / 316):
- 304 = general outdoor use
- 316 = coastal or high-exposure
- Highly durable, minimal maintenance
Aluminium systems:
- Lightweight, corrosion-resistant
- Good for decking and terraces
Timber balusters:
- Mostly internal
- Must follow 100 mm gap rule
Wire/cable balustrades:
- Outdoor-friendly
- Must maintain tight tension to avoid failing the 100 mm sphere rule
Summary: Match material choice to exposure, load rating, and regulatory needs.
12. What Causes Most Compliance Failures?
Most failures come from incorrect heights, wrong glass, or incorrect measurements.
Common inspection fail points:
- Measuring from joists instead of the finished floor
- Installing 900 mm outdoors instead of 1100 mm
- Misunderstanding handrail height vs barrier height
- Using toughened-only glass where laminated is required
- Gaps exceeding 100 mm
- Horizontal rails in child-accessible areas
- Untested frameless channel systems
Summary: Height, gaps, glass type, and measurement technique cause most failures.
Balustrade Examples
If you’re installing raised decking:
- Over 600 mm drop = 1100 mm balustrade required
- Use corrosion-resistant materials (e.g., 316 stainless or aluminium)
If you’re adding a balcony or terrace:
- Height = 1100 mm
- Laminated glass if frameless
- Check wind load exposure
If you’re renovating internal stairs:
- 900 mm balustrade height
- Handrail required if 3+ risers
- Follow 100 mm gap rule
If you’re fitting a Juliet balcony:
- Height = 1100 mm from internal floor
- Safety glass mandatory
If you’re installing a void/landing barrier:
- Domestic internal: 900 mm
- Some homeowners choose 1000 – 1100 mm for perceived safety
Quick Compliance Checklist
Heights:
- Internal 900 mm
- External 1100 mm
Gaps:
- Max 100 mm
Glass:
- Safety glass; laminated for frameless
Loads:
- Must meet BS EN 1991-1-1
Handrails:
- 900 – 1000 mm
- Required at 3+ risers
Guarding trigger:
- Domestic: > 600 mm
- Non-domestic: > 380 mm
How To Purchase Compliant Balustrade
Pick systems with verified testing and BS EN load certification.
Look for:
- Clear compliant height presets (900 or 1100 mm)
- Laminated glass for frameless designs
- Weather-resistant materials
- UK installation instructions
Avoid:
- Untested imports
- Adjustable balustrades below regulation height
- Designs with footholds
- Glass thickness without certification
You could also contact us here at Steelgram Fabrications, as we can manufacture compliant balustrade bespoke to your project requirements.
Summary: Choose pre-tested systems and avoid unverified products.
16. FAQs
Can I install a balustrade myself?
Yes, but only if the system is pre-engineered. Frameless and commercial installs usually require professional fitting.
Do I need planning permission?
Often no, but balconies and raised platforms may trigger it. Always check your local authority rules.
What thickness should the glass be?
Most domestic systems use 10 – 12 mm toughened, or laminated equivalents. Frameless channels typically require 15 – 21.5 mm laminated.
How far apart should posts be?
Most proprietary systems specify 1 – 1.2 m spacing. Follow manufacturer load testing.
Can I mix materials?
Yes – glass + steel or glass + aluminium are common. Maintain 100 mm gap rules and ensure all components meet the correct load rating.
Is 900 mm ever acceptable outside?
No. External balconies, decking, terraces, and roof edges require 1100 mm.
