Scaffolding for London House Extensions and Loft Conversions: What You Need, What It Costs, and the Highway Licence

**The most common scaffold configurations for London domestic construction (2025)**:

*1. Independent tied scaffold (tube-and-fitting or system scaffold)*:

• The independent tied scaffold is the most common type for London residential construction. It consists of a free-standing scaffold structure (independent of the building) that is tied to the building at regular intervals for stability:
• •**Standards** (vertical tubes) are set on base plates on the ground or on soleplates on the pavement
• •**Ledgers** (horizontal tubes running along the face of the building) are connected to the standards
• •**Transoms** (horizontal tubes running out from the building to the outer standards) support the boards (working platforms)
• •**Ties** (scaffold tubes or anchor bolts connecting the scaffold to the building wall) provide lateral stability — typically at every lift (every 2m vertically) and every third standard (every 4–6m horizontally)
• •**Bracing**: diagonal tubes within the scaffold to provide lateral and longitudinal stiffness

*Two main types of scaffold construction*:

| Type | Construction method | Advantages | Disadvantages | Typical London use | |---|---|---|---|---| | **Tube-and-fitting (traditional)** | Standard scaffold tubes (48.3mm OD; 3.2mm or 4.0mm wall; Grade S355 steel or BS EN 10255) connected with swivel and right-angle couplers (Kwikform; BRT system; ringlock) | Maximum flexibility — any configuration possible; can be adapted to irregular building shapes and tight London sites | Slower to erect; more connection points (more labour); heavier | Complex loft conversions; irregular buildings; confined sites where non-standard configurations are needed | | **System scaffold (Kwikstage; Haki; Layher Allround)** | Pre-engineered modular scaffold system using steel tubes with integral connectors (rosettes; wedge heads) at standard spacings | Faster erection; fewer connections; lighter; integral guardrails (improving safety); NASC-compliant more easily | Limited flexibility (works in set bay widths and lift heights); more expensive to hire per unit | Standard rear extensions; full scaffold around a standard 2–3 storey London terrace; the preferred choice for speed and safety compliance |

*2. Tower scaffold (mobile or static)*:

• A self-supporting tower on wheels (mobile) or fixed base (static), used for access to specific working areas where a full independent scaffold is not justified:
• •Typical height: 2–8m working height (SH)
• •PASMA (Prefabricated Access Suppliers' and Manufacturers' Association) standards — tower erectors should be PASMA-trained
• •Used for: painting and decorating; minor external repairs; low-level access for rooflights installation; access inside the building for ceiling works
• •Hire cost: £80–£250/week (self-hire); less relevant for external London extension work where full scaffold is required

*3. Birdcage scaffold*:

An internal scaffold filling the full volume of a room or space — used for high-ceilinged spaces where full platform access to the ceiling is needed. Not typical for standard London domestic extensions — relevant for church or commercial conversion projects.

*4. Cantilever and fan scaffold*:

Used where the scaffold cannot be founded at ground level (e.g. over a basement well; or where the base of the scaffold is inaccessible). More complex structurally and requires specialist design. Relevant for some London basement extension sites or sites with restricted ground access.

**Scaffold configuration for the most common London domestic projects**:

• *Single-storey rear extension (rear of a London terrace)*:
• •Scaffold required: a simple independent tied scaffold on the rear elevation — typically one or two lifts (2m per lift) to cover the height of the flat roof (eaves typically 2.5–3.5m above ground) and any work at eaves level
• •Bay width: typically covers the full width of the extension (plus some overhang on each side) plus the relevant portion of the main house rear wall (for the structural opening works at first-floor level)
• •Position: scaffold is typically erected entirely within the rear garden — no highway licence required unless the access for scaffold erection requires temporary use of the pavement
• •Duration: typically 8–14 weeks (erected at start of superstructure stage; struck when external works completed)

