The material inventory in a pre-redevelopment audit

The material inventory is the part of a pre-redevelopment audit that says what is physically in the building, in what quantity, in what condition, and what could be done with it other than crushing it. It is compiled before demolition, from survey rather than from assumption, and it is the evidence base for every reuse claim the scheme later makes. Get it wrong and the circular economy commitments in the application are numbers nobody can stand behind.

It is not a site waste management plan. That document deals with waste arising during construction. The audit looks backwards at what already exists.

What the audit records before demolition

A pre-redevelopment audit sets out the existing building's materials and components, quantified, with an assessment of the potential for reuse, recycling and recovery. It informs the demolition specification, the circular economy narrative and the whole life carbon assessment.

The inventory itself has four columns of substance: what the material or component is, how much of it there is, what condition it is in, and what the realistic destination is. Everything else in the audit hangs off those four.

Scope the audit to the whole of what is being removed. That means the superstructure, the substructure where it will be broken out, the facade, internal finishes, fit-out, mechanical and electrical plant, external works, and any hardstanding or retaining structures. Partial audits that cover the building but not the site works produce reuse percentages that fall apart when the figures are checked later.

Surveying materials, quantities and condition

Quantities come from measurement, not from a drawing take-off alone, because as-built rarely matches as-drawn on a building of any age.

The practical method is a combination: drawn take-off where record drawings exist and are reliable, intrusive opening up at sample locations to confirm build-ups, and physical measurement on site. Quantities are usually expressed by mass in tonnes, since that is the unit waste is measured in and reported against, with volumes and unit counts alongside for components such as doors, radiators and light fittings.

Condition grading needs a stated scale and a stated assessor. Something as simple as good, serviceable, damaged and unsalvageable works, provided the criteria are written down and applied consistently. Add the fixing method, because a brick laid in lime mortar is recoverable whole while the same brick in cement mortar usually is not, and a bolted steel frame can be dismantled where a welded one cannot.

Photograph everything and reference the photographs to a floor plan. The auditor who returns in eighteen months to defend a figure will need them.

Identifying elements with reuse value

Not everything worth recovering is worth recovering economically, and the audit should say which is which.

Three things convert potential into actual reuse. A destination, meaning a named receiver or a place in the new scheme. A programme allowance for careful dismantling, which takes longer than demolition. And storage, which is the constraint nobody budgets for on a tight urban site.

Where structural steel is proposed for reuse, remember that it needs traceability and testing to be used structurally again. Saying it will be reused without addressing that is the sort of claim a reviewer will mark down.

Hazardous materials and the separate asbestos survey

The material inventory is not an asbestos survey, and conflating them is a safety problem rather than a paperwork one.

A refurbishment and demolition asbestos survey is required under the Control of Asbestos Regulations 2012 before demolition or major refurbishment, carried out by a competent surveyor to the recognised methodology, and it is intrusive by design. Its outputs feed the inventory, but it is a separate commission with separate competence requirements and it should be programmed as one.

Other hazardous or problematic materials belong in the inventory with their own handling notes: lead paint and lead pipework, ozone-depleting refrigerants in chillers and cold stores, polychlorinated biphenyls in older transformers and capacitors, fluorescent tubes and discharge lamps, gypsum requiring separate disposal, treated timber, and fuel or chemical residues in tanks. Each changes the demolition method and the cost, and each has its own waste classification.

Routes to reuse, recycling and disposal

Assign every quantified item a destination on the waste hierarchy in the Waste (England and Wales) Regulations 2011, in this order.

1. Retained in situ, where the element stays in the redeveloped building.
2. Reused on site, where it is recovered and incorporated into the new scheme.
3. Reused off site, where it goes to another project or a reclamation market.
4. Recycled, where the material is reprocessed, such as concrete crushed to aggregate.
5. Other recovery, including energy recovery.
6. Disposal, which is the residual.

Retention in situ is where the carbon saving is largest and where it is most often overlooked. A substructure or a frame that can be kept changes the whole scheme's carbon position far more than any amount of brick reclamation, and the audit is the document that establishes whether it is feasible. That argument belongs alongside the demolition case rather than after it, and where ground conditions govern whether a substructure can stay, it runs into the same evidence covered in the ground gas section of a contaminated land assessment.

Record the assumed destination and the evidence for it. "Reused off site" with no receiver named is an aspiration, and reviewers increasingly treat it as one.

Feeding the audit into the demolition specification

An audit that does not change the demolition contract has achieved nothing.

The inventory should translate into specification clauses: elements to be removed by careful dismantling rather than mechanical demolition, the sequence required to recover them, protection and storage requirements, segregation arrangements on site, and the records the contractor must keep. Where dismantling extends the programme, that has to be priced and accepted at tender rather than negotiated afterwards.

Contract structure matters too. A demolition contractor who owns the arisings has an incentive to recover what has value and no incentive to recover what does not. Where the scheme has committed to a reuse figure for planning purposes, that commitment needs to sit in the contract with a reporting obligation attached.

Reporting so the figures can be checked afterwards

Present the inventory so a third party can audit it, because on a scheme with a circular economy condition someone will.

Give the survey date, the surveyor and their competence, the method for each quantity, the condition scale and the assumptions made. Tabulate by element and by material, with mass in tonnes, the destination assigned and the evidence for it. State the totals, the percentage by mass assigned to each tier of the hierarchy, and the exclusions.

Then commit to reporting actuals after demolition against those predictions, with waste transfer notes and weighbridge tickets as the evidence. That closing loop is what distinguishes a document written for validation from one written to be used, and it is the same discipline that makes the waste stream section of a site waste management plan worth having.

Browse the 66 report types on PlanScope to see how a pre-redevelopment audit sits against the carbon, waste and demolition evidence a major scheme carries.

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