Why Spring Is the Time to Check for Winter Damage
Winter takes a toll on London properties. Frost, driving rain, high winds, and cold temperatures all stress your home's fabric, from the roof tiles down to the foundations. Problems that started small in November can become serious by March.
Spring is the ideal time to assess the damage. The weather is milder, days are longer, and you have the opportunity to spot issues before they worsen. A thorough post-winter inspection can save you thousands in repairs by catching problems early.
This guide walks you through what to look for, where to check, and when to call in a professional.
What Winter Does to London Homes
London's housing stock is particularly vulnerable to winter weather. Victorian and Edwardian terraces, converted flats, and older properties with solid walls all face specific challenges during the colder months.
Frost Damage
Freezing temperatures cause water in porous materials to expand. This can crack roof tiles, damage pointing, and cause brickwork to spall. Repeated freeze-thaw cycles throughout winter gradually weaken the building envelope, creating entry points for water.
Wind Damage
Strong winds can dislodge roof tiles, lift flashing, and damage gutters and downpipes. Even small gaps allow water to penetrate, leading to internal damp and potential timber decay.
Blocked Gutters and Drains
Fallen leaves, moss, and debris accumulate in gutters over autumn and winter. When gutters overflow, water runs down external walls, saturating the brickwork and causing penetrating damp. Blocked drains can lead to standing water around foundations.
Condensation Buildup
During winter, reduced ventilation and increased indoor moisture create perfect conditions for condensation. This often leads to black mould growth in corners, around windows, and behind furniture. What starts as surface condensation can develop into more serious damp issues if left unchecked.
Ground Movement
London's clay soils expand and contract with moisture levels. Winter rain followed by spring drying can cause ground movement, leading to cracks in walls and potential structural issues.
The External Inspection: What to Check Outside
Start your post-winter inspection from the outside. Many damp problems originate from external defects that allow water into the building.
Roof
Look at your roof from ground level (use binoculars if needed). Check for:
Missing, cracked, or slipped tiles
Damaged or lifted flashing around chimneys and vents
Sagging or uneven roof lines
Moss buildup that could be holding moisture
Ridge tiles that look loose or have cracked mortar
If you spot obvious damage, don't climb on the roof yourself. Arrange a professional inspection.
Gutters and Downpipes
Blocked gutters are one of the most common causes of penetrating damp. Check for:
Leaves, moss, and debris blocking the flow
Sagging sections where brackets have failed
Cracks or splits, especially at joints
Overflowing during rain (water marks on walls below gutters)
Downpipes that have become disconnected or blocked
Clear any debris you can safely reach. Consider installing gutter guards to prevent future blockages.
External Walls
Walk around the property and examine the walls for:
Cracks in brickwork or render
Damaged or missing pointing (the mortar between bricks)
Green algae or moss growth indicating persistent damp
White salt deposits (efflorescence) suggesting moisture movement
Peeling paint or blown render
Pay particular attention to areas below windows, around doors, and at the base of walls where water splashes up from the ground.
Pointing and Brickwork
Pointing deteriorates over time and winter accelerates the process. Check the depth of mortar joints. If you can push your finger into the mortar and it crumbles, repointing is needed. Failed pointing allows rainwater to penetrate the wall.
Ground Levels and Drainage
Look at ground levels around your property:
Is soil or paving built up against the walls above the damp proof course?
Are there areas where water pools after rain?
Are drains and gullies clear and flowing freely?
Is there adequate fall away from the building?
High ground levels and poor drainage are common causes of damp in London properties, particularly in basement and lower ground floor flats.
Windows and Doors
Check the seals around windows and doors:
Are there gaps where sealant has shrunk or failed?
Is the putty around older windows cracked or missing?
Are window sills sloping away from the building to shed water?
Are there signs of rot in timber frames?
Failed seals allow water to penetrate around openings, causing localised damp and potential timber decay.
The Internal Inspection: What to Check Inside
Once you've assessed the exterior, move inside to look for signs that winter has caused damage.
Walls and Ceilings
Check all rooms for:
Damp patches, especially on external walls
Water stains or discolouration on ceilings
Peeling wallpaper or bubbling paint
Cold spots that feel different from surrounding areas
Tide marks or salt deposits low on walls (indicating rising damp)
Mould growth in corners or around windows
Pay particular attention to rooms directly below the roof, rooms with external walls, and any areas where you've noticed problems before.
Windows
Condensation on windows is common in winter, but persistent moisture can indicate problems:
Black mould around window frames
Rotting timber on sills or frames
Water pooling on internal sills
Condensation between double glazing panes (indicating seal failure)
Damp patches on walls below or beside windows
Loft Space
If you have access to your loft, this is one of the most important areas to check:
Look for daylight coming through gaps in the roof
Check for water stains on timbers or felt
Feel for damp patches on the underside of the roof
Look for signs of condensation (moisture on timbers, mould growth)
Check that insulation is dry and hasn't been disturbed
Inspect around any roof penetrations (vents, pipes, aerials)
Problems in the loft often go unnoticed until they cause damage to ceilings below.
Basement and Lower Ground Floor
If your property has a basement or lower ground floor, check for:
Damp patches on walls or floors
Water ingress around windows or vents
Musty smells indicating hidden moisture
White salt deposits on walls
Mould growth
Basements in London properties are particularly prone to damp due to the clay soil, high water table in some areas, and often inadequate original waterproofing.
