Preventing damp and mould in 2026 under Awaab's Law

Damp and mould remain two of the most persistent challenges facing UK landlords, affecting approximately 9% of properties in the private rented sector according to the English Housing Survey. The tragic death of two-year-old Awaab Ishak in 2020 from prolonged exposure to mould brought the issue into sharp focus, leading to the introduction of Awaab's Law. Now extending to the private rented sector through the Renters' Rights Act from 1 May 2026, landlords face strict timescales for addressing damp and mould hazards, alongside potential penalties for non-compliance.

Understanding how to prevent, identify, and treat damp is no longer optional for landlords. It's a fundamental responsibility that protects tenant health, preserves property value, and keeps you on the right side of increasingly stringent regulations. This August article explains what causes damp and mould, how a damp proof course works, your legal obligations under Awaab's Law, and practical steps to stop damp and mould before they become serious problems.

What causes damp and mould in rental properties?

Damp occurs when moisture builds up in a property, affecting walls, floors, ceilings, and possessions. Left unchecked, damp creates perfect conditions for mould growth, those black, green, or white patches that appear on surfaces and release spores that can trigger respiratory problems, allergies, and other health issues.

There are three main types of damp that affect rental properties, each with distinct causes and solutions.

Rising damp

Rising damp occurs when groundwater moves upwards through walls and floors via capillary action, similar to how a sponge absorbs water. This typically happens in properties without adequate damp proofing or where the existing damp proof course has failed or been bridged.

Signs of rising damp include tide marks on walls up to one metre from the floor, damaged skirting boards and plaster, peeling wallpaper or paint near floor level, and a distinctive musty smell. White salt deposits, called efflorescence, often appear on affected surfaces as moisture evaporates.

Rising damp is always the landlord's responsibility to fix. It requires professional intervention, often involving installing or repairing a damp proof course, replastering with specialist materials, and potentially addressing external drainage issues.

Penetrating damp

Penetrating damp, also called lateral damp, occurs when water enters a property from outside through defects in the building's structure. Common causes include damaged roof tiles, blocked or broken guttering and downpipes, cracked rendering or brickwork, faulty window seals, and poorly maintained chimney stacks.

Unlike rising damp, penetrating damp can appear anywhere on walls, ceilings, or around windows, often creating damp patches that worsen during wet weather. You might notice water stains, peeling paint, or mould growth near the affected area.

Penetrating damp is the landlord's responsibility as it stems from property disrepair. Regular property maintenance helps identify issues before they become serious problems. August's maintenance reporting lets you log repairs, set reminders for inspections, and keep records of work carried out, ensuring nothing falls through the cracks.

Condensation

Condensation forms when warm, moisture-laden air meets cold surfaces like windows, walls, or ceilings, causing water droplets to form. It's particularly common in winter when heating creates temperature differences between inside and outside.

Everyday activities generate significant moisture. A family of four produces approximately 10-15 litres of water vapour daily through cooking, bathing, breathing, and washing clothes. Without adequate ventilation, this moisture has nowhere to go and condenses on cold surfaces, creating ideal conditions for mould.

Condensation is trickier when it comes to responsibility. Tenants have a duty to ventilate properties reasonably, open windows regularly, use extractor fans, and avoid practices like drying clothes on radiators without adequate ventilation. However, landlords must ensure properties have adequate heating, proper ventilation systems, and reasonable insulation. If a property lacks these basics, condensation issues fall on the landlord even if tenant behaviour contributes.

What is a damp proof course?

A damp proof course, often abbreviated as DPC, is a barrier built into walls to prevent rising damp. It sits horizontally in the wall, typically around 150mm above ground level, and stops moisture from the ground rising up through the brickwork via capillary action.

How damp proof courses work

Traditional damp proof courses use impermeable materials that water cannot pass through. In properties built before the 1875 Public Health Act, which made damp proofing mandatory, there often isn't a DPC at all. These older properties relied on thick walls and natural ventilation to manage moisture, which doesn't meet modern standards.

