Pre-Demolition Audit: Structural Survey, Services Disconnection, Hazardous Material Survey and Waste Audit

Summary

The pre-demolition audit forms the evidential foundation for the entire demolition project. It provides the information needed to plan a safe demolition sequence, comply with CDM 2015 pre-construction information duties, manage hazardous materials legally, and estimate waste disposal costs accurately. It is not optional — without a complete pre-demolition audit, a competent demolition contractor cannot prepare a safe method statement or comply with their legal obligations under asbestos, CDM and waste regulations.

The audit encompasses four main components: hazardous materials surveying (led by asbestos but potentially including other hazardous substances), structural condition assessment, verification that all utility services have been disconnected or made safe, and a waste audit to characterise the volume and nature of demolition arisings. These surveys are usually commissioned by the client or Principal Designer, but where the client has not arranged them, the Principal Contractor must raise this as a pre-condition of commencing work.

In practice, the pre-demolition audit can take anywhere from a few days for a simple domestic structure to several weeks for a large commercial or industrial building. On contaminated industrial sites, specialist environmental surveys may also be required before demolition begins. The audit should be completed before the Construction Phase Plan is finalised, because the CPP must address hazards identified in the surveys.

Key Facts

• R&D Survey legal requirement — a Refurbishment and Demolition Survey must be undertaken before any demolition work commences; this is a legal requirement under Regulation 7 of the Control of Asbestos Regulations 2012
• R&D vs Management Survey — a Management Survey identifies asbestos for ongoing management in occupied buildings; an R&D Survey is more intrusive and must identify all asbestos before it is disturbed by demolition; they are not interchangeable
• UKAS accreditation — asbestos surveys for demolition purposes must be carried out by a UKAS-accredited surveyor (to ISO 17020); check the UKAS online database before instructing a surveyor
• Structural survey requirement — there is no single regulation mandating a structural survey, but CDM 2015 requires adequate pre-construction information and HSE guidance makes clear that structural assessment is required for demolition projects
• Services disconnection — all live services (gas, electricity, water, drainage, telecommunications, district heating) must be confirmed disconnected before demolition commences; certificates from the relevant utility or network operator are required
• Gas disconnection — carried out by the gas network operator (Cadent, SGN, Northern Gas Networks, Wales & West Utilities depending on region), not by a Gas Safe registered installer; connection to the gas main must be cut off and capped at the main
• Electricity disconnection — carried out by the Distribution Network Operator (DNO), not by an NICEIC/NAPIT registered electrician; the meter is removed and the supply cut at the street service pillar or substation
• Waste audit — an assessment of the volume and type of materials arising from demolition; required to complete waste documentation under the Environmental Permitting (England and Wales) Regulations 2016 and to identify any hazardous waste requiring specialist disposal
• Hazardous waste documentation — all producers of hazardous waste must complete a Hazardous Waste Consignment Note (HWCN) for each consignment under the Hazardous Waste (England and Wales) Regulations 2005 (as amended); hazardous waste streams must not be mixed
• Salvage assessment — part of the waste audit should identify materials with reuse or recycling value; stripping out salvageable materials before demolition reduces disposal costs and supports waste hierarchy compliance
• Contaminated land — where a site has a history of industrial use, contaminated land assessment (Phase 1 and potentially Phase 2) may be required before or alongside demolition
• Historic building recording — for listed buildings or structures of historic interest, Historic England or the local planning authority may require photographic or measured survey recording before demolition
• Lead paint — buildings constructed before the widespread removal of lead from paint (broadly pre-1970s, though some paints contained lead until later) should be assessed for lead paint as part of the hazardous materials survey
• Structural drawings — the client should provide any available structural drawings, including original engineering calculations; absence of drawings increases structural survey scope and cost

Quick Reference Table

Detailed Guidance

Asbestos Refurbishment and Demolition Survey

The R&D Survey is the most critical element of the pre-demolition audit. Asbestos-containing materials (ACMs) are present in a very high proportion of buildings constructed or refurbished before 2000, and in some materials used after that date. Disturbing ACMs during demolition without proper controls is a criminal offence and creates serious long-term health risks for workers and the public.

The R&D Survey must be intrusive — surveyors will break into the structure, including removing floor coverings, opening ceiling voids, breaking into walls, lifting roof materials, and accessing plant rooms. The level of intrusion required means the building must be vacated and, in some cases, partially stripped out before the survey can be completed. This is a significant project planning consideration: you cannot carry out a full R&D Survey on an occupied building without special arrangements.

The survey report must identify the location, type and condition of all ACMs found, together with a sample analysis confirming the presence and type of asbestos (chrysotile, amosite, crocidolite, etc.). The report should provide an asbestos register that can be used to plan the asbestos removal programme.

