Balcony materials on residential buildings
Balconies are specified attachments under regulation 7(2), and Approved Document B guidance reaches down to 11 metres. What that means for decking, soffits, balustrades, screens and drainage.
Balcony materials on a residential building above 18 metres are controlled by regulation 7(2) of the Building Regulations 2010, which requires materials in the external walls and in specified attachments of a relevant building to achieve European class A2-s1,d0 or better. A balcony attached to an external wall is a specified attachment. So the timber decking, the composite soffit and the hardwood handrail that an architect would have detailed in 2015 are not available on those buildings, and the planning drawings need to show something that is.
The threshold that catches people is the second one. Approved Document B gives guidance pointing away from combustible materials in balconies on buildings with a top storey above 11 metres, which reaches a great many five and six storey blocks that sit well below the 18 metre line.
Where balconies sit in the materials restrictions
Regulation 7(2) applies to relevant buildings, meaning buildings with a storey at least 18 metres above ground level that contain one or more dwellings, an institution, or a room for residential purposes such as student accommodation or a care home. Later amendments extended the same treatment to hotels, hostels and boarding houses, and banned metal composite material of the lower reaction to fire classifications in buildings of any height or use.
Specified attachment covers a balcony attached to an external wall, a device for reducing heat gain such as external solar shading, and a solar panel attached to an external wall. The drafting is about attachment to the wall, which is why a balcony is caught and a freestanding item placed on the balcony deck by a resident is not.
Regulation 7(3) carries a short list of exempt components. Read it rather than paraphrasing it, because the exemptions are specific and they are the difference between a compliant detail and a redesign at technical design stage.
The thresholds that change the answer
Three heights matter, and they do different things.
| Height of top storey | What applies |
|---|---|
| Above 11 metres | Approved Document B guidance on avoiding combustible materials in balconies, and sprinkler provision in new blocks of flats |
| 18 metres or more | Regulation 7(2) materials requirement for external walls and specified attachments, and the fire statement duty at Gateway One |
| Above 18 metres | Higher-risk building status under the building safety regime, with its own gateways and duties |
Heights are measured to the floor surface of the top storey above ground level, and ground level is not always the level at your front door on a sloping site. Get the measurement confirmed before the design settles, because a scheme at 18.2 metres and one at 17.6 metres are different projects.
Confirm which edition of Approved Document B applies to your scheme as well. It has been amended several times since 2018 and the transitional provisions turn on when building work starts.
Decking, soffits and balustrades assessed separately
A balcony is an assembly of parts, and each part gets classified.
Decking is the most visible casualty. Timber and wood-plastic composite boards do not achieve A2-s1,d0, so the usual answers are perforated or plank-profile aluminium, steel grating, or a mineral-based paving system on adjustable pedestals. Aluminium decking has become the default on tall residential buildings, and it changes the acoustic character of the balcony: rain on aluminium is audible in the flat behind it, so specify an acoustic mat or a profile designed for it.
Soffits used to be where aluminium composite panels hid. On a relevant building the soffit needs to be sheet aluminium, steel, or a mineral board system, and the fixings and any insulation within the build-up need checking too.
Balustrades divide cleanly. Glass with aluminium or steel framing is straightforward. Timber handrails, timber capping to a glass balustrade and composite infill panels are not. A stainless steel handrail with a thermal break gives the tactile quality that clients want from timber, at a cost.
Privacy screens are the detail that planning and fire pull in opposite directions. A condition requiring a 1.8 metre screen to prevent overlooking has to be satisfied with a material that also satisfies regulation 7, which means obscured glass in a metal frame rather than the timber-framed screen on the planning drawing. Deal with it at application stage by specifying the screen properly in the drawing annotations.
Planters, furniture and what you can actually control
Residents put things on balconies. Fire and rescue services have been consistent in advising against combustible items being stored on balconies in blocks of flats, and several authorities have issued advice after fires that spread through stored materials and furniture.
None of that is controlled by the Building Regulations, because the items are not part of the building. What controls it, if anything does, is the lease and the building's fire strategy. Where the design includes built-in planters, they become part of the construction, and a fixed planter on a relevant building needs a non-combustible container and a substrate that does not support flame spread.
Designers can help without relying on rules. A balcony with a drained upstand and no recessed detail where leaves and rubbish collect is easier to keep clear. Integrated seating in metal removes the incentive to bring timber furniture out.