Properties built between 1875 and the 1960s typically have slate or bitumen felt DPCs. From the 1960s onwards, most properties use plastic DPC membranes, which are more durable and flexible than older materials.

A damp proof course works alongside other damp proofing measures. Damp proof membranes protect floors, usually consisting of a plastic sheet laid under concrete floors during construction. Good drainage around the property's perimeter prevents water accumulating near walls. Air bricks provide ventilation to spaces under suspended floors, keeping them dry and preventing timber decay.

When damp proof courses fail

Even well-installed damp proof courses can fail or become ineffective over time. Common problems include the DPC being bridged by raised ground levels, where soil, paving, or debris has built up against the wall above the DPC level, allowing moisture to bypass it entirely.

Rendering or cement applied over the DPC can create a bridge, as can internal plastering that extends below the DPC. Cavities filled with rubble or mortar droppings during construction or renovation work can also allow moisture to cross the cavity and bypass the DPC.

Physical damage from building work, settlement, or age can crack or break the DPC. In older properties, slate DPCs can slip or deteriorate, whilst bitumen felt can perish over decades of exposure.

Installing a new damp proof course

If your property lacks a DPC or the existing one has failed, professional installation is essential. The most common method for retrofit installations is chemical injection, where a series of holes are drilled into the mortar bed and a silicone-based water-repellent fluid is injected under pressure. This creates a new chemical barrier that stops moisture rising.

Physical DPC installation involves cutting a horizontal slot through the wall and inserting a new plastic or slate DPC. This method is more disruptive and expensive but provides a permanent solution for properties where chemical injection isn't suitable.

Electro-osmotic systems use electrical charges to repel moisture back into the ground. These systems work well for particularly severe cases or where other methods aren't feasible, though they require ongoing power and maintenance.

Professional DPC installation typically costs between £1,500 and £5,000 depending on property size, wall thickness, the extent of the problem, and the chosen method. Whilst not cheap, a proper DPC installation protects your property value and prevents far more expensive damage from ongoing damp problems.

Awaab's Law: what landlords must know in 2026

Awaab's Law, named after two-year-old Awaab Ishak who died from prolonged mould exposure in social housing, introduces strict timescales for landlords to investigate and fix serious health hazards including damp and mould. Originally applying to social housing from 2023, the law extends to the private rented sector through the Renters' Rights Act from 1 May 2026.

The requirements under Awaab's Law

When a tenant reports a hazard that could seriously harm health, including significant damp and mould, landlords must respond within strict timescales. For urgent and emergency hazards, landlords must start investigating within 24 hours. For serious but non-emergency hazards, investigation must begin within seven days.

Once investigation identifies the cause, repairs must commence within a reasonable timeframe. For emergency issues, work should start immediately or within 24 hours. Serious hazards require repairs to begin within 14 days. The law recognises that complex problems may take time to fix completely, but work must progress without unreasonable delay.

Landlords must keep tenants informed throughout. When a hazard is reported, acknowledge the report quickly, explain what investigation and repairs will involve, provide realistic timescales for completion, and update tenants if circumstances change.

What constitutes a serious hazard?

Not all damp and mould triggers Awaab's Law timescales. The Housing Health and Safety Rating System (HHSRS) assesses hazards based on their likelihood and severity. Category 1 hazards pose serious and immediate risk to health and must be dealt with urgently. Category 2 hazards are less serious but still require attention.

Extensive mould growth affecting multiple rooms or large areas, particularly in bedrooms, constitutes a serious hazard. Widespread damp causing structural damage or significantly affecting living conditions also qualifies. Mould near beds or in areas where children or vulnerable people spend significant time is treated particularly seriously.

A small patch of mould on a bathroom windowsill caused by inadequate ventilation after showers might not constitute a serious hazard, especially if easily remedied. However, mould spreading across bedroom walls, appearing on clothing or furniture, or causing persistent health symptoms absolutely does.

