The roof is arguably the most important element of any property. As building surveyors conducting RICS surveys across Cardiff and South Wales, we pay particular attention to roof condition during our inspections. A failing roof can cause thousands of pounds of damage and make a property virtually unsellable.
Over my 12 years as a chartered surveyor specializing in residential properties, I've inspected thousands of roofs. This guide explains what we look for, common problems in Cardiff properties, and how our inspections protect homebuyers.
Why Roof Inspections Are Critical
A sound roof protects everything beneath it. Roof failures lead to:
- Water penetration damaging ceilings, walls, and contents
- Timber decay in roof structures
- Damaged insulation reducing energy efficiency
- Mold and damp problems throughout the property
- Expensive emergency repairs if catastrophic failure occurs
- Difficulty selling or mortgaging the property
During our Level 2 RICS home surveys and comprehensive building surveys, roof inspection is a priority. We identify problems early, allowing you to factor remedial work into your purchase decision.
How We Inspect Roofs During Surveys
Our inspection approach depends on the survey type you've commissioned:
Level 2 HomeBuyer Report Roof Inspection
During a Level 2 RICS home survey, we inspect roofs from ground level using high-powered binoculars. This allows us to see:
- Overall roof covering condition
- Missing or slipped tiles/slates
- Ridge tile condition
- Chimney stack condition
- Lead flashings where visible
- Guttering and downpipes
- General roof shape (sagging or distortion)
We also access roof spaces where safely accessible from inside the property to inspect:
- Roof timbers for decay or insect attack
- Evidence of leaks or water penetration
- Insulation levels
- Water tanks and pipework
- Party walls in terraced properties
Level 3 Building Survey Roof Inspection
Our comprehensive building surveys include more detailed roof inspection. We:
- Access roof spaces from all available entry points
- Inspect roof timbers thoroughly with moisture meters
- Check for structural adequacy of roof framing
- Document any previous repairs or alterations
- Assess ventilation adequacy
- Photograph defects for the report
While we don't walk on roofs (too dangerous and could cause damage), our ground-level inspection combined with roof space access provides comprehensive assessment.
Common Roof Problems in Cardiff Properties
Cardiff's housing stock is diverse, but we regularly encounter these roof issues:
1. Welsh Slate Roof Deterioration
Many Victorian and Edwardian properties in Cardiff have original Welsh slate roofs. While these are high-quality, they're now 100-150 years old.
Common slate roof problems:
- Nail fatigue: Original iron nails corrode, causing slates to slip
- Cracked slates: From weathering, impact, or poor repairs
- Missing slates: Blown off during storms
- Delaminating slates: Splitting in layers
- Poor quality replacements: Cheaper slates mixed with originals
A typical Victorian terrace in Roath or Canton needing complete re-slating costs £10,000-15,000. Our survey reports help you budget for this major expense.
2. Concrete Tile Issues
Properties built between 1950-1990 typically have concrete tiles. These last 40-60 years before requiring replacement.
Concrete tile problems we find:
- Slipped or broken tiles
- Tile nibs (the part that hooks over battens) breaking off
- Ridge tiles becoming loose
- Moss and algae growth (indicates poor drainage)
- Mortar deterioration under ridge tiles
3. Flat Roof Problems
Many Cardiff properties have flat roof extensions, dormers, or rear additions. Flat roofs are problematic:
- Limited lifespan: Traditional felt roofs last only 10-20 years
- Ponding: Standing water indicates inadequate falls
- Blistering: Trapped moisture in felt layers
- Cracking and splitting: From UV damage and movement
- Failed flashing: Where flat roof meets walls
Flat roof replacement costs £80-120 per square meter. Modern GRP (fibreglass) systems last 25-30 years and are worth the investment.
4. Lead Flashing Failures
Lead flashings seal joints between roofs and walls, around chimneys, and in valleys. In Cardiff's wet climate, failed flashings cause serious water penetration.
Lead flashing issues:
- Cracked or split lead from thermal movement
- Inadequate overlap or fixing
- Lead theft (unfortunately common)
- Poor quality repairs using inappropriate materials
- Corroded lead (particularly on older properties)
5. Ridge Tile Problems
Ridge tiles cap the apex of pitched roofs. They're vulnerable to storm damage and deterioration.
Ridge issues we identify:
- Loose or missing ridge tiles
- Deteriorated mortar bedding
- Missing or damaged ridge vents
- Poor quality pointing repairs
- Mechanical fixings (clips) failing
6. Chimney Stack Defects
Most period properties in Cardiff have chimneys. Even unused chimneys need maintenance.
Chimney problems:
- Loose or missing chimney pots
- Deteriorated mortar joints and pointing
- Leaning or unstable stacks
- Cracked render
- Missing or inadequate capping
- Failed lead flashings around base
Chimney repairs require scaffolding or access equipment, making them expensive. Budget £2,000-5,000 for major chimney work.
7. Roof Timber Decay
When we access roof spaces, we carefully inspect timber condition:
- Wet rot: From active leaks or condensation
- Dry rot: Less common but more serious fungal decay
- Woodworm: Beetle larvae boring through timber
- Previous water damage: Staining indicating historic leaks
We use moisture meters to measure timber moisture content. Readings above 20% indicate problems requiring investigation.
8. Inadequate Roof Ventilation
Modern insulation standards can cause condensation in roof spaces if ventilation is inadequate.