• *Loft conversion (dormer or hip-to-gable) — rear and side elevation*:
• •Scaffold required: a full scaffold covering the rear roof slope, any dormer, and the side elevation (for hip-to-gable or L-shaped dormer configurations)
• •Height: extends from the ground to above the ridge of the roof — typically 8–12m above ground for a three-storey London terrace
• •Bay width: the full width of the rear elevation; wrapping around the side elevation if required for a hip-to-gable conversion
• •Position: typically the scaffold standards are set in the rear garden (if the rear elevation is accessed from the rear) — avoiding the public highway. However, in many London terraces where the only access to the rear is through the house or a shared side passage, scaffold may need to be partially erected on the pavement or highway at the front — triggering the highway licence requirement
• •Duration: typically 10–18 weeks

• *Full front elevation scaffold (for re-roofing; front parapet repair; chimney works)*:
• •Scaffold required: full height scaffold on the front elevation of the terrace — erected on the public footway (pavement) in virtually all cases
• •**Highway licence (Section 169 Licence) ALWAYS required** for front elevation scaffold in London (see below)
• •Duration: typically 2–10 weeks depending on works scope

**The highway scaffolding licence — what it is and when it is required**:

• When scaffold is erected on or over a public highway (including the pavement / footway adjacent to a property), a scaffold licence must be obtained from the highway authority before the scaffold is erected. This is a legal requirement under:
• •**Section 169 of the Highways Act 1980** (licence to erect scaffolding in a highway)
• •**London Local Authorities Act 1995** (additional powers for London Boroughs)
• •**Street Works Act 1991** (coordination of works in the highway)

• *When is a highway scaffold licence required?*:
• •Whenever any part of the scaffold (standards; base plates; boards; fans; loading bays) is placed on or overhangs the public footway or road
• •This includes: scaffold base plates on the pavement; overhead ties projecting from the building over the footway; scaffold fans (overhead protection canopies) over the footway; loading bays on the kerb or road
• •For most London rear extensions where the scaffold is entirely within the rear garden: NO highway licence required
• •For front elevation scaffold; for scaffold where pavement is used for scaffold erection in terraces without side or rear access: highway licence required

• *Consequences of erecting scaffold on the highway without a licence*:
• •Fixed penalty notice issued by the London Borough
• •Instruction to immediately remove the scaffold
• •Civil liability for any injury or property damage caused by unlicensed scaffold on the highway
• •Potential criminal prosecution for persistent non-compliance

**The highway scaffold licence application process in London**:

In London, the highway licence is administered by the relevant London Borough (or by Transport for London where the highway is a TfL-managed road — typically the TLRN: Transport for London Road Network — the major arterial roads). The process:

• *Step 1 — Scaffold design*:
• Before the licence can be applied for, a scaffold design must be produced showing the proposed scaffold configuration, the extent of the highway affected, and any proposed pedestrian diversion or hoarding arrangements. The design must comply with:
• •**NASC TG20:21** (the National Access and Scaffolding Confederation's guide for tube-and-fitting scaffold — the definitive UK scaffold design document)
• •**BS EN 12811** (scaffold performance standards)
• •The London Borough's specific conditions (some Boroughs have local conditions beyond TG20)

For simple residential scaffold (single-elevation tube-and-fitting up to TG20 standard configurations), a NASC-compliant contractor can erect the scaffold under TG20 without a bespoke engineered design. For complex or non-standard configurations (cantilever; heavy loading; fan construction over trafficked road), a structural engineer must produce a bespoke scaffold design.

• *Step 2 — Highway licence application*:
• Applications are made to the London Borough's highway licencing department. Required information:
• •Property address
• •Description of the works (brief)
• •Proposed scaffold start date and end date (the licence is time-limited)
• •Scaffold design or layout plan (plan view showing extent of scaffold on highway)
• •Contractor RAMS (Risk Assessment and Method Statement)
• •Public liability insurance of the scaffold contractor: minimum £5m (most Boroughs require £5m–£10m public liability cover for scaffold on the highway)
• •Payment of the highway licence fee