Before demolition commences, all identified ACMs must either be removed by a licensed asbestos removal contractor (for licence-notifiable materials — any material containing amosite or crocidolite, and all sprayed asbestos and asbestos insulation regardless of type) or, in limited cases, managed in place where removal is not reasonably practicable and the demolition method ensures no fibre release. In practice, for full demolition, all ACMs should be removed before demolition begins.

Licensed asbestos removal must be notified to the HSE at least 14 days before work starts (with some exceptions allowing shorter notice). The asbestos removal contractor must hold a current HSE asbestos removal licence.

Structural Survey for Demolition Planning

A structural survey for demolition purposes is different from a homebuyer's survey or a standard condition survey. The demolition structural survey aims to answer a specific question: is this structure safe to demolish in the proposed sequence, and what temporary works or propping is required to prevent unplanned collapse?

Key elements of a demolition structural survey include:

Structural form assessment — identifying the load-bearing elements (columns, beams, walls, floor slabs), the construction materials, and the structural system. This is essential for planning the demolition sequence to avoid removing structural elements that are supporting others.

Condition assessment — identifying deterioration, previous alteration or damage that may affect structural stability. A building that has been modified or extended without formal structural design may have load paths different from those shown on original drawings.

Foundation assessment — particularly important where adjacent structures are to be retained. The structural engineer must assess foundation type, depth, and condition, and consider the effect of demolition on neighbouring foundations.

Temporary works requirements — the structural survey should identify where temporary propping, shoring or other temporary works will be required to maintain stability during the demolition sequence. Temporary works must be designed by a competent engineer (see BS 5975 [verify] for temporary works design).

Structural drawings review — the engineer will review any available original structural drawings. Where drawings are absent or incomplete, the survey must rely on physical investigation, which increases cost and time.

The structural survey report should be provided to the Principal Contractor before the method statement is prepared. The method statement must reflect the sequence recommended by the structural engineer.

Services Disconnection: A Common Source of Delays

Services disconnection is frequently the longest lead-time item in the pre-demolition programme, yet it is often the last thing contractors consider. Utility operators are not always responsive, and the disconnection process requires coordination with their works management systems.

Gas disconnection requires the gas network operator to physically cut and cap the supply at the main. The process begins with contacting the network operator's disconnection team. They will visit the site to assess the connection, quote for the work, and schedule it. This process typically takes four to eight weeks from initial contact. On complex sites with multiple meters or industrial supplies, it can take longer. A Gas Safe registered engineer can isolate and make safe internal pipework, but cannot cap the main — this is exclusively the network operator's responsibility.

Electricity disconnection follows a similar process with the Distribution Network Operator. The DNO will remove the meter and cut the supply. For three-phase industrial supplies or substations, the process is more complex and may involve decommissioning of on-site electrical infrastructure. Energy suppliers and DNOs are different organisations — contact the DNO, not just the energy supplier.

Water and drainage are managed by the local water company (supply) and sewerage undertaker (drainage). Disconnection of the water supply at the communication pipe is carried out by the water company. Drainage connections require a drain survey to confirm connection points and then disconnection by agreement with the sewerage undertaker. In some cases, drains on the site may serve neighbouring properties — this must be identified before demolition.

Telecommunications — multiple providers may have installations in the building, including openreach ducts, broadband infrastructure, and private circuits. Contact each relevant operator; BT Openreach is typically the primary network owner.

Keep all disconnection certificates on file. A Principal Contractor who proceeds with demolition before receiving written confirmation of disconnection from each utility is exposed to significant liability if a gas explosion, electrocution or flooding incident occurs.

Waste Audit and Waste Management Planning

The waste audit serves two purposes: it quantifies the volume and type of demolition arisings for cost and logistics planning, and it characterises materials to ensure they are managed within the legal waste framework.

Under the duty of care provisions of the Environmental Protection Act 1990, anyone producing, carrying, or receiving controlled waste (which includes demolition waste) has legal obligations. Demolition contractors must:

• Ensure waste is only transferred to licensed waste carriers
• Complete and retain waste transfer notes for non-hazardous waste
• Complete hazardous waste consignment notes for hazardous materials
• Retain all waste documentation for a minimum of two years (three years for hazardous waste consignment notes)

The waste audit should categorise materials under the appropriate European Waste Catalogue (EWC) codes. Common demolition waste codes include concrete, bricks, tiles and ceramics (17 01 series), wood (17 02 01), glass (17 02 02), metals (17 04 series), and mixed demolition waste (17 09 04). ACMs have specific EWC codes depending on their asbestos content.

