Second fix: what good looks like

600 mm

Appliance space, general storage, and unit installation

Design specifications should account for standard appliance depths, typically 600mm, even if appliances are not supplied

Ceiling mounted at least 300 mm from any wall and 1–3 m horizontally from the appliance, or wall mounted above the height of any door or window and at least 150 mm from the ceiling

Carbon monoxide alarm position

Room containing a fixed combustion appliance

520 mm

Cistern access requirements

Adequate access must be provided to cold water storage cisterns located in roof spaces and voids, through an opening of at least 520mm in each direction

0.33 m² clear openable area, at least 450 mm in both height and width, with the bottom of the opening 800–1100 mm above floor level

Clear opening of an escape window

First floor and loft rooms served by an escape window

750 mm from a corridor at least 900 mm wide; 775 mm from a 825 mm corridor; 900 mm from a 750 mm corridor

Clear opening width of an internal door

Internal doorway on the entrance storey of a dwelling

6 °C

Conditions for Pipe Freezing Calculations

Calculations for pipe insulation to prevent freezing are based on specific assumed conditions, typically including an external air temperature of -6°C and an internal water temperature of +7°C

Below 800 mm from floor level in walls and partitions; below 1500 mm in doors and in side panels within 300 mm of a door edge

Critical locations for safety glazing

Internal and external glazing in a dwelling

10 mm

Door Clearances and Fire Door Installation

Internal doors, including fire doors, must be installed with sufficient clearance from the finished floor level to accommodate flooring, typically around 10mm for non-fire doors

400 mm

Door swing clearance at stair landings

door swings on or near landings do not impede safe passage, particularly verifying the 400mm minimum clearance from the first tread on private stair bottom landings.

300 mm

Electrical Accessory Clearance Elevation Detail

Elevation diagrams specify the minimum 300mm horizontal separation required between electrical accessories and the edges of sinks or wash basins

300 mm

Electrical Accessory Clearance from Water Diagrams

Diagrams illustrating the required 300mm minimum horizontal clearance for electrical accessories from water sources, such as sinks and wash basins, are commonly used in guidance documents

300 mm

Electrical socket outlet distance from water source

all socket-outlets are located at least 300mm horizontally from the edge of any sink or basin.

150 mm

Flue pipe horizontal run limit

A short horizontal section, typically up to 150mm in length, is permitted within a flue pipe system to connect a back-outlet liquid fuel appliance to the main flue, provided the primary run remains as vertical as possible.

Measured at the centre of the flight; at least 50 mm at the narrow end

Going of a tapered tread

Winder or tapered tread in a private stair

900 mm to stair flights; 1100 mm to landings, balconies and external edges

Guarding height in a dwelling

Single-family dwelling

900–1000 mm above the pitch line or floor

Handrail height on a stair or ramp

Private stair, landing or ramp in a dwelling

600 mm

Handrails for Tapered Treads and Winders

For stairs incorporating tapered treads or winders, any handrail provided on the outside of the turn must offer a safe handhold for the full rise of the stair, particularly if the total rise exceeds 600mm

225 mm

Hearth Provision and Floor Finishes

A hearth may not be necessary if an appliance's flame or incandescent material is positioned at least 225mm above the floor

12 mm

Hearth Thickness for Appliances

Hearths for appliances, other than specific solid fuel or gas-specific cases, must be constructed from non-combustible materials with a minimum thickness of 12mm.

Kitchen 30 l/s next to the hob or 60 l/s elsewhere; utility room 30 l/s; bathroom 15 l/s; WC 6 l/s

Intermittent extract rates by room

Intermittent mechanical extract in a wet room

At least equal to the least width of the flight, kept clear of door swings

Landing length at the top and bottom of a flight

Landing at the head or foot of a private stair

No opening should allow a 100 mm sphere to pass

Maximum gap in guarding

Guarding to a stair, landing, balcony or floor edge in a dwelling

48 °C

Maximum hot water temperature at a bath

Hot water supply to a fixed bath in a dwelling

Rise 155–220 mm, going at least 220 mm, maximum pitch 42°, and twice the rise plus the going between 550 mm and 700 mm

Private stair rise, going and pitch

Private stair within a single dwelling

One twentieth (1/20) of the floor area of the room for a hinged or pivot window opening 30° or more

Purge ventilation opening area

Habitable room ventilated by openable windows

25 mm

Soundproofing Measures for Soil Pipes

Sound insulation for soil pipes involves either encasing them in boxing made from a material with a minimum mass of 15kg/m², or wrapping them with at least 25mm of unfaced mineral wool, typically 10kg/m³ density

600 mm

Stair Handrail Height and Clearance

A handrail is mandatory for flights of stairs where the rise exceeds 600mm

600 mm

Staircase guarding requirements

Staircases and landings require adequate guarding where there is a drop of more than 600mm

16 mm

Tread overlap for open-riser stairs

For stairs with open risers, each tread must overlap the one below by a minimum of 16mm, or 15mm in Scotland, to meet safety requirements and prevent foot entrapment.

75 mm for baths, basins, sinks and showers on a branch; 50 mm for a WC trap

Water seal depth at appliance traps

Appliance trap on a branch discharge pipe