Can You Re-Roof a Concrete Sectional Garage?

A sectional garage is assembled from precast concrete panels that bolt to concrete posts. The walls are a series of tall slabs slotted between uprights, and the roof is a set of corrugated sheets resting on timber or concrete purlins, the rails that run along the building and carry the sheets. The roof pitch is shallow, so water leaves slowly and every lap and bolt hole matters.

What can go wrong with the roof?

Sheets crack where someone has stepped on them. Fixing bolts rust and let go, and the bolt holes elongate, so a sheet rattles and lifts in wind. Moss grows in the corrugations, holds water and speeds the ageing of the surface. Sometimes the purlins have cracked or the posts have shifted, so the sheets no longer sit flat on their supports.

Repair is possible when the sheets are sound and only a few fixings have failed. Where the sheets are cracked across several bays, or fibres have started to show on the surface, a full replacement is the better buy than patching each crack.

Our page on leaking garage roofs explains how we trace a leak before we recommend a repair or a new covering.

Many sectional garages put up before the turn of the century were roofed in asbestos cement sheet. HSE says that if a building dates from before 2000, you should presume asbestos is there until shown otherwise. Its guidance A14 describes these roofs as always fragile, which rules out stepping on one without crawl boards and edge protection.

Do I have to remove it?

Not necessarily. Sound asbestos cement can stay in place, and an overlay may be an option. If the sheets do have to come off, HSE classes careful removal without breaking the material up as non-licensed work. Breaking the sheets up substantially, or dropping them from the roof, becomes notifiable non-licensed work, which carries extra duties. Waste from asbestos sheets gets two layers of wrapping and a label, and travels under a consignment note. An ordinary skip is not an option.

The date on the garage is only a clue. Sheets that look identical can be asbestos cement or modern fibre cement, so the material is confirmed before a price is written.

MyJobQuote gives an average of around £2,750 for asbestos roof removal, with a survey typically £325 (Sep 2026). We help you sort out the check first, and our asbestos garage roof removal guide sets out the steps in more detail.

Once we know the old sheets are safe to deal with, the new covering is chosen to suit the frame and the slope. Lightweight options suit these garages well, because the precast walls and the roof rails were designed for sheets rather than tiles.

Which new sheets suit a sectional roof?

Fibre-cement and coated steel are both used. Fibre cement without asbestos looks close to the original and fits the existing profile. Coated steel box-profile is lighter again, as covered on our box-profile garage roof page, and a plastic-coated metal sheet can include an anti-condensation backing.

Whatever goes on, the sheets must overlap properly. Each end lap needs enough cover, and each side lap needs to sit tight on its neighbour. Fixings go through the crowns of the corrugations with sealing washers, and the gable ends and eaves get proper trims, because the edge is where wind grips first.

Gutters on sectional garages are often fixed to brackets bolted into the concrete. We check the brackets and the fall as part of the visit and replace what has failed, so water leaves the roof cleanly.

A sectional garage is often small, but access can be awkward. Many stand at the end of a drive, close to a boundary, with a fence on one side and a house wall on another. That decides whether we need a tower, a cherry-picker style lift or a simple ladder, and whether sheets can be handed down safely.

What decides the price?

Four things. The roof area is one. The material coming off is another, since asbestos cement adds handling, wrapping and disposal. The new covering is the third, and access is the fourth. For scale, MyJobQuote (Oct 2026) lists £750 to £3,500 for replacing a garage roof, and a sectional garage with sound sheets and easy access is the simpler end of that kind of job.

The visit produces photos of the sheets, bolts and purlins, and a single written total once the material is confirmed. Should the sheets prove to be asbestos cement, we explain what that changes and which route we suggest. You can also see the wider picture on our garage and asbestos roofs page.