Penalties for non-compliance

Local authorities can take enforcement action against landlords who fail to meet Awaab's Law requirements. This includes issuing improvement notices requiring specific work within set timescales, prohibition orders preventing property occupation until issues are resolved, and financial penalties reaching £30,000 for serious breaches.

Beyond official penalties, failing to address damp and mould exposes landlords to rent repayment orders where tenants can reclaim up to 12 months' rent. Tenants may withhold rent or pursue compensation for damaged possessions or health impacts. In extreme cases, landlords face prosecution for providing properties unfit for human habitation.

The reputational damage shouldn't be underestimated either. Damp and mould complaints frequently appear in tribunal decisions and media coverage, making it harder to attract quality tenants and potentially affecting property values.

How to get rid of damp and mould

Discovering damp and mould in your rental property requires immediate action. The approach depends on the type and severity of the problem.

Emergency response

If a tenant reports extensive mould or damp affecting their health, treat it as an emergency. Acknowledge the report within 24 hours, arrange an inspection within seven days maximum, and provide temporary solutions if immediate repairs aren't possible. This might include supplying a dehumidifier, arranging temporary heating, or in severe cases, offering alternative accommodation.

Document everything. Take photographs of affected areas, record dates of reports and responses, keep copies of all correspondence, and note what actions you've taken. August's document management provides secure, accessible storage for inspection reports, photographs, contractor quotes, and correspondence, keeping everything organised by property.

Treating mould growth

For surface mould on non-porous surfaces like tiles, glass, or painted walls, cleaning with a fungicidal wash removes visible mould and kills remaining spores. Follow product instructions carefully, ensure good ventilation whilst cleaning, and always wear gloves and a mask as mould spores can cause allergic reactions.

However, cleaning surface mould is only treating the symptom. Without addressing the underlying damp problem, mould returns within weeks or months. This is why it's crucial to identify and fix the root cause.

For porous materials like wallpaper, ceiling tiles, or soft furnishings with extensive mould contamination, replacement is often necessary as mould penetrates deep into the material where cleaning can't reach.

Fixing the underlying cause

Rising damp requires professional DPC installation or repair, along with replastering affected walls with moisture-resistant materials. The damp must be allowed to dry thoroughly before replastering, which can take several weeks depending on wall thickness and moisture levels.

Penetrating damp solutions vary by cause. Roof repairs address tile damage or flashing problems. Gutter and downpipe maintenance ensures water drains away from the building. Repointing or rendering repairs seal cracks in external walls. Window and door seal replacement prevents water ingress around openings.

Condensation requires a combination of improved ventilation, adequate heating, and tenant education. Install or repair extractor fans in bathrooms and kitchens, ensure trickle vents in windows are working and not blocked, provide adequate heating throughout the property, and consider dehumidifiers for particularly problematic rooms.

Working with specialists

For anything beyond minor condensation issues, professional advice is worthwhile. Damp and timber specialists can conduct moisture surveys using specialised equipment, identify the type and source of damp, recommend appropriate treatments, and provide guarantees for work carried out.

Whilst specialist reports cost between £200 and £500, they provide clarity when the cause isn't obvious, evidence for insurance claims or disputes with tenants, and confidence that the chosen treatment will work. For landlords managing multiple properties, building relationships with reliable specialists saves time and ensures consistent standards.

How to stop damp and mould in bedrooms

Bedrooms are particularly susceptible to condensation and mould because they're often poorly ventilated, kept cooler than other rooms to aid sleep, and contain sources of moisture from breathing and body heat during sleep.

Preventing bedroom condensation

Each person releases approximately 40g of moisture per hour whilst sleeping. In a double bedroom, that's nearly 400g of water vapour during an eight-hour sleep. Without adequate ventilation, this moisture condenses on cold walls, windows, and furniture.

Encourage tenants to open windows for 10-15 minutes each morning to release overnight moisture, even during winter. Keep bedroom doors open during the day to allow air circulation throughout the property. Ensure wardrobes and furniture aren't pushed tight against external walls, leaving a gap allows air circulation and prevents cold spots where condensation forms.

