Before demolition: make the materials inventory decision-ready

A decision-ready inventory carries more than a list of materials and quantities. It carries, for each material, the information that determines what can be done with it.

Quantities must be more than indicative. A recovery route is commercially viable or not depending on volume, and a route that works for a large quantity may not work for a small one. The inventory should distinguish what is estimated from what is measured, and should be clear about which materials are present in quantities that justify a separate recovery route.

Condition determines whether a material can be reused as-is, needs processing, or is only suitable for recovery of its constituent material. Structural steel in good condition may be reusable; the same steel corroded or embedded is a different proposition. Condition assessment requires appropriate expertise for the material in question.

Access determines whether the material can be recovered at all in practice. A material present in quantity and in good condition but removable only by destructive means during the demolition sequence is not straightforwardly recoverable. The inventory should record how each material can be reached and removed, and whether that is compatible with the programme.

Segregation requirements follow from the destinations. Different routes accept different materials, and mixing is the most common way a recoverable material becomes waste. The inventory should state what must be kept separate, and the site arrangements that follow.

One dependency sits before all the others and constrains them: the assessment of hazardous materials.

Buildings constructed in different periods contain different materials, and some of those materials — in insulation, cladding, coatings, pipework, sealants and elsewhere — may contain hazardous constituents whose handling is governed by specific regulatory requirements. The assessment of whether a building contains such materials, and how they must be managed, is a specialist exercise conducted under the applicable regime.

This article deliberately does not describe how to identify or handle any such material, and it should not be read as offering any guidance on that. The reason is not caution for its own sake: the requirements are specific, the consequences of getting them wrong are serious, and the assessment requires competence this article cannot supply. What the article can say is that the assessment must be completed before the inventory is treated as decision-ready, because its findings determine which materials can be recovered, how they must be handled, and at what cost.

The same principle applies in a lesser way to other materials. Where there is uncertainty about a material's composition or its regulatory status, the honest position is to record the uncertainty and resolve it through proper assessment rather than to assume the favourable answer.

The most common error in a materials inventory is counting a material as recovered on the basis of an assumed destination.

An assumed end-of-waste status is a particularly clear example. A material may in principle be capable of reaching end-of-waste status, and the fact that it is capable does not mean it has done so, or that a receiving party will accept it on those terms. Until a receiver has confirmed what they will take and on what conditions, the material's destination is unknown and its recovery is unconfirmed.

The practical consequence is that the recovery rate in an inventory can be substantially overstated by counting materials against routes that have not agreed to take them. The correction is procedural: identify the receiving parties, confirm their acceptance criteria, and where the quantity or the material is significant, trial a load before relying on the route.

Transport and processing costs belong in the assessment alongside the receiving party's terms, because a recovery route that costs more to use than disposal is a route that will not be used once the works are under pressure. The inventory should record the economics honestly, including the cost of a rejected load, so that the recovery actually happens rather than being planned and abandoned.

Procurement timing closes the loop. Reception capacity must be arranged before the materials arrive, not after. An inventory that identifies a route but does not secure the capacity to use it has produced a plan that will fail at the point of execution.