By 
August 26, 2025
Are You at Risk? When Damp Repairs Become a Construction Project Under CDM 2015
Damp repairs have a way of creeping up—not just on your walls, but on your legal exposure. If you’ve ever thought, “It’s just patching a flaky bit of plaster,” that naivety can cost you. The truth is, the line between “maintenance” and “construction project” is much thinner than most landlords or property managers realise. Instal a damp-proof course, fit tanking membrane, coordinate two or more trades, or handle any works that touch the structure? You’ve just triggered the Construction (Design and Management) Regulations 2015 (CDM 2015). At that point, the law doesn’t care how minor it feels—your project is now a construction site, and you carry new duties as the legal client.
Once work moves beyond the obvious, every wall and document matters twice as much.
Landlords often assume CDM only applies to obvious building works—extensions, conversions, lofts. But inject a chemical DPC, bring in cavity drain experts, or schedule a plasterer and electrician in one project, and you’re under the CDM umbrella. If works affect the property’s fabric, or involve more than one trade, risk management and compliance tracking become mandatory tasks on your list (HSE, 2023).
The transition from “quick fix” to construction under CDM is almost always invisible until you’re tangled in paperwork. But compliance isn’t optional. Your property’s health and your legal liability are suddenly joined at the hip.
CDM Compliance Triggers in Damp & Mould Work
• Structural impact – Upgrading walls, floors, or fitting membranes changes your building’s bones.
• Specialist damp systems – Chemical injections, tanking, drainage membranes, or clever ventilation work? These jobs ring the CDM bell.
• Multiple trades – If damp pros, plasterers, electricians, joiners or anyone else overlap, your “small job” needs full compliance.
Tick any one, and you’re on the hook for CDM compliance—and so are all your records.
When Is a Landlord the ‘Client’—and What Does That Actually Mean?
If you fund repairs, instruct a contractor, or sign off any work, CDM classes you as the ‘client’. There’s no loophole—CDM 2015 fixes the legal client pin firmly to whoever commissions or bankrolls the repair. That means you’re required to check every risk before the first hole is drilled, declare property hazards, vet every contractor, and keep a paper trail proving you did all this. Just tossing the work to the builder won’t protect you. If you greenlight the project, it’s yours in the eyes of the law.
By simply authorising the repair, you’re on the hook for the site and its paperwork. *(HSE, 2023)*
For nearly every damp or mould project beyond a simple paint touch-up, landlords become the client by default. This piles on concrete expectations: collect pre-construction data, confirm every contractor’s credentials and insurance, and lodge all appointments or compliance paperwork properly (Buildzone 2024).
Core ‘Client’ Requirements
- File every contractor’s qualifications, trade accreditations, and up-to-date insurance.
- Supply pre-construction info about property hazards—any asbestos, electricals, gas.
- Name and sign up duty-holders (Principal Designer, Principal Contractor) before anyone picks up a trowel.
If you approve the job, you’re in charge—for the risks as well as the result.
Why ‘It’s Just Maintenance’ Doesn’t Wash: Health, Safety and Proving Due Diligence
Damp and mould are more than ugly. They lead to health risks, silent structural issues, and, if botched, legal crises you won’t see coming. Once your project hits the CDM threshold, your job is to show risk assessments, share property hazard info, keep contractor credentials up to date, and have proof for each box ticked. Skipping this step isn’t shaving hassle—it’s creating an insurance, mortgage and liability nightmare.
Miss the paperwork and you might miss your next insurance payout or run afoul of council enforcement. *(TrustMark, 2023)*
You can’t sidestep the admin—proper risk assessments, hazard checks, contractor vetting and archiving are legal ammunition if questions ever come your way (IOSH, 2023). It’s not enough to trust a handshake or business card. Archive everything for scrutiny—every skill, every survey, every insurance.
Ask yourself: Do your files prove asbestos checks? Can you verify all contractors on site have both skill and cover? That’s the difference between smooth repairs and months of claims or refusals.