Drainage, and how it drives the detailing
Balcony drainage is where the materials question meets the waterproofing question.
Open-drained balconies, where water falls through a perforated deck onto a drained and waterproofed structural slab, are the common solution on aluminium systems. They need a fall, a waterproofing layer, and a drainage outlet, and the outlet usually needs to pass through the external wall or connect to a rainwater pipe. Every penetration is a fire stopping detail, and every rainwater pipe on the elevation is a material that needs classifying.
Free-draining balconies that discharge at the edge avoid pipework and cause staining and nuisance to the balcony below. Councils sometimes condition against them for that reason.
Thermal breaks at the balcony connection are a separate matter that interacts with both. A structural thermal break unit carries the load across the insulation line, and its fire performance needs to be confirmed for a relevant building rather than assumed.
Describing the specification on planning drawings
Planning is not the place to prove Building Regulations compliance, and an officer is not assessing reaction to fire classifications. But the materials shown on an approved drawing constrain what you can build, and a materials condition locks it further.
Four practical steps:
- Annotate elevations with the material and the finish, not just a colour, for decking, soffit, balustrade, handrail and privacy screen.
- State the reaction to fire class alongside the material where the building is above 11 metres, so nobody later argues the approved drawing showed timber.
- Avoid submitting a visual of a timber-clad balcony on a tall building. It fixes an expectation you cannot deliver, and the redesign then reads as a reduction in quality.
- Where a materials and samples condition is imposed, respond with a schedule that matches the fire specification, and say so in the covering note.
On a building of 18 metres or more, or seven or more storeys, the application also needs a Fire Statement under the Gateway One arrangements, and the external wall and attachment strategy is one of the things it covers. A fire statement has to be prepared by someone with fire engineering competence: it is a case where a competent professional is legally required, and an AI-assisted draft is a starting point for that professional rather than a substitute. The same is true of the Fire Safety Strategy that follows.
Existing buildings bring the sharpest version of this problem, where the fabric you want to retain and the escape strategy you need cannot both win. We look at that in fire safety in listed buildings.
One honest uncertainty: the treatment of items that are fixed by residents rather than by the developer sits in a gap between the Regulations, the lease and the fire strategy, and building owners are still working out how to manage it. Design the balcony so that the gap matters less.
Browse all 66 PlanScope report types and start a draft, then send the fire documents for professional review before they go to the authority.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. For specialist technical reports, qualified professional input may be required. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Is a balcony covered by the combustible materials ban?
Yes. Regulation 7(2) of the Building Regulations 2010 applies to specified attachments as well as external walls, and a balcony attached to an external wall is a specified attachment. On a relevant building with a storey at least 18 metres above ground level, materials must achieve class A2-s1,d0 or better, subject to the exemptions in regulation 7(3).
Does the restriction apply below 18 metres?
Regulation 7(2) does not, but Approved Document B gives guidance pointing away from combustible materials in balconies on buildings with a top storey above 11 metres, which covers many five and six storey blocks. Separately, metal composite material of the lower fire classifications is restricted in buildings of any height.
Can I still use timber decking on a balcony?
Not on a relevant building, because timber and wood-plastic composite boards do not achieve A2-s1,d0. The usual alternatives are perforated or plank-profile aluminium, steel grating, or mineral paving on pedestals. Aluminium transmits rain noise, so specify an acoustic mat or a profile designed to reduce it.
What about privacy screens required by a planning condition?
They have to satisfy both requirements at once, which normally means obscured glass in a metal frame rather than a timber-framed screen. Specify the screen material in the drawing annotations at application stage so the condition is discharged against something buildable rather than against a visual.
Are residents' planters and furniture controlled?
Not by the Building Regulations, because loose items are not part of the building. Fire and rescue services advise against combustible items being stored on balconies in blocks of flats, and control in practice comes through the lease and the building's fire strategy. Built-in planters are part of the construction and are caught.
How does balcony drainage affect the fire detailing?
Open-drained balconies need outlets that usually penetrate the external wall, and every penetration is a fire stopping detail. Rainwater pipes on the elevation need their own material classification. Free-draining balconies that discharge at the edge avoid pipework but cause staining and nuisance below, and councils sometimes condition against them.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.