The waste hierarchy — prevent, prepare for reuse, recycle, other recovery, dispose — applies to demolition waste. Soft strip programmes (removing intact salvageable materials before demolition) can significantly reduce disposal costs and environmental impact. Brick, stone, structural timber, sanitary ware, architectural metalwork and roofing slates all have reuse markets.

Pre-treatment of demolition waste on-site (e.g., crushing concrete for aggregate) may require an Environmental Permit or may qualify for a standard rules permit or exemption, depending on the volume and output specification. Check with the Environment Agency (or Natural Resources Wales, SEPA, or NIEA depending on location) before operating any on-site treatment.

Frequently Asked Questions

Who commissions and pays for the pre-demolition audit surveys?

Under CDM 2015, the duty to provide pre-construction information sits with the client. In practice, the client often commissions the R&D asbestos survey and structural survey, with costs varying widely depending on building size and complexity. However, if the client has not arranged these surveys, the Principal Contractor must not commence work — the PC should make this a condition precedent in their contract. For domestic clients who may not be aware of their obligations, the demolition contractor should explain what surveys are required before tendering.

Can demolition start before all services are disconnected?

No. All live services must be confirmed disconnected before any structural demolition commences. Internal service isolation (turning off at the meter, capping internal pipes) is not sufficient — the supply must be cut at the main by the relevant network operator. The only exception in practice is where some services cannot be disconnected due to their connection to neighbouring occupied properties, in which case a specific plan for working around live services must be agreed with the network operator, the Principal Contractor, and reflected in the method statement.

What if asbestos is found during demolition that was not in the R&D Survey?

Stop work in the affected area immediately. Do not disturb the material further. Inform the site supervisor and the asbestos removal contractor. Have the material sampled and analysed before work resumes. This situation can indicate that the R&D Survey was inadequate — the UKAS-accredited surveyor may have liability. Regardless of the cause, the discovery must be managed correctly under the Control of Asbestos Regulations 2012. Document the discovery, the response, and the sample results.

How long does a waste audit take?

A basic waste audit for a typical domestic or small commercial structure can be completed alongside the structural survey in a day or two. Large industrial sites with significant quantities of materials, potential contamination, or complex plant and equipment may require a week or more. The waste audit is often the least expensive of the pre-demolition surveys but provides essential cost information for disposal budgeting.

Is a Phase 2 contaminated land survey always required for brownfield demolition sites?

Not always. A Phase 1 desktop study and walkover survey (reviewing historical land use records, maps, and site inspection) is the starting point. If the Phase 1 concludes there is no significant risk of contamination, a Phase 2 (which involves intrusive investigation — trial pits, boreholes, and sampling) may not be required. However, for sites with a history of industrial use (former factories, petrol stations, dry cleaners, printing works, etc.), a Phase 2 is almost always warranted. The local planning authority or Environment Agency may specify requirements as planning conditions.

Regulations & Standards

• Control of Asbestos Regulations 2012 — Regulation 7 covers the duty not to carry out work likely to disturb asbestos without proper assessment and survey; Regulation 11 covers the licence requirement for licensed asbestos removal; Regulation 8 covers notification of licensed work to the HSE

• Construction (Design and Management) Regulations 2015 — places the obligation for pre-construction information on the client; Principal Designer and Principal Contractor must ensure information is adequate

• Environmental Protection Act 1990 — waste duty of care applies to all parties handling demolition waste

• Environmental Permitting (England and Wales) Regulations 2016 — covers on-site waste treatment, waste carrier registration, and hazardous waste consignment note requirements

• Hazardous Waste (England and Wales) Regulations 2005 (as amended) — requires a Hazardous Waste Consignment Note for each hazardous waste consignment; prohibits mixing of hazardous waste streams

• Health and Safety at Work etc. Act 1974 — general duty to ensure safe systems of work; underpins the requirement for structural surveys

• HSE — Asbestos: The Survey Guide — HSE's guidance on asbestos surveying including R&D surveys [verify availability]

• UKAS Accredited Asbestos Surveyors — search for UKAS-accredited surveying organisations

• Environment Agency — Hazardous Waste — guidance on hazardous waste disposal including asbestos

• HSE — Control of Asbestos — comprehensive HSE asbestos guidance

• NFDC — NFDC technical guidance on pre-demolition surveys

• cdm regs demolition projects — CDM duties and pre-construction information obligations

• nfdc membership and standards — Competency requirements for demolition contractors

• structural demolition sequence — Using structural survey findings to plan the demolition sequence

• demolition adjacent structures — Additional survey requirements where demolition is adjacent to occupied structures