Trickle vents in bedroom windows should remain open. These small vents provide background ventilation without creating draughts. If windows lack trickle vents, consider retrofitting them, particularly in properties prone to condensation.

Heating considerations

Maintaining consistent, moderate heating prevents the cold surfaces that cause condensation. Properties should be heated to at least 18°C in bedrooms, with living areas warmer. Intermittent heating, where properties warm up then cool down completely, creates perfect conditions for condensation as warm air hitting cold walls produces moisture.

Adequate insulation keeps wall temperatures higher, reducing condensation risk. Cavity wall insulation, loft insulation, and double glazing all help. For properties that can't have cavity wall insulation, internal insulation or insulated plasterboard can improve warmth and reduce cold spots.

Tenant education

Many condensation problems stem from misunderstanding about ventilation. Tenants often worry that opening windows wastes heating and increases bills. Explaining that brief periods of ventilation are more effective and economical than dealing with mould damage helps secure cooperation.

Provide clear, written guidance on preventing condensation as part of your tenancy agreement. Cover opening windows daily, using extractor fans, reporting leaks or damp immediately, not blocking vents, and avoiding drying large amounts of washing indoors without ventilation.

Include this information in your welcome pack for new tenants, reinforced during periodic inspections. When tenants understand why these practices matter, compliance improves significantly.

Wet weather and property maintenance

The UK's wet climate means landlords must stay vigilant about property maintenance, particularly systems that manage rainwater.

Guttering and downpipes

Blocked or damaged guttering is one of the most common causes of penetrating damp. Leaves, moss, and debris accumulate in gutters, causing overflow during heavy rain. Water running down walls saturates brickwork, leading to damp patches internally.

Gutters should be cleaned at least twice yearly, typically in autumn after leaf fall and in spring. More frequent cleaning is needed for properties surrounded by trees. During inspections, check for sagging gutters suggesting broken brackets, cracks or holes in guttering, downpipes pulling away from walls, and ground saturation near downpipe outlets.

Downpipes should discharge into proper drainage, either connected to the drainage system or, for older properties, into gullies or soakaways positioned away from the building. Never allow downpipes to discharge directly against walls or into areas where water can't drain away.

Roof maintenance

Even small roof defects can cause significant internal damp. During property inspections, look for missing, cracked, or slipped roof tiles, damaged flashing around chimneys or roof junctions, moss or vegetation growth indicating age or damage, and signs of sagging suggesting structural problems.

Roof repairs shouldn't be delayed. What starts as a small leak during heavy rain can quickly worsen, causing ceiling damage, insulation degradation, and electrical hazards. Winter storms are particularly harsh, so schedule roof inspections in late summer or early autumn to identify problems before wet weather arrives.

External walls and pointing

Brickwork and mortar deteriorate over time, allowing water penetration. Crumbling mortar between bricks, cracks in rendering, and porous brickwork all allow moisture ingress during wet weather.

Repointing involves removing damaged mortar and replacing it with fresh mortar, preventing water entering the wall structure. Rendering repairs seal larger cracks or damaged areas. For properties with significant external wall issues, specialist damp proofing paints or water-repellent treatments can provide additional protection.

Ground levels and drainage

Pay attention to ground levels around your property. Soil, paving, or gravel shouldn't be higher than the damp proof course. If ground levels have risen, often due to landscaping work or gradual soil accumulation, water can bypass the DPC entirely.

Ensure proper drainage away from the building. The ground should slope gently away from walls, preventing water pooling against foundations. For properties in areas prone to flooding or with high water tables, additional drainage measures like French drains might be necessary.

Regular inspections and proactive maintenance

Prevention beats cure every time when it comes to damp and mould. Regular inspections identify problems before they become serious, protecting tenant health and property value.