*Highway licence fees in London (2025 — approximate; varies by Borough)*:

| London Borough | Highway scaffold licence fee (residential works; 3 months) | Deposit | Notes | |---|---|---|---| | Islington | £500–£800 | £500–£1,000 | Per 10m² of highway occupied; returnable deposit if damage | | Hackney | £400–£700 | £500 | Per scaffold | | Wandsworth | £300–£600 | £500 | | | Lambeth | £400–£700 | £500–£1,000 | | | Southwark | £500–£900 | £500–£1,000 | | | General London range | £300–£1,500 | £300–£1,500 | Significant variation by Borough; check the specific Borough's schedule of fees |

*Total highway licence cost (2025)*: allow £600–£2,000 for the licence fee + deposit for a standard London residential scaffold on the highway. The deposit is refundable on licence expiry if the highway is left in good condition.

*Processing time*: allow 2–4 weeks from application submission to licence issue for most London Boroughs. Some Boroughs offer a fast-track process for an additional fee. Do not erect scaffold before the licence is issued — erecting without a licence has the consequences described above.

*TfL TLRN roads*: where the property fronts a TfL-managed road (A-roads on the TLRN — e.g. A1; A10; A2; A3; A4; A13; A23; A40 and their inner London sections), the highway licence is issued by Transport for London (not the London Borough). TfL processing times can be longer — allow 3–6 weeks.

**Scaffold design and safety requirements**:

• *NASC TG20:21 compliance*:
• NASC TG20 is the definitive guide for the design of general access scaffolds using tube and coupler systems in the UK. Key TG20 requirements relevant to London residential scaffold:
• •Boards: minimum 38mm thickness (47mm for heavy duty); grain-graded; tested to BS 2482; inspected before use
• •Guardrails: at least 950mm above the working platform (top rail); intermediate guardrail at 470mm; toe board at 150mm
• •Working platform width: minimum 4 boards (600mm) for light duty; 5 boards (750mm) for general construction; 6 boards (900mm) for heavy duty brick/block
• •Tie spacing: vertical maximum 4m; horizontal maximum 6m for independent scaffold (exact spacing from TG20 tables based on scaffold height and board width)
• •Inspection: scaffolding must be inspected: before first use; after modification; after any event likely to affect stability; at 7-day intervals. Inspections must be recorded in writing

• *Work at Height Regulations 2005*:
• All work at height in construction is governed by these regulations. Key requirements:
• •All scaffold must be erected, altered, and dismantled by a competent person (typically a CISRS-carded scaffold operative)
• •Pre-use inspection before each working shift (visual check; record of inspection)
• •Weather: scaffold must not be used in winds exceeding the design wind speed for the configuration (TG20 provides safe working wind speed guidance); in practice, scaffold operatives judge site conditions

**Scaffold programme integration and costs (London 2025)**:

*Typical scaffold hire durations and costs for London residential projects*:

| Project type | Scaffold configuration | Typical hire duration | Typical cost (hire only; all-in erect/strike) | |---|---|---|---| | Single-storey rear extension (rear garden only; no highway) | 1–2 lifts; rear elevation; in garden | 8–14 weeks | £900–£1,800 | | Rear extension with roof works + access to rear of existing house | 2 lifts; rear and part side | 10–16 weeks | £1,200–£2,500 | | Loft conversion — Velux only (rear elevation) | 2–3 lifts; rear elevation; pitched roof access | 8–14 weeks | £1,200–£2,200 | | Loft conversion — rear dormer | 3 lifts; rear elevation + dormer area | 10–16 weeks | £1,500–£3,000 | | Loft conversion — hip-to-gable | 3–4 lifts; full rear + side elevation | 12–20 weeks | £2,000–£4,000 | | Front elevation scaffold (re-roofing; parapet; chimney) — with highway licence | 3–4 lifts; front elevation on footway | 3–8 weeks | £1,500–£3,500 (plus £600–£2,000 highway licence) | | Full wrap-around scaffold (front + rear + side) — for major refurbishment | Full perimeter; multi-lift | 16–30 weeks | £3,500–£8,000 (plus highway licence if front) |

*Note*: scaffold costs in London are significantly higher than national averages due to access constraints; licensing requirements; higher labour costs; and the difficulty of erecting in confined rear gardens with limited vehicle access. All-in costs include erection; hire period; weekly inspections; and dismantling.

