Pre-demolition audits and honest reuse targets
A pre-demolition audit is a quantified inventory, not a statement of intent. Here is what it records and how to set targets you can still stand behind at completion.
A pre-demolition audit is a quantified inventory of what is already on the site, material by material, with a reuse route identified for each. It is the evidence base for every reuse target that follows, and a circular economy statement built without one is a set of aspirations with no arithmetic behind it. Officers in authorities that take this seriously, London boroughs in particular, have become good at spotting the difference.
The discipline is simple to describe and tedious to carry out, which is why it is usually done badly. Get the audit right and the targets write themselves.
What a pre-demolition audit records
The audit covers the existing buildings, the hardstanding, the fixed plant and the ground. For each element it needs a quantity, a condition assessment and a destination.
| Element | What to record | Why it matters |
|---|---|---|
| Structural frame | Material, member sizes, tonnage, connection type, available documentation | Steel and timber reuse depends on traceability and on bolted rather than welded connections |
| Concrete and masonry | Volume in m3, tonnage, reinforcement content, contamination | The largest volume by mass, and the main on-site reuse opportunity as crushed aggregate |
| Facade | Cladding type, glazing units, stone or brick, fixing method | Demountable facades have reuse value, bonded assemblies rarely do |
| Internal finishes and fit-out | Raised floors, ceiling tiles, doors, ironmongery, sanitaryware | High reuse potential by item count, low by mass |
| Mechanical and electrical plant | Age, capacity, service history, refrigerant type | Reuse limited by remaining life and refrigerant regulation |
| Hazardous and deleterious materials | Asbestos, lead paint, treated timber, contaminated arisings | Removes material from the reuse pool and changes the disposal route |
| Excavation arisings | Volume, soil classification, contamination status | Off-site disposal of soils is often the single largest cost and carbon item |
Two practical notes. Quantities should be in both volume and mass, because reuse targets are usually expressed by mass while the logistics are driven by volume. And the audit needs to be done with access to the building, not from drawings, which means scheduling it before the site is handed over to a demolition contractor who has already priced on assumptions.
The asbestos position comes from a refurbishment and demolition survey under the Control of Asbestos Regulations 2012, carried out by a competent surveyor. That is a separate exercise with its own legal weight, and it should feed the audit rather than be replaced by it.
Setting reuse and recycling targets honestly
The waste hierarchy in the Waste (England and Wales) Regulations 2011 puts prevention first, then preparing for reuse, then recycling, then other recovery, then disposal. Targets that collapse those steps into a single diversion-from-landfill figure hide the thing that matters.
So express targets at each level. Retention in situ as a percentage of existing structure by mass. Reuse on site. Reuse off site. Recycling. Other recovery. Disposal. A scheme that retains 40 per cent of an existing frame has done something far more useful than one that crushes everything and calls it 98 per cent recycled, and the reporting format should make that visible.
Where a policy target exists, apply it to the right denominator. The London Plan sets a high recycling and reuse expectation for construction and demolition waste and a separate one for excavation waste, and the two are not interchangeable. Confirm the current figures and the definitions in the relevant local policy and guidance before quoting a percentage, because the wording moves and the denominator is where disputes start.
Be honest about the ceiling. Crushed concrete used as sub-base on the same site is reliable and will happen. Structural steel reuse in a new frame needs testing, documentation and a designer willing to take the liability, and it does not happen at scale on a tight programme. Setting a steel reuse target you cannot deliver gets you a condition you cannot discharge.
On-site reuse against off-site reuse
The two are different propositions and should be targeted separately.
On-site reuse is the one that pays. Crushed concrete as capping or sub-base, excavated material used in landscape mounding or as backfill, retained slabs used as a working platform, salvaged brick reused in boundary walls on the same scheme. All of it avoids two lorry movements per load and avoids landfill tax. The constraint is space: a site with no room to stockpile and process cannot reuse on site, and that constraint has to be tested against the construction logistics plan before the target is set.
Off-site reuse depends on someone wanting the material at the moment it becomes available. Reclaimed brick, stone, slate, structural timber, raised access flooring and architectural ironmongery have established markets. Most other material does not, and a target that relies on finding a taker is a target with no contractual home.
The mechanism that makes off-site reuse real is a clause in the demolition contract requiring specified materials to be carefully removed, stored and sold or transferred, with the records of where they went. Without that clause, careful removal costs the contractor money and gains them nothing, so it will not happen.
Evidencing the targets after consent
What proves a target was met is paperwork generated during the works, which means the recording system has to be set up before demolition starts.