Creating an inspection schedule

Landlords should conduct formal property inspections at least twice yearly, ideally in spring and autumn. Spring inspections identify winter weather damage and prepare properties for summer. Autumn inspections ensure properties are ready for winter's challenges.

Use a systematic approach, checking the same areas every time. Create a checklist covering external inspection of roof, guttering, walls, and drainage, internal inspection for signs of damp, mould, or condensation, operation of heating and ventilation systems, and tenant lifestyle factors that might contribute to problems.

August's compliance checklist helps landlords track inspections across multiple properties with smart reminders ensuring you never miss important maintenance dates. Document findings with photographs, note required actions, and track completion, maintaining a comprehensive maintenance history for each property.

Responding to tenant reports

When tenants report damp or mould, respond quickly. Even if you suspect the cause is condensation rather than structural damp, acknowledge the report within 24 hours and arrange an inspection.

Ask tenants to describe the problem in detail, provide photographs if possible, and explain when they first noticed the issue and whether it's worsening. This information helps you assess urgency and prepare for the inspection.

During inspection, look beyond the obvious. A damp patch on a wall might result from a leaking gutter outside, condensation from poor ventilation, or a plumbing leak. Thorough investigation prevents treating symptoms whilst missing the actual cause.

Building good relationships

Tenants who trust their landlord to respond quickly and effectively are more likely to report problems early when they're easier and cheaper to fix. Those who've experienced delayed responses often wait until problems become severe before reporting again.

Clear communication helps. Explain what you're doing to investigate and fix problems, provide realistic timescales, and keep tenants updated on progress. If repairs take longer than expected, explain why rather than leaving tenants in the dark.

August's maintenance reporting keeps communication organised. Log every report, record your response, track contractor appointments, and store completion certificates. This creates a clear paper trail protecting both parties and demonstrating your professional approach.

Insurance considerations

Standard landlord insurance policies typically cover sudden and unexpected damage but exclude gradual deterioration, lack of maintenance, or pre-existing conditions. Understanding what your insurance covers helps you make informed decisions when damp problems arise.

What landlord insurance typically covers

Most policies cover escape of water damage from burst pipes or appliances, storm damage to roofs or external walls, and accidental damage to the building structure. If penetrating damp results from storm damage that broke roof tiles overnight, your insurance likely covers repairs.

However, insurance won't cover damp from neglected maintenance like blocked gutters you should have cleared, gradually worsening roof issues you were aware of but didn't fix, or condensation problems from inadequate ventilation that's existed for months.

Making successful claims

If damp results from an insurable event, report it to your insurer immediately. Provide evidence including photographs of the damage, dates when the problem occurred, details of what caused the damage, and estimates of repair costs.

Take reasonable steps to prevent further damage. If a storm damages your roof causing water ingress, arrange temporary repairs to prevent additional rainwater entering. Insurers expect landlords to act reasonably to mitigate losses.

When insurance won't help

For non-insurable damp problems, costs fall entirely on you as the landlord. This is why preventive maintenance makes economic sense. An annual gutter clean costing £100 prevents penetrating damp repairs potentially costing thousands.

Consider the long-term financial impact of damp. Beyond immediate repair costs, there's void periods whilst work is completed, potential rent reductions if tenants withhold rent due to disrepair, and depreciation in property value if damp causes lasting damage.

Compliance beyond Awaab's Law

Whilst Awaab's Law specifically addresses response times for reported hazards, landlords' responsibilities around damp and mould extend much further.

Fitness for human habitation

The Homes (Fitness for Human Habitation) Act 2018 requires rental properties to be fit for human habitation at the start of the tenancy and throughout. Properties with serious damp and mould problems fail this standard.

Tenants can take landlords to court if their home is unfit for habitation. Courts can order repairs to be carried out, award compensation for inconvenience and damage to possessions, and in severe cases, order rent repayment.

Housing Health and Safety Rating System

Local authorities use the HHSRS to assess residential properties for health and safety hazards. Damp and mould create hazards in several categories including excess cold if damp makes heating inefficient, mould growth releasing spores, and entry of water causing structural damage.

