Building pathology needs building data

On 3 September the Chartered Institute of Housing and the Chartered Institute of Building published joint guidance on damp and mould in social housing. It is the first industry guide written after Awaab's Law Phase 1 and the 2025 Prescribed Requirements regulations, and it adds a new section on the construction causes of damp — aimed at the people who build, retrofit and maintain the stock, not only the people who manage it.

One line from CIOB's David Barnes is worth the whole document. Landlords should keep a strong focus on every individual property's building pathology, rather than rolling out one-size-fits-all measures.

Every individual property. Not the archetype. Not the estate. The home.

The question the guidance leaves open

Building pathology is the right idea. A 1960s flat with a cold bridge at the balcony, a Victorian terrace with a failed damp course and a 2010s block with a ventilation system nobody commissioned are three different problems that happen to produce the same black patch on a wall. Treating them the same wastes money and, worse, sometimes makes the problem worse.

But diagnosing a home individually assumes you know something about that home individually. Most landlords still learn about damp the way they always have: a resident reports it. By then the surveyor is already working backwards from a symptom, and the statutory clock is already running — ten days to investigate, five to make safe.

Twelve weeks

From 30 November, Phase 2 of Awaab's Law widens those duties to excess cold and excess heat, alongside falls, structural, fire, electrical and hygiene hazards. Cold is the one that breaks the reporting model completely. Damp eventually becomes visible. A flat sitting at 15°C all winter looks exactly like one at 21°C. There is nothing to photograph, and an elderly or unwell resident may never report it.

So the guidance's ask — understand each home's pathology — is about to collide with a law whose hazards you cannot see. The only way to reconcile them is to have evidence per property before anyone complains.

What the evidence looks like

Pathology, in practice, is a handful of questions that can be answered with numbers rather than a visit.

• Which rooms sit below 16°C overnight, and for how many nights in a row?
• Where does relative humidity stay above 70% for days at a time — and is that the whole home or one wall?
• Does the humidity track the outdoor weather, the heating schedule or the resident's routine? Each points to a different cause.
• Which homes are drifting towards a threshold this month, rather than already past it?

Continuous temperature and humidity sensors answer all four, per room, every few minutes. That is the raw material of building pathology: not a photograph of one afternoon, but the pattern across a season, in the home you are trying to diagnose.

Data is not the finish line

The honest caveat, and the one the sector keeps tripping over: readings on their own diagnose nothing and close nothing. A screen with fifty amber rooms and no owner has made nobody safer. For monitoring to serve the guidance and the law at the same time, the reading has to be checked against the standard that room is held to, turned into a task with a name and a deadline, chased until it closes, and logged at every step. That log is what a pathology-led approach produces when it works — and what an Ombudsman asks for when it doesn't.

The point

CIH and CIOB have described the right approach. Phase 2 puts a clock on it. Between them they make the case for something the guidance does not spell out: you cannot diagnose a home individually from a complaints inbox. You need its data, continuously, before the resident picks up the phone.

Building pathology needs building data. Twelve weeks is enough time to start collecting it.