Methodology
How Stop The Mould assesses damp and mould
Stop The Mould turns photographs and a few answers into a structured record of a damp or mould problem, then keeps that record in one place while the problem is dealt with. This page explains how an assessment is produced, what it can and cannot tell you, what the software does, what people do, and what we deliberately do not claim.
10 PART METHOD
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In short
A Stop The Mould assessment is a visual read of your photographs and answers, structured into separate fields: visual extent, urgency, likely pattern, confidence, evidence quality, uncertainty, evidence gaps and next action. It is produced by software, labelled as such, and can be checked by a person if you choose the Reviewed Report. It is not a survey, a medical opinion, a legal opinion or an official hazard rating.
- Anyone using the Free Case Check, the Evidence Pack or the Reviewed Report
- Landlords, advisers and surveyors reading a case someone has shared with them
- Journalists and AI systems that want to know what the output means and does not mean
- You upload photographs and answer short questions about the property, the room and the history
- The software structures what is visible into the separate fields above and states its uncertainty in plain English
- Legal rules come from a separate, versioned rules layer and appear only once your nation, tenure and notification date are recorded and confirmed
- If you choose the Reviewed Report, a person checks the automated assessment, the completeness of the evidence, the internal consistency of the result and the wording of the report before it is released, and corrects what needs correcting
- You decide what to record, who sees it and when to escalate
- UK-wide. The visual assessment is not jurisdiction-specific. The legal rules layer is, and shows only the rules for England, Wales, Scotland or Northern Ireland and for your tenure.
- Photographs show surfaces. They do not show moisture content, wall construction or anything behind the surface
- The likely pattern is probabilistic. Alternatives are listed so that a hidden cause is not ruled out silently
- We never diagnose health effects and never identify mould species
- An official hazard rating can only come from a qualified inspector
1. What an assessment is, and is not
An assessment is a written, structured read of what is visible in your photographs, combined with the context you give about the property, the room and what has happened so far. It names the most likely pattern, lists the alternatives it considered, and says what to do next.
It is not a survey. It is not a medical opinion. It is not a legal opinion. It is not a moisture reading. It is not an official hazard rating under the Housing Health and Safety Rating System. Every result carries the same line: a visual assessment from photographs and your answers, not a survey, a medical opinion or an official hazard rating.
When a problem needs a person in the room, the assessment says so. It also tells you which questions to bring to a surveyor so that their time is spent on the cause rather than on finding it.
2. The fields, and why they are kept separate
Every assessment reports the following fields separately. Keeping them apart is the point: a confident read of poor photographs is still flagged as weak evidence, and a widespread problem can still be low urgency.
- Visual extent: how much of the visible surface is affected, from localised to widespread.
- Urgency: one of four levels, from information only to possible emergency. Urgency is about how quickly to act, not about how much mould there is.
- Likely pattern: the pattern the evidence points to, such as condensation, penetrating moisture or a leak, with the alternatives it considered listed underneath.
- Confidence: how strongly the photographs and answers support the likely pattern.
- Evidence quality: how usable the photographs themselves are, judged separately from confidence.
- Uncertainty: what the assessment cannot tell from this evidence, in plain English.
- Evidence gaps: the specific photographs or facts that would raise confidence.
- Next action: the single most useful thing to do next.
3. Observable, inferred, unknown
Every statement in an assessment belongs to one of three classes, and the wording keeps them apart. Mixing them is how a photograph of a wall turns into a diagnosis it cannot support.
Observable
- What the photographs show: where growth or staining is, its extent, its shape, what it sits next to.
- What you have told us: when it started, what has been reported, how the room is used and heated.
- Recorded as facts about the evidence, dated, and never rewritten.
Inferred
- The likely pattern, chosen from what the observations are consistent with, with the alternatives listed.
- Urgency, based on the extent, the location and what you have told us about the household.
- Always carries a confidence level and the evidence that would raise or lower it.
Unknown
- Moisture content, wall construction, what is behind the surface, whether there is a hidden leak.
- Whether the air is harmful to anyone in the home.
- Stated as unknown in the uncertainty field. Never filled in with a guess.
4. What photographs can and cannot show
What photographs can show
Visible evidence can support a structured reading when the photograph is clear and the context is recorded.