If an Environmental Health Officer identifies Category 1 hazards, they must take enforcement action. This can include improvement notices requiring specific works, prohibition orders preventing property use until issues are resolved, and emergency remedial action carried out at your expense.

Deposit disputes

Damp and mould frequently feature in deposit disputes. Tenants argue they shouldn't pay for redecoration when mould damaged walls. Landlords counter that inadequate ventilation caused the problem.

Adjudicators consider whether the landlord maintained the property properly, including ensuring adequate heating and ventilation, whether the tenant followed reasonable practices to prevent condensation, and whether either party reported problems and how the other responded.

Good documentation throughout the tenancy is crucial. Initial check-in reports showing no damp or mould, periodic inspection records, correspondence about any reported issues, and check-out reports comparing property condition all provide essential evidence.

Looking ahead: preparing for stricter standards

The Renters' Rights Act represents a significant shift in tenant protections, with Awaab's Law being just one element. The Decent Homes Standard will be extended to the private rented sector, potentially in 2027-2028, setting minimum standards for heating, insulation, and ventilation.

Properties will need adequate thermal insulation, efficient heating systems, good condition windows and doors, and proper ventilation to prevent condensation. Properties failing these standards will require upgrading to remain legally lettable.

Investing in prevention

Forward-thinking landlords are already upgrading properties to meet anticipated standards. This includes installing mechanical ventilation with heat recovery (MVHR) systems in properties prone to condensation, upgrading insulation beyond current minimum EPC requirements, replacing inefficient heating systems with modern alternatives, and addressing any structural issues that could cause damp.

These improvements require upfront investment but offer multiple benefits. They reduce ongoing maintenance costs, attract quality tenants who value well-maintained homes, command higher rents justifying the investment, and protect property values as standards tighten.

Using technology

Modern property management tools help landlords stay on top of maintenance and compliance. August combines rent tracking, expenses tracking, document management, smart reminders, maintenance reporting, compliance checklist, and property insights in one landlord app.

When a tenant reports damp, log it in August's maintenance reporting. Track your investigation, and see the progress. Smart reminders ensure follow-up inspections don't slip through the cracks, whilst AI Property Assistant can answer questions about your properties and tenancies, and suggest appropriate actions.

For landlords managing multiple properties, this systematic approach ensures consistent standards across your portfolio, protects you if disputes arise, and demonstrates professional property management.

Moving forward with confidence

Damp and mould are manageable challenges when approached systematically. Understanding the different types of damp, their causes, and effective treatments empowers you to act quickly and appropriately. Installing or maintaining proper damp proof courses protects properties from rising damp, whilst good maintenance prevents penetrating damp and condensation problems.

Awaab's Law from May 2026 makes rapid response to serious hazards mandatory, but professional landlords should already be acting quickly when tenants report damp or mould. Protecting tenant health, preserving property value, and maintaining your reputation all depend on treating these issues seriously.

Regular inspections, proactive maintenance, clear tenant communication, and proper documentation create a robust approach to managing damp and mould. Combined with modern tools like August, which help you stay organised across multiple properties and compliance requirements, you can manage your portfolio confidently and professionally.

The regulatory landscape for landlords continues to evolve, with standards rising and tenant protections strengthening. Landlords who embrace these changes, invest in their properties, and maintain high standards will continue to succeed in the private rented sector. Those who view compliance as a burden rather than an opportunity risk penalties, disputes, and ultimately, an unsustainable business model.

Take action today. Review your properties for damp risks, schedule maintenance, ensure your insurance is adequate, and consider how tools like August can help you manage compliance across your portfolio. Prevention is always better than cure, and nowhere is this truer than with damp and mould.

Disclaimer: This article is a guide and not intended to be relied upon as legal or professional advice, or as a substitute for it. August does not accept any liability for any errors, omissions or misstatements contained in this article. Always speak to a suitably qualified professional if you require specific advice or information.