**Integrating scaffold into the extension programme**:

Scaffold is typically needed in two phases for a London loft conversion or extension:

*Phase 1 — Main works scaffold*: erected at the start of superstructure works (before the structural opening is formed; before roof works begin); remains in place throughout the external and roof construction; typically struck when the external envelope is watertight and all external works are complete.

*Phase 2 — Decoration/clean-up scaffold* (sometimes): a reduced scaffold configuration may be required for the second-fix external stage — for example, to point brickwork; seal junctions at the top of the extension; or install fascia and guttering at height after the main scaffold is struck. This may be avoided if all external works are completed during Phase 1.

*Scaffold erection sequence*: 1. Scaffold contractor visits site and confirms configuration with the principal contractor 2. Highway licence obtained from the Borough (if highway access required — allow 2–4 weeks; apply early) 3. Scaffold erected (typically 1–2 days for a residential extension scaffold; 2–4 days for a complex loft conversion scaffold) 4. Building Control notified of commencement (required within 48 hours of scaffold erection and start of works in some LPAs) 5. Weekly scaffold inspection carried out by a CISRS-qualified person; results recorded 6. Scaffold struck (typically 1 day for a residential extension scaffold) 7. Highway licence returned; deposit recovered from Borough (if highway used)

**Access constraints — the biggest challenge for London scaffold**:

London's densely built Victorian and Edwardian housing stock creates significant access challenges for scaffolding:

• *No rear access (the most common London scenario)*:
• Many London Victorian terraces have no side passage and no rear lane — the only access to the rear garden is through the house. In this case:
• •Scaffold materials must be carried through the house (covered floor protection is essential — Correx boards; protective carpet)
• •Scaffolding tubes (6.4m long standard lengths) must fit through the house (front door; hall; rear reception room; through the existing back addition). If the staircase is tight, scaffold may need to be cut (shorter sections — more connections required; more labour; slightly higher cost)
• •Some inner London sites require scaffold tubes and boards to be delivered by smaller vehicles (transit-sized; not full HGV) — confirm access constraints with the scaffold contractor before ordering

*Shared driveways and shared access*: Where a scaffold would block a shared driveway or access route shared with a neighbour, the neighbour's agreement should be obtained. If the shared access is the only means of access to the neighbour's property, the scaffold must include a clear pedestrian access route maintained throughout the hire period (or the scaffold is arranged to avoid blocking the route).

• *Neighbour notification*:
• While there is no legal requirement to notify neighbours before erecting scaffold (unless it involves the party wall or the public highway), good practice in London is to notify adjacent neighbours 1–2 weeks before scaffold erection — particularly where:
• •The scaffold will overlook or partially overshadow the neighbour's garden
• •The scaffold erection will create noise early in the morning or late in the afternoon
• •The scaffold tie points will be fixed into the shared party wall (which may require consent under the Party Wall Act — confirm with the party wall surveyor whether ties into the party wall are covered by the Party Wall Award or require additional consent)

**Scaffold and the party wall — party wall surveyor coordination**:

• Where scaffold ties are required through a shared party wall (a common requirement in London terraced house extensions), the party wall surveyor must be made aware of the scaffold design during the Party Wall Award process. The Party Wall Award typically includes:
• •A right of access for the scaffold contractor to erect and maintain the scaffold on the neighbour's side of the party wall (if required)
• •Conditions on the repair of any tie holes after scaffold is struck (typically made good with matching mortar)
• •Photographic schedule of condition of the neighbour's property before scaffold erection commences (to protect against unfounded damage claims during and after the works)

Confirm with the party wall surveyor that the scaffold configuration is covered by the Award before erection commences — if ties through the party wall were not covered in the Award, a further notice or agreement may be required.