Who Has to Be Officially Appointed? Real Names, Real Accountability
The moment you require more than a single trade—say, a damp injection technician and a plasterer—CDM insists two roles are named: Principal Designer (risk planning and paperwork) and Principal Contractor (site control and safety). Not just a line on a quote: they are people or companies with actual qualifications, written acceptances and traceability in your file.
What Must Be on File for Multi-Trade Damp Repairs?
- Written, pre-job appointment (with acceptance) of Principal Designer and Principal Contractor.
- Credentials, insurance, and job-specific method statements for each specialist.
- Phase-by-phase completion snaps, certificates, and a full chronology—no gaps, no missing proofs.
No Principal Designer or Contractor? No compliance, and little defence if anyone files a claim or complaint. *(RICS, 2022)*
If you skip this documentation, you’re open to fines, insurance refusal, or lender questioning (Designing Buildings Wiki, 2023). Every step needs to be on file—before any van unloads.
Why CDM Isn’t the Only Legal Eagle Watching: HHSRS, Homes Act, and Tenant Claims Run Parallel
CDM compliance is a baseline, not a bulletproof vest. The Housing Health and Safety Rating System (HHSRS), the Homes (Fitness for Human Habitation) Act, and local council enforcement are running in tandem. Delay or skip repairs, fail to document, or let tenant complaints stack up and you risk council bans, fines, even outright letting bans. Your paperwork has to satisfy both building safety and occupancy law.
Lack of documentation at any stage can spark fines or even a letting ban—well beyond the reach of CDM. *(UK Gov 2024)*
Every tenant request, from first contact to signed-off repair, demands a rock-solid record (Government Guidance, 2024). It’s not just about fixing a defect—it’s about proving the fix, with a timeline of reports, images, and closed actions that can stand up to a tribunal or claim.
Lose a report or misfile a photo, and you risk as much pain as you would from bungled repairs—only this time it’s regulatory.
Accreditations, Materials, and Warranties: The New Compliance Currency
Insurance, mortgages, and surveyors work on trust—but only when backed by chain of evidence. “We did the works” isn’t proof. You need:
- Accreditations (TrustMark, Property Care Association, BSI, clear to BS 6576/8102 standards)
- Dated process photographs, instal records, and product receipts
- Every guarantee, insurance and post-repair certificate traceable in a single file
A single missing chain link can disrupt a home sale, cancel a claim outright, or kill a remortgage—no matter how minor the original works seemed.
A missing warranty will delay or even derail both claims and sales. *(PCA, 2023)*
Your compliance archive is an economic asset. No accreditations or missing docs? Expect valuation issues and bigger headaches when surveyors or underwriters review your work (Which?; PCA, 2023).
Meticulous records protect liquidity and give your building a clean bill of health when it counts most.
How Do You Build a Compliance Chain Landlords Can Defend?
Treat compliance as your insurance against future fights. It’s your structural backbone—proof of skill, process, and completion that can outlast audits, disputes, or legal wranglings. Build your archive this way:
- Diagnosis: Full, expert-led survey and documentary root-cause assessment.
- Specification: Treatment plan that directly references BS 6576/8102.
- Appointments and assessments: Written, signed risk logs, and formal appointments for Principal Designer and Principal Contractor.
- Execution records: Dated, phase-by-phase installation photos, materials sheets, and work logs mapping back to your original survey.
- Archival: Guarantees, certificates, remedial logs, and even routine emails—accessible, clear, and indexed.
Having your project’s complete archive on hand is the difference between a seamless remortgage and months of blocked sales. *(HML Group, 2023)*
Surveyors and lenders now expect this “cradle-to-completion” paper chain (HML Group, Landlordzone, 2023). Without it, your compliance claims won’t hold for the next buyer, tenant, or solicitor.
The record doesn’t just defend you—it’s a real market advantage when you sell, remortgage or face any challenge.
