Balconies and external decking in a fire statement

Balconies get more attention in a planning stage fire statement than almost any other element of the elevation, and the reason is not aesthetic. A balcony is an attachment to the external wall that sits outside the compartment, often directly above another one, and can carry fuel that nobody specified: decking, furniture, screening, planting. On a relevant building at Planning Gateway One, that is a question the Building Safety Regulator will read carefully.

The starting position is straightforward. Balconies on relevant buildings are treated as specified attachments to the external wall, so the restriction on combustible materials reaches them. What a planning stage statement has to do is describe the approach, not prove the detailed design.

Why balconies attract attention

An external wall that performs well can still be compromised by what is bolted to it. Stacked balconies create a vertical path where flame can reach the underside of the deck above, and the space is outside the sprinkler coverage of the flat behind it.

There is a second reason, and it is about control. Building fabric is fixed at construction. Balcony contents are not. A specification that relies on residents not storing anything combustible outside is a specification that will not hold, and a regulator reading your statement knows that.

Materials and their treatment at planning stage

Balconies attached to the external wall of a relevant building fall within the specified attachments caught by regulation 7 of the Building Regulations 2010 as amended, which limits materials in those locations to the highest reaction to fire classifications. In practice that means non-combustible construction to European class A1 or A2-s1,d0, and it rules out timber decking on the buildings in scope.

At planning stage you are not producing test evidence. You are stating the principle: that balcony construction, including decking, soffits, balustrades and any privacy screen, will be limited to materials meeting the classification required for specified attachments, and that the appearance shown on the elevations is achievable with those materials.

That last clause is where applications come unstuck. An elevation rendered with warm timber decking, submitted with a statement promising class A2 materials, contains a contradiction that a case officer will spot and a design review panel will enjoy. Resolve it in the drawings. Aluminium and mineral-based deck boards can be detailed to read well, but they read differently, and the massing and colour studies should show what will actually be built.

Continuous balconies and vertical spread

Set out the geometry, because it drives the fire engineering.

Recessed balconies raise different questions from projecting ones, because the compartment boundary and the glazing sit in a more complicated relationship. Neither arrangement is inherently wrong. Both need describing.

Relationship to the external wall question

The external wall construction and the balcony question are connected but not the same, and mixing them produces a muddled statement. Deal with the wall build-up first, then the attachments, then the interfaces between them: fixings that penetrate the wall, cavity barriers at the balcony junction, and drainage that passes through the line of the wall.

Drainage deserves a line of its own. Balcony drainage details are a common source of penetrations, and a statement that covers materials but ignores the holes in the wall is incomplete.

What the statement should describe

A Fire Statement submitted at Gateway One is a planning document about the principles that affect the design, siting and access of the building. On balconies, the useful content is:

1. Whether the building is a relevant building, with its height and storey count stated
2. The balcony arrangement in plan and section, including whether they are stacked or continuous
3. The intended reaction to fire classification for decking, soffits, balustrades and screens
4. How balconies relate to escape routes at ground level and to firefighting access positions
5. Drainage and fixing penetrations through the external wall, described in principle
6. Whether any balcony forms part of a smoke control or ventilation strategy

Keep the detailed engineering for the Fire Safety Strategy and for Gateway Two. The planning statement should be readable by a case officer while giving the regulator enough to comment on. Structural questions run alongside this, and our note on disproportionate collapse and building class covers where those two conversations meet.

Conditions covering balcony specification

Authorities often condition balcony materials, and the drafting matters. National guidance discourages conditions that duplicate another regulatory regime, and reaction to fire classification is squarely within the building regulations.

The workable condition is about appearance and substitution: samples or a materials schedule to be approved, with a requirement that any change from the approved schedule is submitted for approval. That controls the planning issue, which is what the building looks like, without the authority trying to police a classification that building control already enforces.

Resist a condition that simply repeats a classification number. If the classification later changes, the condition freezes an obsolete standard into the permission and someone has to apply to vary it.

Amending balcony design later

Changes happen, usually when the contractor prices the deck. The route depends on the scale of the change.

A swap between two visually similar non-combustible deck products is typically a discharge of the materials condition. A change in balcony depth, a change from projecting to inset, or the addition of privacy screens that alter the elevation is more than that, and needs either a non-material amendment under section 96A of the Town and Country Planning Act 1990 or a section 73 application depending on how the permission was framed.

One point specific to Gateway One: if the fire statement informed the regulator's comments and the change goes to something the regulator addressed, expect the authority to want that consultation revisited rather than treating it as a drawing revision.

As an illustrative example, a nine storey residential block at 27 metres with continuous balconies on the south elevation, stacked across all upper floors, submits elevations showing composite deck boards, a section through two storeys with the soffit build-up noted, and a statement confirming class A2-s1,d0 or better for all balcony elements, with drainage penetrations shown in principle at the wall junction. That package answers the question. The same scheme with a rendered image of timber decking and a one-line materials note does not.

A Fire Statement is a document where a professional with fire engineering competence is legally required, under the Building Safety Act 2022 framework and Article 9A of the Development Management Procedure Order 2015. PlanScope can produce a structured draft as a starting point for that professional, never a substitute for them. Enter your postcode on PlanScope to see which reports a scheme is likely to need.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.