Which fire-class route does your balcony need to meet?
A balcony at or above 11 metres can satisfy its fire-class requirement by one of two routes, and a pedestal deck sits differently under each. This page sets both out for the build-up you are specifying.
The regulation and the guidance use different heights
Regulation 7(2) of the Building Regulations applies to a relevant building, and regulation 7(4)(a) sets that as a building with a storey at least 18 metres above ground level (SI 2010/2214). Below that height, regulation 7(2) does not engage at all, whatever height a particular balcony sits at within the building.
Approved Document B guidance is pitched at a different number. Its guidance on balcony construction is written around 11 metres, well below the point at which regulation 7(2) starts to apply. Approved Document B guidance describes one way of meeting the regulation it accompanies.
What the gap between the two numbers means for a specification
A building at 15 metres sits below the regulation 7(2) threshold, so that provision does not reach it on height alone. A warranty surveyor working to Approved Document B guidance can still expect the same balcony to meet the 11 metre guidance threshold, because that guidance was never written to the 18 metre line in the first place. Quoting one number as if it settled the other leaves the build-up open to a correction later in the process.
Regulation 2(6)(c) adds a further test on top of the height. A balcony only counts as a specified attachment, and so only falls within regulation 7(2)'s reach, where it is attached to an external wall, a solar shading device, or a solar panel. A balcony outside that definition sits outside regulation 7(2) regardless of the building's height.
Checking the paragraph before you quote it
Approved Document B paragraph references have been miscited elsewhere in circulation, so read the regulation and the guidance paragraph yourself before putting either in a specification. The Approved Document B paragraph 10.12 miscitation sets out one such case and how to spot it.
Route (a) and route (b) under paragraph 10.10
Both routes come from the same paragraph of Approved Document B Volume 1, guidance describing one way of meeting the fire safety regulation, and a balcony only has to satisfy one of them.
| Route | What it requires | Where the pedestal sits | What it leaves open |
|---|---|---|---|
| Route (a): materials routeAsk the manufacturer which standard the pedestal's classification was tested to before quoting it in a submission. | The materials used in the balcony's construction, including the deck surface, must achieve the reaction to fire classification set out in paragraph 10.10(a) of Approved Document B Volume 1. | The pedestal is one of the materials being classified, since it forms part of the balcony build-up this route tests. | Paragraph 10.10(a) does not say how a height-adjustable pedestal is tested or classified on its own, so a manufacturer's classification claim needs checking against the standard it was tested to. |
| Route (b): soffit routeAsk the soffit designer how penetrations are detailed to keep the soffit imperforate over its full area. | An imperforate soffit covers the full area of the balcony at a minimum REI 30 rating in class A2-s1, d0 or better, under paragraph 10.10(b). | The pedestal sits above a soffit doing the fire-resisting work. | The paragraph does not address what happens where the soffit is interrupted by drainage outlets or access hatches, which is worth raising with whoever designed it. |
Drawn from Approved Document B Volume 1 paragraph 10.10 as published. It governs balconies on residential buildings specifically; roof terraces and podium decks reach the fire-class question by a different statutory route.
Four decisions, each with its own governing document
Fire class
Approved Document B Volume 1 paragraph 10.10 sets out two routes to a fire-class answer for a balcony. Which route applies depends on the soffit below it, and that part of the guidance is settled wording. What is not settled is how each manufacturer reads the route its own pedestal sits in, and one published citation of paragraph 10.12 has been read in ways the text itself does not support.
Read the Approved Document B paragraph 10.12 miscitation before you quote that paragraph back to a building control body.
Load
The governing imposed load for a pedestal deck comes from the National Annex to BS EN 1991-1-1, Table NA.2, category A. That part is settled. What is not settled is whether a manufacturer's own load figure was tested against it, because datasheets in this category have been published with the unit missing, the test house missing, the standard missing, or all three.
Falls
Falls and drainage are governed by BS 6229, by LRWA Guidance Note 7, and by NHBC 7.1.4.2, and the three do not fully agree with each other. BS 6229:2018 has been withdrawn and replaced, and you will still find the withdrawn edition cited as current in material from bodies you would expect to have caught the change by now.
Check which edition the document in front of you actually is before you rely on a clause number in it. Separately, NHBC's joint-width rule and the spacer tabs most pedestal systems ship as standard do not sit comfortably together, and no document resolves that for you. It is a question for the supplier, in writing.
Access to the waterproofing
The published access provision is written for outlets, and general inspection of a waterproofing membrane under a pedestal deck has no UK guidance behind it at all. Access to the waterproofing membrane under a pedestal deck sets out what is covered and what is left to the maintenance plan you ask the contractor to commit to at handover.
Get the route confirmed in writing
Paragraph 10.10 sets out two routes to fire-class compliance, but it does not say which one your soffit and slab actually meet. That confirmation has to come from whoever is specifying or supplying the build-up, and it is worth having before anything is ordered.