Contact Sussex Damp Experts for Damp Repairs That Satisfy Every Regulator
Sussex Damp Experts delivers watertight repairs and bulletproof documentation, ensuring every damp job is genuinely future-proof. From custom diagnosis to phase-by-phase photography, professional insurances and formal post-repair guarantees, every element of our process is shaped by CDM, lender, and insurer requirements. Your compliance file won’t just be a stack of papers—it will be an asset ready to defend your property, accelerate sales, and calm the nerves of the toughest surveyor or underwriter.
Every repair we deliver is a compliance asset—ready to defend, impress, or reassure those who hold property power.
Choose our service and unlock repairs that satisfy every legal and regulatory yardstick. Protect your building, defend your reputation, and secure every door for future deals, lettings, or peace of mind whenever your paperwork’s called up.
Frequently Asked Questions
What specific actions make damp proofing or repair works count as ‘construction work’ under CDM 2015?
Any damp repair that disturbs the structure, instals or renews damp-proof systems, or needs coordination across trades is legally “construction work” under CDM 2015, no matter how small it seems at first glance.
It isn’t about the price tag or job length—it’s the combination of building fabric intrusion, specialist system change (like a chemical DPC or tanking membrane), or simply having to organise more than one trade, even sequentially. Lifting plaster to chase salt, running power tools inside a lived-in home, or managing the interface between heritage and new materials all trigger CDM. If the work plan would flag up as construction to a mortgage lender or surveyor—meaning it goes beyond decoration, hits a wall, or mandates expertise—it qualifies. According to HSE, “construction” is judged by scope and risk, not what a builder or agent calls it (HSE CDM Guidance 2023).
Which repair actions cross this threshold immediately?
- Chasing brickwork or substrate to deliver new DPC lines
- Full-section tanking or cavity membrane installation below ground level
- Any job needing specialist PPE, hazardous material handling, or two or more skilled contractors
- Hybrid or heritage retrofits that change substrate or finishes
A seemingly simple leak fix can become ‘construction’ the moment a wall is cracked open or multiple trades walk onto site together.
If in doubt, getting a surveyor (accredited to BS 6576 or BS 8102) to review and certify your planned works gives you defensible compliance if the council or insurer asks later. Sussex Damp Experts routinely map out works in compliance statements so you’re one step ahead of regulatory scrutiny—guaranteeing no accidental legal overstep.
How does CDM 2015 transform your compliance duties as a landlord, agent, or freeholder tackling damp?
Commissioning significant damp repairs formally turns you into the ‘client’ for CDM—landing you with direct legal duties for planning, evidence, and the appointment of competent trades, even if a managing agent is involved.
As soon as the job leaves “routine decorator” territory, your responsibility escalates: you’re expected to gather up-to-date credentials from everyone involved, communicate hazards to all parties, and document every compliance decision, from risk assessments to completion signoff. There’s no offloading liability onto an agent—letters, schedules, and risk logs must still bear your legal stamp. If trades coordinate (damp proofer, plasterer, electrician) or work intersects (sequence of tasks), you must appoint Principal Designer and Principal Contractor in writing (never just a WhatsApp message). Mortgage reviews, licencing, and building guarantees all demand this compliance evidence—regardless of job size or who manages the property behind the scenes.
What’s the minimum compliance “paper trail”?
- Credentials and up-to-date insurance for each party
- Written appointment letters and signed role acceptance
- Living risk assessments, method statements, and a dated file for each communication
Insurers, local authorities, and even tenants now routinely expect this archive. Sussex Damp Experts include a digital handover file as standard—keeping every landlord or manager on strong legal ground, no matter who asked for the repair.
Why are written health & safety controls essential for any damp or mould job under CDM 2015?
CDM insists that everyone responsible for damp or mould repairs—landlords, freeholders, agents—must secure written health and safety controls for each project, not just say “we’ll be careful.”
