Building Regulations for Internal Glazing

Do you need Building Regulations approval for internal glazing?

Most internal glazing does not need a Building Regulations application on its own, but it must still meet the Regulations. In England, the key rules are in Approved Document K: glass in "critical locations" — low down in walls and in and around doors — must be safety glass. You need Building Control involvement when the work goes further, such as cutting a new opening in a load-bearing wall or putting glass into a fire escape route.

What is a critical location?

Approved Document K identifies the places where people are most likely to walk into glass or fall against it:

any glazing in an internal or external wall or partition between the finished floor and 800mm above it;
any glazing in a door, or in a side panel within 300mm of either edge of a door, between the finished floor and 1500mm above it.

In those zones the glass has to break safely (toughened or laminated safety glass, classified under BS EN 12600), be robust enough not to break, or be in small panes within set limits. In practice, almost every internal screen, partition and glazed door falls into a critical location somewhere — which is why we use toughened or laminated safety glass throughout, not just where it is strictly required.

Toughened or laminated — which safety glass?

Toughened glass (BS EN 12150) is several times stronger than ordinary glass and breaks into small, blunt pieces. Laminated glass (BS EN 14449) has a plastic interlayer that holds the pieces in place if it breaks, and it also cuts sound better. Frameless partitions and screens usually use toughened glass; balustrades and overhead glass usually use laminated toughened glass so the panel stays in place even if it is damaged.

Does glass in an office need markings?

Yes, in most cases. In buildings other than dwellings, Approved Document K asks for large areas of clear glass that people could walk into to be marked so they are visible. The usual approach is a band or pattern in two zones: 850mm to 1000mm and 1400mm to 1600mm above the floor. The Workplace (Health, Safety and Welfare) Regulations 1992 also require transparent surfaces in workplaces to be marked where needed for safety. Our manifestation service covers plain bands, dots and branded designs that meet both.

When does internal glass need to be fire-rated?

Fire safety is covered by Approved Document B. Standard toughened glass is not fire-resisting, so glass that forms part of an escape route has to be a tested fire-rated system. Common examples:

Loft conversions. Adding a floor to a two-storey house usually means the stairway must become a protected route to the front door, so glazed doors or screens onto the hallway and landing may need to be fire-resisting.
Flats. Glass between the entrance hall and living spaces can be part of the protected route out of the flat.
Offices and commercial buildings. Glass beside escape corridors and stairs, and in some compartment walls, must hold back fire for a set time.

Fire-rated glass is described by what it resists: integrity (E) stops flames and smoke passing through; integrity and insulation (EI) also limits the heat that passes through. Ratings such as E30 or EI30 give the minutes. The rating belongs to the whole tested system — frame, glass, seals and fixings — so a fire-rated screen has to be built exactly as tested. See our fire-rated glazed screens page.

Do I need Building Control if I remove a wall?

Yes, if the wall is load-bearing. Forming or widening an opening in a load-bearing wall is structural work under Part A and needs Building Control approval, usually with a structural engineer's calculation for a lintel or steel beam. Non-load-bearing stud walls can normally be removed without an application, but check with a builder or engineer if you aren't sure which you have. We fit glazing into the finished opening, and can work alongside your builder.

What about balustrades and glass on stairs?

Guarding on stairs, landings and the edges of internal floors must be high enough and strong enough to stop people falling. In a house, internal stairs and landings need guarding at least 900mm high; in other buildings, landings and floor edges generally need 1100mm. Glass balustrades are designed to the loadings in BS 6180, and we use laminated toughened glass so a damaged panel stays in place.

Listed buildings, leases and conservation areas

Internal changes to a listed building can need listed building consent, even with no Building Regulations application — and carrying out work without consent is an offence. Your local authority's conservation officer can advise. Conservation-area status doesn't usually affect internal work. If you own a leasehold flat, your lease will often require the freeholder's consent before layouts are altered.

Scotland, Wales and Northern Ireland

The rules above are for England. Wales publishes its own versions of the Approved Documents, Scotland uses the Building Standards technical handbooks, and Northern Ireland uses its Technical Booklets, including one on glazing. The principles — safety glass in risky locations, markings on large glass areas, fire-rated glass on escape routes — are the same, and we work to the version that applies where you are.

This guide is general information, not a substitute for advice from Building Control or a fire engineer on a specific project. At survey we flag anything that needs an application or consent before you commit.

Building Regulations for internal glazing: a plain-English guide