Roof surveys: how surveyors check roof condition and repair costs

Other than firm, strong foundations, the roof is the most important part of any building which is why roof condition is assessed as standard in every RICS Level 2 and Level 3 survey. For an overview of all issues a survey can flag, see our common survey problems guide.

Here, Surveyor Local looks at what roof surveys cover in detail, from the outer structure to the roof space, and what buyers can expect to find in the report. This focuses on pitched roofs; flat roofs are handled differently. 

• Roof condition is checked as standard in every RICS Level 2 and Level 3 survey, covering the outer covering, structure, chimneys, flashings, gutters and roof space.
• No surveyor will walk on a roof. Checks are made from ground level using binoculars, pole cameras and drones, and from inside the roof space where access is available.
• Common defects include damaged or missing tiles, failed flashings, sagging timbers, blocked gutters and condensation in the roof space.
• Spray foam insulation is a known concern for mortgage lenders — many will require a specialist report or its removal before they will lend.
• Roof repair costs range from around £100 for minor tile work to £15,000 or more for a full replacement, depending on size and materials.
• A Level 3 survey is recommended for older homes or where roof condition is a known concern.

The primary focus of any roof inspection is stability and structural integrity, water tightness and general safety. A roof survey covers both the external parts and the internal structure, as long as it is safely accessible.

The report will flag evidence of damage, including sagging, leaks, damp, water ingress, rot and any missing materials such as flashings and tiles. From this, buyers get a clear picture of the repairs needed to protect the roof, along with an estimate of its remaining lifespan.

Roof inspections cover not only the main roof coverings but the state of chimney stacks, fascia boards, soffits, flashings and any fittings such as satellite aerials and skylights.

No surveyor will walk on a roof for health and safety reasons. The roof inspection relies on binoculars, extendable ladders, drones fitted with cameras and pole-mounted cameras to observe and identify any defects. Artificial intelligence is increasingly used to help interpret images and verify concerns that might not be immediately obvious.

You have an input to the process too. If you notice the roof looks tired, shows obvious signs of wear or simply looks old, flag this before the survey begins so that way, any areas of concern will get closer attention.

The different issues that can be identified with a problematic pitched roof can be categorised as follows:

Roof covering

Roof coverings whether slate, tile or metal sheets such as aluminium, are checked for cracks, tears or holes, and for any that are missing or have slipped. Any of these faults can allow rainwater to penetrate inside.

Moss growth is a key indicator of potential damage. Its roots can penetrate the roof covering, and because moss retains moisture, it can lead to leaks and damp over time.

Primary structure

Visible sagging is the clearest sign of structural concern and is usually caused by failure of the timber trusses or rafters. These are checked for rot, breaks or other defects. The structural supports are sometimes too weak for the weight of the covering above, which produces that visible sag when viewed externally.

Chimneys and gable walls

The mortar and brickwork of any structure at roof level is checked for cracks and perishing. Chimney pots are confirmed stable, since high winds or extreme weather could cause fragile pots to come loose and fall into the roof structure.

Flashings

These are the (usually lead) connector sheets between angles on the roof such as between a chimney stack or skylight and the main roof. Any signs of perishing or cracking are noted, as these allow water to penetrate inside.

Rainwater management

Gutters and drainpipes from the roof down to the drain are checked for blockages, leaks, missing elements or, where the material is metal, corrosion and holes. In older structures, asbestos may have been used as a roofing material and this will be raised as a query where relevant, though nothing will be scraped or removed for health and safety reasons.

Roof construction details

Fascias, soffits (both part of the eaves) and ridge tiles are examined for evidence of damage.

Internal roof space

This is where damp makes itself most apparent through staining of the wooden structure, dampness, wood rot and black mould. Condensation is also checked, with blocked ventilation and inadequate roof insulation among the most common contributing factors.

Insulation

The survey notes the type and condition of roof insulation whether spray foam, fibreglass roll or otherwise and flags any concerns about its age and effectiveness.

All roofs need regular maintenance to avoid minor wear compounding into more serious damage. The report will identify which areas need the most attention.

The difference between repairs and full replacement is significant which makes understanding roof condition one of the most useful things a survey can tell buyers.

For a detailed roof survey, the report will assess condition and highlight which findings need addressing now or in the near future, with advice on the type of work required: repair, partial replacement or full replacement.

Repair costs depend on the type and extent of work involved. As a rough guide for UK homes:

• Replacing broken, loose or missing roof tiles: from around £100
• Repointing ridge tiles or flashings: typically £300-£800
• Repairing or replacing gutters: £200-£600
• Addressing a sagging roof or significant structural repair: £3,000-£4,000 or more
• Full roof replacement: highly variable, but expect £5,000-£15,000 for an average semi-detached home

Costs also depend on materials, particularly for listed buildings or conservation areas where like-for-like sourcing is required. Location matters too as city centres and the South East carry higher premiums.

Waste disposal, skip hire and scaffolding should all be factored in on top. As a general rule, repair is cheaper than replacement, but patching a deteriorating roof may only delay the inevitable. The best advice is to consult an expert and seek several estimates from reputable contractors before committing. If anything in the report needs clarifying, do ask once it has been delivered.

Yes, in most cases it does.

Mortgage lenders will require a property to be watertight and structurally sound. Significant defects flagged in the survey, active leaks or non-standard construction materials can all cause a lender to withhold funds or decline to lend.

There are four areas that tend to cause concern:

Flat roofs - water pooling and the shorter lifespan of flat roof materials make these higher risk in lenders' eyes. Signs of wear, or materials with a limited life such as felt, can lead to a retention or refusal to lend.

Spray foam - once seen as a low-cost treatment, spray foam is sprayed into the roof space between the trusses. It has since been found to trap moisture, causing timber rot that can lead to structural failure if untreated. The difficulty of accessing roofing materials once spray foam is in place means lenders will often require a specialist report and in some cases removal before agreeing to lend.

Damaged or ageing roofs - defects with chimneys, flashings, felt, roofing materials and timbers are the most common source of mortgage complications. Where a home has been rendered uninhabitable or poses a structural risk, lenders are unlikely to proceed without remediation.

Non-standard construction - thatching, corrugated metal or materials such as asbestos may cause a lender to pause until an expert report has been completed.

If your lender has raised concerns, the survey findings give you grounds to renegotiate the price or agree with the seller on how remediation costs will be shared. The survey and any specialist reports provide the information needed to make the right decision or to walk away.

When you are buying a house and want to know the condition of the property, you will want to know which survey is the best choice.

The RICS Level 2 survey will provide a reasonable amount of detail. The external roof is assessed from ground level using binoculars and long camera lenses to examine any areas of concern. The loft space is also checked from the hatch where accessible though boards are not lifted and materials are not removed. All findings are noted in the report.

The RICS Level 3 survey is much more comprehensive, with a thorough roof space inspection and a more detailed external review. Throughout both the internal and external roof areas, the report will highlight any need for specialist investigation and provide evidence for that recommendation. The Level 3 survey also gives an estimate of the likely cost of any remediation.

In both cases, no surveyor will walk on the roof.

The report will note the remaining lifespan of the roof and its materials, and will recommend seeking estimates from appropriate contractors for any remedial work.

For older properties or period homes, or any purchase where roof condition concerned you at viewing, a Level 3 survey is worth the additional cost.

Not sure which survey is right for your property?  Compare RICS surveys.

A RICS Level 2 or Level 3 survey is the right first step for any property purchase. Get a free quote or call our friendly team on .