How to assess a roofing contractor before work starts

The roof covering interacts with the structure, insulation, waterproofing layer and drainage. A tradesperson should understand these relationships even when their contract covers only part of the works. They must be able to identify a substrate problem or a missing prepared detail before it is covered up.

During the conversation, ask about the junction at the chimney, the eaves and the window. A substantive answer refers to the roof build-up and the documentation. A general assurance that it is always done the same way does not explain the differences between products. Modular tile-effect metal roofing and sandwich panels require different solutions.

Ask for the installation instructions to be identified and for the elements affecting the scope of works to be discussed. Pitch, support, laps and fixings matter. The designation T18 or T35 does not define all these parameters. The contractor should use the data for the actual profile.

With large panels, knowledge of transport and lifting is also needed. Incorrect handling can damage the component before installation. Experience with a similar material is useful but does not remove the need to read the requirements of the current product. The instructions should be available to the crew on site.

The scope covers specific layers, flashings, fasteners, accessories and preparatory work. It must be established who is responsible for measurement, ordering and unloading. It is worth recording how additional repairs revealed after removal are settled. This helps avoid disputes in the middle of the work.

A price per metre without a description of the scope can be misleading. One quote may include full drainage, while another covers only laying the sheet metal. Also compare protection of the building against rainfall during the works. The schedule should allow for weather and the possibility of safely closing successive stages.

For coated sheet metal, cutting tools approved by the manufacturer are used. An angle grinder can damage the coatings through heat and hot swarf. Good organisation includes removing particles promptly and protecting the material during handling. Tidiness here is directly linked to durability.

Checking the seating of the screws and the support of the sheets is important. Overtightening is not proof of solidity. It can destroy the seal or deform the surface. A tradesperson can explain which fasteners fix the covering to the structure and which connect adjacent components.

Yes, because working on a roof requires protecting people and the surroundings. The contractor should plan access, workstations and material transport. Accidental walking on unsupported components can harm both the person and the covering. Speed should not force such shortcuts.

Protecting openings and the area below the works is also important. With sandwich panels or long sheets, wind conditions during lifting must be monitored. This is part of work organisation and should be included in the quote. It should not appear only after the material is delivered.

If the substrate is uneven, the timber damaged or the detail inconsistent with the design, the problem must be reported before covering. The proper response includes a description, photos and agreement on how to proceed. Independent changes to load-bearing components are not an acceptable way to speed up installation.

The same applies to a damaged delivery or a missing flashing. It is better to agree on a matching material than to replace it with a random component. The contractor does not have to know the answer to every unusual situation immediately. They should, however, know when the designer’s or system supplier’s data is needed.

Photos of the layers before covering, a description of the materials used and a completion record are useful. The handover should cover junctions, fixings, drainage and tidying of the roof slope. Any defects and the deadline for remedying them must be recorded. A mere notification that installation is complete is too general.

Also ask for usage and maintenance recommendations. The owner should know how to inspect the roof and which interventions to agree. References from similar projects help assess the craftsmanship, but are best combined with a conversation about details. Good cooperation is based on clear agreements and work that can be checked.

Before signing the contract, choose one difficult detail from your own project and ask the contractor to discuss it. The way support, sealing and the sequence of works are explained will show more than a general declaration of many years’ experience.

A good roofer is recognised by pertinent questions, knowledge of the system and careful conduct of the work. Documentation and a readiness to stop a stage when there is a substrate error also matter. A reliable quote and agreed handovers help assess quality even before the first sheet is on the roof.