Behind Furniture
Move furniture away from external walls, especially in bedrooms and living rooms. Mould often grows unnoticed behind wardrobes, beds, and sofas pushed against cold walls. Check for:
Black mould on walls or the back of furniture
Musty smells
Damp or damaged wallpaper
Condensation marks
Common Problem Areas in London Properties
Certain features common to London homes are particularly vulnerable to winter damage and damp:
Victorian and Edwardian Terraces
These properties often have:
Solid walls without cavity insulation, making them prone to cold bridging and condensation
Original slate DPCs that may have failed or been bridged
Decorative features (cornices, bay windows) with complex junctions where water can penetrate
Parapet walls and flat roofs on rear additions that are prone to leaks
Cellars and basements with inadequate waterproofing
Converted Flats
Conversions often suffer from:
Shared walls and floors where responsibility for repairs is unclear
Altered ventilation patterns that increase condensation risk
Flat roofs on extensions with limited lifespan
Water penetration from units above
Inadequate insulation added during conversion
Bay Windows
Bay windows are notorious for damp problems:
Flat or low-pitched roofs above bays often leak
Lead flashing deteriorates and allows water in
Gutters behind parapets block easily
Complex junctions provide multiple entry points for water
Chimney Stacks
Disused chimneys are common sources of damp:
Flashing around the stack fails over time
Pointing deteriorates faster at height where exposure is greater
Rainwater enters through uncapped pots
Lack of ventilation causes condensation inside the flue
When to Call a Professional
Some issues you can identify yourself, but others need expert assessment. Consider calling in a professional if you notice:
Persistent or spreading damp patches that don't dry out as weather improves
Structural cracks in walls, especially if they're widening or accompanied by other movement
Extensive mould growth covering large areas or returning quickly after cleaning
Roof damage that you can't safely inspect from ground level
Damp affecting timber including floors, skirting boards, or structural elements
Rising damp symptoms such as tide marks and salt deposits low on walls
Basement water ingress that occurs repeatedly or in significant quantities
Any damp issue you can't identify the cause of without investigation
Why a Professional Damp Survey Matters
A DIY inspection can spot obvious problems, but identifying the root cause of damp often requires specialist knowledge and equipment.
Different types of damp (rising, penetrating, and condensation) look similar but require completely different solutions. Misdiagnosis leads to wasted money on ineffective treatments.
A professional damp survey provides:
Accurate Diagnosis
Using moisture meters, thermal imaging, and expert knowledge, a surveyor can identify exactly what type of damp you're dealing with and where it's coming from.
Root Cause Analysis
Surface symptoms often have hidden causes. A professional identifies whether the problem stems from failed DPCs, defective pointing, inadequate ventilation, or other issues.
Remediation Recommendations
Once the cause is identified, the surveyor recommends appropriate solutions, not generic treatments that may not address your specific problem.
Written Report
A professional report documents the findings, recommendations, and estimated costs. This is invaluable for planning repairs, negotiating with contractors, or supporting insurance claims.
Peace of Mind
Knowing exactly what you're dealing with, rather than guessing, allows you to prioritise repairs and budget effectively.
Simple Maintenance to Prevent Future Problems
Once you've addressed any issues from winter, regular maintenance helps prevent problems recurring:
Clean Gutters Twice a Year
Clear gutters in late autumn after leaves have fallen and again in spring. Check that water flows freely and downpipes aren't blocked.
Maintain Pointing
Repoint any damaged mortar joints before winter arrives. Use lime mortar on older properties to allow walls to breathe.
Keep Ground Levels Low
Ensure soil, paving, and decking are at least 150mm below the DPC level. Clear any debris that accumulates against walls.
Ventilate Your Home
Open windows daily, even briefly, to allow moisture to escape. Use extractor fans when cooking and bathing. Keep trickle vents open.
Address Small Problems Quickly
A cracked tile or blocked gutter is cheap to fix. Left unaddressed, the water damage that follows can cost thousands.
Annual Roof Inspection
Have your roof inspected professionally at least once a year, ideally in autumn before winter weather arrives. Early detection of problems prevents expensive repairs.
FAQs: Post-Winter Property Checks
How soon after winter should I inspect my property?
Early spring is ideal, once the worst of the winter weather has passed but before problems have time to worsen. March and April are good months to conduct a thorough inspection.
Can I do a damp inspection myself?
You can identify obvious signs of damp, but diagnosing the type and cause often requires professional equipment and expertise. If you find damp, a professional survey is recommended to ensure the right solution.
What's the difference between condensation and penetrating damp?
Condensation forms when warm, moist air meets cold surfaces. It's typically worse in winter, affects corners and windows, and often causes black mould. Penetrating damp comes from water entering through defects in the building envelope. It's often worse after rain and appears as localised wet patches.
How much does it cost to fix damp problems?
Costs vary enormously depending on the cause and extent. Clearing gutters might cost under £100. Repointing a wall could be several hundred pounds. Major damp proofing or structural repairs can run into thousands. A professional survey helps you understand what you're facing before committing to work.
Should I worry about small cracks after winter?
Small cracks are common and often harmless, caused by normal building movement. However, cracks that are widening, stepped (following mortar joints), or accompanied by other symptoms warrant professional assessment.
My home smells musty but I can't see any damp. What should I do?
Musty smells indicate hidden moisture, possibly behind walls, under floors, or in cavities. A professional survey using thermal imaging and moisture meters can locate the source without destructive investigation.
Book Your Post-Winter Damp Survey
Henderson Wood provides expert damp surveys across all London boroughs. Our RICS-compliant inspections identify exactly what's causing damp in your property and recommend effective solutions.
Whether you've spotted warning signs after winter or simply want peace of mind about your home's condition, we deliver thorough assessments and clear, actionable reports.
Don't let winter damage become a bigger problem. A professional survey now can save you significant expense and disruption later.