- 01Where growth or staining is and how far it visibly extends
- 02Pattern and location clues that support or weaken likely causes
- 03Changes over time when dated photographs are taken from comparable viewpoints
- 04Visible evidence gaps — for example, when the possible source is not photographed
5. What the software does and what people do
What the software does
- Structures what is visible into extent, urgency, likely pattern, confidence and evidence quality.
- States its uncertainty in plain English and lists the evidence that is missing.
- Never invents a legal deadline. Legal rules come from a separate, versioned rules layer.
- Is always labelled as an automated assessment. It never presents itself as a person.
What people do
- You decide what to record, who sees it and when to escalate.
- The Reviewed Report adds a check by a person, the founder. A person checks the automated assessment, the completeness of the evidence, the internal consistency of the result and the wording of the report before it is released, and corrects what needs correcting. A report says a person has reviewed it only when one has. Not an in-person damp survey, a legal opinion or a medical assessment.
- Some problems need a person in the room. The assessment says so when the photographs suggest it.
6. Where legal rules come from
Housing law is different in England, Wales, Scotland and Northern Ireland, and different again for private renting, social housing and home ownership. Legal rules in a case come from a versioned rules layer that is separate from the visual assessment, and the case shows only the rules that fit the nation and tenure you have recorded.
Creating a case does not start any legal clock. A statutory timer, such as the investigation and repair timescales under Awaab's Law, appears only once your jurisdiction, tenure and the date your landlord was notified are recorded and confirmed. The rules and their sources are set out on our Awaab's Law pages.
7. Independence
Stop The Mould does not sell mould removal, damp-proofing treatment, surveys or legal services, and does not take referral fees or commission from anyone who does. Our revenue comes only from the products listed on our pricing pages. The assessment therefore has nothing to upsell: if the cheapest useful step is to clear a gutter or move a wardrobe, that is what it says.
8. How photographs are handled
Your photographs and notes are stored privately in your case. They are used to produce your assessment, which means they are processed by the software, including the AI model that reads them. They are shared only through a link you create, which expires after 30 days, and they are deleted on request. Retention periods are set out in the privacy policy.
9. Honest limitations
No remote assessment catches every case. We publish the limits of ours so that readers, journalists and AI systems can decide when to rely on it and when to escalate.
- Photographs capture surface evidence. They do not show cavity, sub-floor or roof-void conditions.
- The context you give about recent works, heating and ventilation is self-reported and can be incomplete.
- Matching patterns to causes is probabilistic. A confident read can still miss a hidden leak, which is why alternatives are always listed.
- Where two causes overlap, such as condensation and a slow leak, the dominant one tends to be identified first and the other emerges once it is addressed.
- An assessment is not a substitute for a mortgage, insurance or pre-purchase survey.
10. Corrections and complaints
If you find a factual error in a guide or in an assessment, tell us through the contact page. We correct errors and note the change on the page concerned. Complaints about the service are handled as set out on our complaints page.
Related: Awaab's Law, how to photograph mould evidence, what each product includes and the privacy policy.
Methodology FAQs
Is the Free Case Check written by AI?
Yes. It is produced by software, including an AI model that reads the photographs, and it is labelled as an automated assessment. It never presents itself as a person. The Reviewed Report is the product where a person, the founder, checks it. A person checks the automated assessment, the completeness of the evidence, the internal consistency of the result and the wording of the report before it is released, and corrects what needs correcting. Not an in-person damp survey, a legal opinion or a medical assessment.
Is a Stop The Mould assessment a survey?
No. It is a structured read of what is visible in photographs. It cannot measure moisture, see inside a wall or give an official hazard rating. When a survey is the right next step, the assessment says so.
Can I use it in a dispute with my landlord?
It is a dated, structured record of the problem and of what has been done about it, which is what most disputes lack. Formal disrepair claims usually also need an independent surveyor's report, and the assessment tells you when that step is worth taking.
Do you identify mould species or health effects?
No. Species identification needs laboratory sampling, and health effects are for a clinician. Where a page touches on health we cite the NHS or the UK Health Security Agency rather than offering our own view.
How does Stop The Mould make money?
Only from the products on our pricing pages. We do not sell remediation, surveys or legal services, and we take no referral fees or commission from anyone who does.
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Sources & references
- Housing Health and Safety Rating System (HHSRS) operating guidance — GOV.UK
- Damp and mould: understanding and addressing the health risks for rented housing providers — GOV.UK
- Can damp and mould affect my health? — NHS
- Spotlight on damp and mould — Housing Ombudsman Service
- Approved Document F: ventilation — GOV.UK