Plasterboard fire ratings on new-build homes in England

A fire rating in minutes belongs to a tested element, never to a loose board. It depends on the board type and thickness, the number of layers, the studs or joists, the screws, the insulation and the jointing. BS EN 520, the product standard for plasterboard, lists fire resistance among the characteristics linked to systems assembled with plasterboards.

Two different properties both get called a fire rating. Reaction to fire describes how much the board itself adds to a fire, and is given as a Euroclass such as A2-s1, d0. Fire resistance is how long a whole wall, floor or ceiling holds back a fire in a standard test, and is given in minutes.

Approved Document B measures fire resistance on three criteria. R is loadbearing capacity. E is integrity, which stops flames and hot gases getting through. I is insulation, which limits the heat reaching the far side. The minutes are time elapsed in a standard test and should not be read as real time.

A2-s1, d0 is a reaction to fire class under BS EN 13501-1. Classes run from A1, the best, down to F. The s figure grades smoke production from s1, the lowest, to s3. The d figure grades flaming droplets from d0, the lowest, to d2.

The class describes how the surface behaves in a fire. It says nothing about how long a wall lasts. Siniat declares A2-s1, d0 for both its GTEC Standard Board and its GTEC Fire Board, so the Euroclass alone will not tell a fire board from a standard one.

For wall and ceiling linings in a dwelling, Table 4.1 of Approved Document B Volume 1 asks for class C-s3, d2 in most rooms and D-s3, d2 in small rooms of up to 4 square metres. An A2-s1, d0 board meets both.

Type F is the BS EN 520 designation for gypsum plasterboard with improved core cohesion at high temperature. In plain words, the core holds together for longer once the gypsum is heated. Siniat describes the core of its GTEC Fire Board as gypsum with fillers and fibres.

BS EN 520 sets several types, and one board can carry more than one letter. Siniat declares its GTEC Fire Board as Type D and F, and its GTEC Standard Board as Type A.

• Type A: the letter Siniat declares for its general purpose standard board
• Type D: controlled density
• Type E: sheathing board
• Type F: improved core cohesion at high temperature
• Types H1, H2 and H3: reduced water absorption
• Type I: enhanced surface hardness

In Siniat's published partition data, one layer of 12.5mm Siniat Fire MR Board each side of a Siniat CS50 C stud is classified EI 30. One layer of 15mm Siniat Fire Board each side of the same stud is classified EI 60. Those results belong to the whole partition.

The same tables show why the system counts for more than the label on the board. Two layers of 12.5mm Siniat Standard Board, a Type A board, each side of that stud are also classified EI 60.

Siniat states that its figures apply to imperforate, jointed partitions built with its own studs, tracks, boards, screws and finishing products, installed to its guides, and that any alteration may impair them. A result for one manufacturer's system does not carry across to another manufacturer's board or stud.

Approved Document B Volume 1 covers dwellings in England. In a new-build house it asks for fire resisting construction around a protected stair, between an integral garage and the house, in walls between houses, and in the structure. Most of these are set at 30 minutes, with 60 minutes for walls between houses.

These are the guidance values. The fire strategy and specification for your scheme set what is built, and the manufacturer's tested detail sets how it is built. The rules differ in Scotland, Wales and Northern Ireland, and this guide covers England only.

The current edition on gov.uk is the 2019 edition incorporating the 2020, 2022, 2025 and 2026 amendments, collated with the 2029 amendments.

• Protected stair: REI 30 at all storeys where a house has a storey more than 4.5m above ground, with cavity barriers or an EI 30 ceiling above it (paragraph 2.5)
• Integral or attached garage: REI 30 from the garage side to the wall and any floor between garage and house, and an E 30 Sa self-closing door (paragraph 5.6 and Diagram 5.1)
• Semi-detached and terraced houses: every wall between the houses built as a compartment wall (paragraph 5.5), with a minimum of 60 minutes (Table B2)
• Structure, including floors: 30 minutes where the top floor is up to 5m above ground, and a minimum of 30 minutes in three storey houses (Table B2)
• Flats: every floor between flats and every wall separating a flat from another part of the building is a compartment floor or wall (paragraph 7.1)

A fire rated partition performs as tested only when it is built as tested. Approved Document B warns that small differences in fixing method, joints, dimensions, insulation and air gaps can significantly affect fire performance. On a housing site the faults that defeat a lining are usually simple ones.

Siniat's manual asks for services to be planned so that penetrations through rated partitions are kept to a minimum. It allows pipes of 40mm internal diameter or less to be sealed with its intumescent acoustic sealant, apart from cPVC pipes, and refers other openings to the fire stopping product supplier for installation and tested details.

• Standard board fixed where the specification calls for fire board, often from a mixed stack
• Screws at wider centres than the system allows. Siniat's single frame partitions call for 300mm
• A second layer left off, or joints not staggered between layers
• Pipes and cables through the wall left open, or sealed with an untested product
• Back boxes cut into a rated wall with no tested detail behind them
• Joints left unfilled where the system was tested jointed

Approved Document B gives fire resistance as European classes under BS EN 13501-2, and allows BS 476 results as an alternative for products lawfully on the market. The 2029 amendments remove that alternative from 2 September 2029. Approved Document B notes that the national and European classifications do not automatically equate.

The national classes for reaction to fire went first. The 2025 amendments removed them from 2 March 2025, and dropped BS 476 parts 6 and 7 from the document's list of standards.

Transition rules apply. The earlier guidance still applies where a building notice, initial notice or full plans application was made before 2 September 2029 and the work is sufficiently progressed, which for a new building means foundations or piling started, before that day or within six months of it.