The documents that do the work are waste transfer notes and consignment notes for hazardous waste, which carry the quantities and the receiving facility. Weighbridge tickets. Records of material crushed and reused on site, which generate no transfer note and therefore need their own log. Sales or transfer records for reclaimed material. And a reconciliation against the audit quantities, explaining the difference between what was expected and what happened.
The waste duty of care under the Environmental Protection Act 1990 and its code of practice already requires much of this, so the incremental effort is in the reconciliation rather than in the record keeping. A site waste management plan is the natural home for the system, even though the regulations that once mandated such plans in England were revoked and the requirement now arrives through planning conditions and client standards instead.
Where this meets the carbon assessment
The audit feeds the embodied carbon work directly. Retention of existing structure avoids the product and construction stage emissions of its replacement, which is usually the largest single carbon saving available on a redevelopment. Reuse of material avoids a smaller but real quantity. And the end-of-life and beyond-boundary modules of a whole life carbon assessment draw on the same destination assumptions the audit established.
Keep the two documents consistent. A carbon assessment claiming the benefit of reusing a frame that the circular economy statement does not commit to retaining will be challenged, and so will a reuse target whose carbon benefit has quietly been counted twice, once as avoided new material and again as a recovery credit.
State the assumptions once, in one place, and reference them from both documents.
When a target becomes a condition
Authorities secure these commitments in three ways, and the drafting is worth attention.
A condition requiring a circular economy statement or waste strategy to be approved before demolition begins. This is the usual route and it is sensible, provided the pre-demolition audit is already done so the submission is not a second round of guesswork.
A condition requiring the development to be carried out in accordance with the approved targets. This is the one to read carefully, because a numerical target written into a condition becomes a planning obligation that is breached if missed, whatever the reason. Ask for wording that requires reasonable endeavours against the target with a reporting mechanism, rather than an absolute percentage.
A section 106 obligation on larger schemes, sometimes with a monitoring fee and a post-completion report. Check what triggers the reporting obligation and who signs it off, because an obligation tied to practical completion can sit awkwardly with a phased build.
Reporting at completion
The post-completion report closes the loop and almost nobody budgets for it.
It should restate the audit quantities, set out what actually happened to each material stream with the supporting records, give the achieved percentage at each level of the hierarchy, and explain the variances. Where a target was missed, say so and say why. An honest report explaining that a steel reuse target failed because no buyer could be found within the programme is a document an officer can accept. A report that quietly reclassifies reuse as recycling to hit a number is the kind of thing that sours a relationship with an authority for years.
Keep the pre-redevelopment audit and the completion report together in the project record. On the next scheme, the reconciliation between the two is the most useful document you own, because it tells you what your targets should have been.
This is general guidance, not legal advice. Pre-demolition audits, asbestos surveys and waste classification should be carried out by suitably qualified people, and councils usually expect a named author for this work.
To see which waste, carbon and demolition documents a scheme is likely to need, enter your postcode on PlanScope and work through the guided questions. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
What is the difference between a pre-demolition audit and an asbestos survey?
The asbestos survey is a refurbishment and demolition survey under the Control of Asbestos Regulations 2012, carried out by a competent surveyor to identify asbestos-containing materials. The pre-demolition audit is a wider quantified inventory of all materials with reuse routes identified. The survey feeds the audit and does not replace it.
Should reuse and recycling be reported as one figure?
No. The waste hierarchy in the Waste (England and Wales) Regulations 2011 separates prevention, preparing for reuse, recycling, other recovery and disposal. Reporting a single diversion-from-landfill percentage hides whether structure was retained. Give a figure at each level, including retention in situ as a percentage of existing structure by mass.
Which reuse targets are actually achievable?
On-site reuse of crushed concrete as sub-base and of excavated material in landscaping is reliable where there is room to stockpile. Reclaimed brick, stone, slate, structural timber and raised flooring have real markets. Structural steel reuse in a new frame needs testing, documentation and a designer willing to accept the liability, so treat it cautiously.
How do you prove a reuse target was met?
With waste transfer and consignment notes, weighbridge tickets, a separate log for material crushed and reused on site that generates no transfer note, sales records for reclaimed material, and a reconciliation against the audit quantities. Set the recording system up before demolition starts, because it cannot be reconstructed afterwards.
Can a reuse target become a planning condition?
Yes, and the wording matters. A condition requiring the development to achieve a stated percentage creates a breach if the target is missed for any reason. Ask instead for reasonable endeavours against the target with a reporting mechanism, and make sure the audit is complete before the submission is drafted.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.