Ventilation problems:
- No or insufficient soffit vents
- Blocked ventilation pathways
- Insulation blocking eaves ventilation
- No ridge ventilation on newer roofs
- Condensation on roof timbers and felt
9. Poor Quality Repairs
We frequently find inappropriate roof repairs:
- Cement-based fillers instead of proper replacements
- Silicone sealant as temporary waterproofing (becomes permanent)
- Mismatched tiles or slates
- Temporary tarpaulins left in place
- DIY repairs that don't address underlying problems
10. Structural Issues
Serious problems we look for include:
- Sagging roof lines indicating timber failure
- Spread or bowing walls affecting roof structure
- Inadequate support for roof loads
- Movement in party walls
- Distorted roof shapes
What We Document in Roof Inspection Reports
Our survey reports include detailed roof information:
Roof Description
- Roof type (pitched, flat, combination)
- Covering material (slate, tile, felt, etc.)
- Approximate age and condition
- Chimney stacks present
- Roof lights or dormers
Condition Assessment
We use a traffic light system:
- Condition 1 (Green): No repair needed
- Condition 2 (Amber): Repairs needed but not urgent
- Condition 3 (Red): Urgent repairs required
Identified Defects
Specific problems found with:
- Clear descriptions
- Likely causes
- Consequences if not addressed
- Recommended actions
- Approximate costs
Professional Guidance
We provide professional guidance on:
- Urgency of repairs
- Whether specialist contractors needed
- Likely lifespan of current roof
- Future maintenance requirements
- Impact on property value
Real Example: Semi-Detached House in Llanishen
Last month, I surveyed a 1960s semi-detached house in Llanishen for first-time buyers. From ground level, the concrete tile roof looked acceptable.
However, roof space access revealed:
- Historic water penetration at the valley (where roof slopes meet)
- Several roof battens showing signs of rot
- Inadequate ventilation causing condensation
- Insulation blocking eaves ventilation
- Evidence of active leaks during rain
From outside, I then identified:
- Cracked valley tiles
- Failed valley lead work
- Several slipped tiles
Repair cost estimate: £4,500 for valley repairs, new lead work, tile replacement, and ventilation improvements. Without the roof space inspection, these problems would have remained hidden until they caused ceiling damage.
When to Commission a Specialist Roof Survey
Sometimes our initial inspection identifies issues requiring specialist investigation:
Structural Concerns
If we find significant sagging, movement, or timber defects, we may recommend a structural engineer's report.
Flat Roof Condition
For complex flat roof systems, a specialist roofing contractor may need to conduct tests for moisture within the roof construction.
Hidden Defects
If we suspect problems we can't fully assess (perhaps due to access limitations), we'll recommend further investigation.
Our survey reports clearly state when additional specialist surveys are advisable.
Roof Replacement Costs in Cardiff
Understanding costs helps you budget:
- Victorian terrace re-slate: £10,000-15,000
- Semi-detached house re-tile: £6,000-10,000
- Flat roof replacement (20m²): £2,000-3,000
- Ridge tile re-pointing: £800-1,500
- Chimney repairs: £2,000-5,000
- Lead flashing replacement: £500-2,000 per area
- Roof timber repairs: £1,500-5,000 depending on extent
These are approximate costs for properties in Cardiff. Actual costs depend on property specifics, access, and material choices.
Roof Maintenance Advice
To protect your investment, we recommend:
- Annual visual inspection from ground level
- Clear gutters and check downpipes twice yearly
- Address minor issues promptly before they worsen
- Have professional inspections every 3-5 years
- Budget for eventual roof replacement
- Maintain roof space ventilation
- Check after severe storms
The Value of Professional Roof Inspection
Many property buyers consider skipping professional surveys to save money. However, roof problems are expensive:
- A £500-800 homebuyers survey could identify a £15,000 roof replacement need
- Our reports give negotiating power with sellers
- You can budget for necessary work
- Avoid buying properties with catastrophic roof failures
- Understand maintenance requirements before purchase
As RICS chartered surveyors, we've seen countless buyers save tens of thousands of pounds through our roof inspections.
Frequently Asked Questions
Can surveyors walk on roofs during inspections?
No. It's dangerous and could damage the roof covering. Our ground-level inspection with binoculars, combined with roof space access, provides comprehensive assessment without these risks.
What if the roof space isn't accessible?
We note this limitation in our report. While we can still assess external roof condition, internal inspection is valuable. We may recommend making access available for further inspection.
Should I fix roof problems before selling?
It depends. Major issues will affect sale price and mortgageability. Minor issues might be factored into negotiations. Our surveys help sellers understand what buyers' surveyors will find.
How often should roofs be replaced?
Welsh slate: 100-150+ years; Concrete tiles: 40-60 years; Clay tiles: 60-100 years; Flat felt roofs: 10-20 years; GRP flat roofs: 25-30 years. Our surveys assess remaining lifespan.
Can roof problems affect my mortgage?
Yes. Serious roof defects may cause lenders to refuse mortgages or require repairs before completion. Our surveys identify problems early in the transaction.
Book Your Professional Survey
Don't risk buying a property with hidden roof problems. Our experienced team of building surveyors provides thorough roof inspections as part of comprehensive RICS surveys across Cardiff and South Wales.
We deliver detailed survey reports in a timely manner, with clear professional guidance on roof condition, necessary remedial work, and realistic costs.
Contact Cardiff Surveyors today for your online quote. We provide professional surveys for residential properties across all areas of Cardiff, Swansea, Newport, Vale of Glamorgan, and surrounding areas of South Wales.
Regulated by the Royal Institution of Chartered Surveyors. Providing expert roof inspections and impartial advice since 1998.