A roof can look tidy from ground level and still have defects that lead to leaks, loose tiles and expensive internal damage. This roofing workmanship checklist gives homeowners, landlords and property managers a practical way to assess completed work, raise concerns early and understand what a professional standard should look like.
It is not a substitute for safe roof access or an expert inspection. Never climb onto a roof to check a contractor's work. A reputable roofer should be happy to explain the job, show clear photographs of inaccessible areas and deal with any reasonable snagging points before the work is signed off.
Start with the agreed scope of work
Good workmanship begins before the first tile is lifted. Compare the completed work with the written quotation or specification. Whether the job was an emergency repair, chimney repair, gutter replacement or complete re-roof, you should be clear about what was included and what was found once work began.
Check that the contractor has explained any additional work, such as rotten battens, failed underlay, damaged leadwork or defective flashing. These issues are often hidden until the roof covering is opened up, particularly on older properties. They may be genuine and necessary, but they should not come as a surprise at the final invoice.
For planned re-roofs, confirm the agreed tile or slate type, colour, roof ventilation arrangement, insulation work if applicable, and the areas being renewed. For repairs, establish exactly which defect was addressed and whether neighbouring areas were inspected for related damage.
Roofing workmanship checklist for the roof covering
From the ground, and from photographs supplied by the contractor, look for a roof covering that appears straight, consistent and properly aligned. Tile and slate roofing should follow even lines, without obvious dips, raised corners or irregular gaps. A few variations are normal on an older roof, especially where materials have weathered over decades, but newly completed sections should not look haphazard.
Tiles and slates should sit securely and overlap correctly to shed water down the roof. Broken, cracked or poorly matched replacements can be more than a cosmetic issue. They may allow wind-driven rain beneath the covering or create a point where frost damage develops.
Pay particular attention to the ridge and hip tiles. These are exposed areas and must be firmly fixed, aligned and weatherproofed. Where a dry-fix system has been installed, components should be secure and neatly fitted. Where mortar has been used, it should be sound, well-shaped and free from excessive smearing over tiles.
On a complete re-roof, ask for photographs showing the underlay, battens and roof structure before the covering was installed. These layers control water drainage beneath the tiles and provide the fixing base for the roof covering. You may not see them after completion, so photographic evidence is useful.
Check flashings, leadwork and roof junctions
Most leaks occur at junctions rather than in the middle of a roof slope. Chimneys, valleys, dormers, rooflights, parapet walls and abutments all need careful detailing. This is where workmanship matters most.
Leadwork should be neatly dressed, securely fixed where required and shaped to direct water away from the building. It should not be split, lifted or simply covered with large amounts of sealant. Sealant can be appropriate for limited detailing and minor repairs, but it is not a long-term substitute for correctly formed flashing.
At chimneys, check that flashing and soakers are present where needed, and that mortar work around the stack is sound. Cracked chimney pointing, loose pots and failed flaunching can allow water into the roof space even after nearby tiles have been repaired. If chimney work was part of the job, the contractor should have addressed the specified defects rather than focusing only on the roof covering.
Valleys need particular care because they carry a high volume of rainwater. They should be clear of mortar debris, broken tile fragments and offcuts. The valley lining should appear continuous and properly supported, with tiles cut cleanly along its edges.
Inspect gutters, fascias and drainage
Roofing work is only as effective as the drainage route below it. Water should leave the roof, enter the gutters and run freely to the downpipes without overflowing onto brickwork, timber or paths.
Look along the gutter line for a consistent fall towards the outlet. A small amount of standing water may be visible immediately after rain, but persistent pooling can indicate incorrect brackets, poor alignment or blockage. Gutters should be firmly attached and joints should not drip.
If fascias and soffits were replaced, they should be straight, securely fixed and neatly finished around corners and eaves. Ventilation openings must not be blocked during the work. Adequate roof ventilation helps manage condensation in the loft space, which is especially relevant after insulation improvements or a full roof renewal.
It is also worth checking that downpipes discharge into the correct drain or gully. A newly repaired roof can still cause problems if rainwater is being directed against the building or allowed to soak close to the foundations.
Look inside the loft after rain
A visual check from inside the loft can reveal issues that are not obvious outside. Choose daylight or, better still, inspect after steady rain. Do not disturb insulation or walk on ceiling joists unless you can do so safely.
Look for fresh water marks, dripping, wet insulation, mould growth or daylight visible through the roof covering. Old staining does not automatically mean the new work has failed, but it should be discussed if you are unsure whether it is historic or recent.
Also check for adequate airflow. A roof that has been made more airtight without appropriate ventilation may develop condensation, even where rainwater is not getting in. This is one reason a proper assessment should consider the whole roof system, not just the tile or slate visible from outside.
Judge the site finish as well as the roof
A professional job should leave the property safe and orderly. Scaffolding and access arrangements should be removed when agreed, and the area around the property should be cleared of broken tiles, nails, mortar and packaging. This matters particularly for homes with children, shared driveways, commercial entrances or parking areas.
Ask whether waste disposal was included in the quotation and ensure any skips, scaffolding or protective measures have been dealt with properly. Check windows, render, solar panels, conservatory roofs and paving for accidental damage or mortar staining before the contractor leaves site.
Documentation is part of a good finish too. Retain the quotation, invoice, photographs, product information and any guarantee provided. For landlords and commercial property managers, these records make future maintenance planning and reporting much easier.
When to raise a concern
Raise concerns promptly if you see slipped tiles, open gaps, leaking gutters, poorly finished flashing, damaged property or water entering the loft after the work. Take dated photographs and describe the issue clearly. Avoid arranging another contractor to alter the work before giving the original contractor a fair opportunity to inspect it, unless there is an immediate risk of damage or danger.
Some points are matters of appearance, while others require urgent action. A cracked tile near a chimney may be a straightforward snag. Water running into electrics, a loose ridge tile after high winds or an active leak during heavy rain should be treated as an emergency.
For urgent defects, Armstrong Roofing & Building Limited provides a 24-hour emergency response, with no call-out charge and free quotations for the work required. A prompt inspection can prevent a small failure at a roof junction from becoming damaged ceilings, insulation and internal finishes.
A well-finished roof should give you confidence when the weather turns. If anything about the workmanship looks unclear, ask for an explanation and evidence before accepting the job - good contractors expect those questions and deal with them properly.