Damp, Mould and Leaks in Flats: Who Is Responsible?

Damp, mould and leaks are among the most common issues in blocks of flats, and one of the most frequent sources of questions between neighbours. The key to resolving them quickly is to find the cause, because responsibility usually follows the cause. This guide explains how leases typically divide responsibilities, and the practical steps to take.

Start with the lease: demised parts and common parts

Every lease defines the demise: the parts of the building that belong to the flat and that the leaseholder is responsible for. Everything else is usually retained by the landlord or management company as the structure and common parts, repaired by them and paid for through the service charge.

Leases vary, but a typical modern lease of a flat in a purpose-built block includes in the demise:

• Internal plaster, floor finishes and ceilings
• Internal doors, kitchen and bathroom fittings
• Pipes, wires and drains that serve only that flat
• Sometimes the windows and the flat entrance door

And retains for the landlord or management company:

• The roof, foundations, main structure and external walls
• Common parts such as halls, stairs and lifts
• Pipes, wires and drains that serve more than one flat

Converted houses and older leases can draw these lines differently, so the lease for the specific flat is always the starting point.

Finding the cause

Condensation

Condensation forms when warm, moist air meets a cold surface. It often shows as black mould on window reveals, corners of external walls and behind furniture. It is usually linked to ventilation, heating and how moisture is managed within the flat, although cold spots in the structure can contribute.

Penetrating damp

Water entering from outside, through a defective roof, gutter, pointing, render, window seal or balcony, usually points to the building's structure or external envelope, which is normally the responsibility of the landlord or management company.

Rising and ground-level damp

Ground-floor and basement flats can be affected by moisture from the ground, high external ground levels or defective drainage. Diagnosis needs care: these issues are often confused with condensation or plumbing leaks.

Leaks from another flat

A leak through the ceiling often comes from the flat above: a bath seal, a washing machine hose, a shower tray or a pipe serving only that flat. In that case the source is usually within the other flat's demise, and that leaseholder is responsible for stopping it.

What to do when you find a leak

1. If water is coming through, contact the flat above or the source flat straight away, and turn off the water and electrics if it is safe to do so
2. Report it to the managing agent with photos, especially if the source is unclear or in the common parts
3. The managing agent can help trace the source and, where needed, arrange access and a specialist leak detection survey
4. Once the source is fixed, allow time for affected areas to dry out before redecorating
5. Check whether the damage is covered by the buildings insurance (escape of water is a common insured risk) or your contents policy, and note the excess

Mould: practical steps for residents

• Use extractor fans when cooking and bathing, and keep trickle vents open
• Dry laundry outdoors or in a ventilated space where possible
• Keep a steady, moderate level of heating in cold weather
• Leave a gap between furniture and external walls
• Report any mould that keeps returning, as it can signal a building defect

Getting a proper diagnosis

Damp is easy to misdiagnose, and the wrong repair wastes money. A thorough investigation may include:

• A visual inspection inside and out, including roofs, gutters, downpipes, pointing and window seals
• Moisture readings and, where useful, thermal imaging to find cold spots or hidden leaks
• Checking ventilation and extractor fans in kitchens and bathrooms
• Drainage surveys, including CCTV of drains where ground-floor damp is suspected
• Leak detection by a specialist where the source is hidden in floors or walls

Keeping the building weathertight

Many damp problems are avoided altogether by good planned maintenance of the building's envelope. Regular gutter clearance, roof inspections, checks on pointing, render and sealants, and attention to balconies and flat roofs all help keep water out. These items belong in the building's planned maintenance programme, funded through the service charge and the reserve fund.

Damp in the common parts

Damp can also appear in shared areas: basements, bin and cycle stores, stairwells below flat roofs and corridors next to external walls. These areas are usually the responsibility of the landlord or management company, and regular inspections help catch problems early. Typical causes include blocked gutters and gullies, failed roof coverings, defective drainage and poor ventilation in enclosed stores. Residents can help by reporting any staining, musty smells or standing water in the common parts as soon as they notice it.

If you let your flat

Leaseholders who let their flat are landlords to their tenant, with their own legal duties on repairs and on keeping the home fit for human habitation. Respond promptly to your tenant's reports and work with the managing agent where the cause lies in the building.

How a good managing agent helps

Diagnosing damp properly takes construction knowledge. At Westbridge we investigate the cause before any work is commissioned, so leaseholders pay for the right repair once. Where the cause is in the structure or the common parts, we arrange the right independent contractor and inspect the work before it is paid for. Where the cause is in a flat, we help neighbours resolve it quickly and fairly. See our maintenance and repairs service, or contact us.