A risk assessment isn’t a box-ticker: it must identify all hazards, from air quality (mould spores, dust) to structural surprises (loose plaster, exposed wiring). Contractors need verified TrustMark or PCA status, robust insurance, and proof of live safety training—all filed and stored. The law also asks how tenants are shielded from disturbance, how site safety is briefly explained, and how specialist requirements like ventilation or PPE are handled. Verbal plans or handshakes don’t count; authorities and insurers demand written and dated records if anything goes wrong (TrustMark, CDM 2024).
Where do most compliance gaps open up?
- Forgetting to request updated insurance documentation at the start
- Failing to file signed risk controls and method statements
- Skipping health communication with tenants or site users
If you’re not holding the paperwork, the law acts as if the safety never happened—however diligent your crew.
Sussex Damp Experts make sure every step—risk, method, certification, communication—is signed, filed, and retrievable, insulating you from disputes or repeat surveys during sales or letting.
When exactly must you appoint a Principal Designer and Principal Contractor—and how is this evidenced for damp repairs?
You need a Principal Designer and Principal Contractor, expressly named and confirmed in writing, for any damp repair or retrofit that involves more than one contractor—even if their works don’t overlap.
This splits responsibility between who designs/specifies and who delivers the physical work. Any time a damp proofer works alongside or before/after a plasterer, joiner, or specialist, this formal split must be made. Compliance is measured by paperwork, not intention: you’ll need acceptance letters, role descriptions, and proof of each appointee’s insurance and credentials. Mortgage lenders, council auditors, and even some tenants now request these specifics before authorising funds, licences, or approving insurance claims.
Essential records for dutyholder appointment include:
- Signed letters for both roles (with acceptance)
- Party-specific insurance and accreditations
- Sequenced plans outlining who is responsible, at what stage, for which risk
Dutyholder proof isn’t box-ticking; it’s the evidence line a dispute or site visit will follow, straight to you.
With Sussex Damp Experts, the compliance file always includes full duty appointment and qualification logs, shielding you from council or lender challenge.
How do the HHSRS and Homes Act intersect with CDM, changing landlord damp-proofing compliance?
Even if your property repair dodges CDM, both the HHSRS and the Homes Act put a legal clock on how fast and thoroughly you handle persistent damp or mould—shifting the legal risk profile for all owners and managers.
Category 1 hazards (like recurring black mould, rising damp, or structural wet rot) mean local authorities don’t merely request; they enforce, sometimes forcibly. The Homes Act grants tenants direct power to seek court action if the evidence file is missing—so “prompt” and “thorough” get tightly defined by record-keeping. Properly logged surveys, before/after photos, tenant notifications, and proof of timely repair are now part of your defence file (Gov.uk 2023, Property Ombudsman). Gaps in this file can halt a sale, void insurance, or lead to costly fines—even if the physical repair looks sound.
Which records are now non-negotiable?
- Complete HHSRS and damp risk surveys when hazards are flagged
- Periodic tenant communication and acknowledgement of received reports or notifications
- Tracking and archiving of every repair request and update, even if the problem appears solved
With Sussex Damp Experts, every file stays up to date, ready to prove your compliance instantly—which is proven to speed up future mortgage approvals, sale negotiations, or insurer sign-off.
Which documentation and aftercare routines turn a damp repair into reputational (and legal) security?
A six-year archive of your compliance file turns today’s damp fix into the asset that protects your reputation, insurability, and property value—long after the trades have left the site.
Each archive should include:
- BS 6576/8102 survey logs, specific diagnosis, and before/after condition images
- Appointment and credentialing for every specialist—never just invoices
- Signed risk assessments and method statements for all stages
- Communication logs with stakeholders (tenants, surveyors, insurers)
- Aftercare and maintenance plans with scheduled monitoring, plus all warranty documentation
The repair is in the walls—the safety is in the file. Only the archive survives council, lender, or audit tests.
Sussex Damp Experts deliver a consolidated digital pack, combining everything you might need for future ownership, sale, or claim—structuring evidence so next time a lender, buyer, or local authority asks for confirmation, you’re presenting the benchmark file in the market. No lost paperwork, missed appointments, or forgotten guarantees—just calm, instant proof.
