What does a roofer do, and which parts of the roof are they responsible for?

Before laying the first sheet, the roofer checks the dimensions and shape of the roof slope, particularly the eaves line, the diagonals and the positions of the supports. This does not take the place of the structural engineer’s work. It does mean reporting visible discrepancies or conditions that prevent correct installation while the supports are still accessible.

Discuss the exact product as well. Long tile-effect sheets cut to length, small modules and sandwich panels each require different preparation. Use the instructions for the version being installed. Two sheets with similar profiles may still need different fixing positions and overlaps.

The work may cover the underlay, counterbattens, battens, sheets and flashings. Gutters, service penetrations, roof steps and chimney access platforms are often involved too. List what the client will supply and what the contractor will bring. A single missing fitting can stop work or tempt a crew to improvise a substitute.

For a renovation, agree separately on stripping the old covering and protecting the exposed building. Specify who removes the waste and how repairs discovered after stripping will be priced. An item labelled simply “fit metal roofing” leaves room for conflicting expectations, especially around complex flashings.

Straight rows are only one sign of good workmanship. A roofer checks drainage paths, ventilation, overlaps, seal compression and the position of flashings. An undertightened screw may leave the hole unsealed; overtightening can distort the washer or the sheet. Counting screws alone tells you little about the seal.

Remove drilling swarf before it rusts on the coating. Lift sheets apart instead of dragging them across one another, and use cutting tools suitable for coated steel. Sparks or excessive heat at the cut edge can damage the protective finish without leaving a conspicuous defect on handover day.

The crew needs measuring equipment and tools for forming flashings as well as cutting and fixing tools. Plan how the material will reach the roof safely. Long sheets need adequate support along their length: lifting at a few arbitrary points can permanently distort the profile and leave the joints difficult to close.

Fixing a sheet to its support and stitching two sheets together at a lap are different jobs. For sandwich panels, the support material and the total thickness to be fixed also matter. No single screw suits every connection. Ask how the roofer selects the fasteners and whether they work to the instructions for your product.

Ask to see comparable roofs, ideally after several seasons in service. A plain gable roof involves different work from a roof with dormers and intersecting slopes. A distant photograph reveals little about the valleys, chimney flashings or joints in the underlay.

Discuss difficult details as well as price. The contractor should be able to explain the sequence of work and the conditions needed to proceed. Agree how changes will be reported and stages documented. A reliable roofer allows for the weather and does not promise that the same method will suit every sheet profile.

Ask what happens to stored material during a break. A stack of sheets under a tightly closed tarpaulin can retain moisture. A careful contractor plans a storage area, separates damp sheets and observes the deadline for removing protective film. Handling on the ground can affect the roof long before the first screw goes in.

Check that the flashings and drainage are complete and that the agreed accessories are present. Look for scratches and swarf on the coating and establish whether the protective film came off on time. For concealed details, installation photographs should show the material and how the key connections were made.

Finally, discuss inspections and where and how the roof may be accessed. Keep the delivery specification, instructions and agreed changes. A weathertight roof depends on design, materials and workmanship working together. Clear responsibilities make handover easier and help trace the cause if a problem appears later.