Independent comparisons. We may earn from shop links. More info

How to fit corrugated iron sheets

Updated: 23 October 2026

The sheets are on the ground and the shed slope is only a little longer than 110 cm. How to fit corrugated iron sheets on a small roof means a side lap, an end lap if one sheet will not reach, a fixing on the crest, and your weight kept off the steel. These amazon.co.uk packs do not state a lap distance or a minimum pitch, so do not promote a trade figure into a rule for 0.25 mm. Prices stay on the [corrugated iron sheets comparison](/hub/diy-supplies/corrugated-iron-sheets). Peter F. used those listings and published UK fitting notes. We did not drill a roof. A qualifying purchase can earn a commission at no extra cost to you.

The sheets are on the ground and the shed slope is only a little longer than 110 cm.

Our top picks

Harbour Housewares Harbour Housewares anthracite 14-sheet pack

Best overall

Harbour Housewares Harbour Housewares anthracite 14-sheet pack
7.4/10about £57.99
View offer
Mondeer Mondeer dark grey 14-sheet pack

Best value

Mondeer Mondeer dark grey 14-sheet pack
7.3/10about £53.99
View offer
Warmfay Warmfay black 24-sheet pack with screws

Alternative

Warmfay Warmfay black 24-sheet pack with screws
5.7/10about £73.99
View offer
On this page
  1. 1.Before you go up
  2. 2.Overlaps
  3. 3.Screws and washers
  4. 4.Cutting and swarf
  5. 5.When you should not do this yourself

Before you go up

A 110 × 46 cm sheet is a rectangle of steel, not of finished roof. A longer slope needs an end lap, and a second sheet across needs a side lap. None of the six listings states that lap. Thickness and face area are on the corrugated iron sheets buying guide. A rotten batten will not hold a screw. If you cannot tell what the old covering is, stop. Treat the roof as fragile until you know it is not.

Overlaps

The side lap shares a corrugation. The end lap is how an upper sheet covers the one below. These packs print no cover width. Cladco’s own note asks for at least two corrugations and 10° on that product. Corozinc’s 8/3 guide asks for at least one corrugation and an end lap of at least 300 mm. You cannot average those into a lap for a 46 cm, 0.25 mm panel. Two 1.10 m sheets on a 2 m slope already overlap by 200 mm. The listings also do not say which way the lap should face the wind.
Harbour Housewares Harbour Housewares anthracite 14-sheet pack

Testsieger

Harbour Housewares Harbour Housewares anthracite 14-sheet pack
7.4/10about £57.99
View offer

Screws and washers

On a wavy sheet, the guides used here put the screw on the crest and tell you not to crush the washer flat. Box profile is often fixed in the valley. That split is on corrugated vs box profile. Warmfay states 400 screws and washers, and one review says they were too small. Try one crest before you fix the slope. Harbour and Mondeer do not list screws as included. Do not walk the sheet. Work from a supported board or a platform.

Cutting and swarf

Cut on the ground with a nibbler or snips. Briarwood and Tata Steel’s Colorcoat guidance say not to use an abrasive disc, because hot swarf sits on the face and starts rust. Brush it off at once. Support the sheet so the corrugation does not twist. Keep gloves off any rotating tool that can catch them. A trade purlin spacing is not a spacing for this 0.25 mm pack.

When you should not do this yourself

Do not do this on a high roof, on a rotten frame, or on a covering you suspect is asbestos cement. Do not scrape, break or walk an unknown cement sheet to see what it is. A contractor takes over there, not another order of 0.25 mm panels. A long span, a house roof, or any doubt about an English Class E outbuilding is the same stop. Felt and whether you are replacing a cover are on corrugated sheets for a shed roof. If the first sheet oil-cans, or the screw spins in soft timber, fix the frame before the rest of the pack goes up.

Common questions

Do I screw the crest or the valley?
For the wavy corrugated sheet in the Cladco and Corozinc guides, the screw goes on the crest, with a sealing washer. Cladco’s box-profile sheet is fixed in the valley. These amazon packs do not state a screw position. Harbour is the listing that says classic corrugated. Mondeer, TEOV and Warmfay say corrugated and trapezoidal together, so confirm the shape in the box before you copy a valley screw onto a wave.
Can I use the screws in the Warmfay box?
The listing says 400 screws and washers are included. One review says they were too small. Try one on a crest. If the washer does not seal before the screw runs out of thread, buy roofing screws of a length that suits your timber and this thin sheet. The other packs do not list screws as included.
How do I cut the sheets?
Cut them on the ground with a nibbler or snips, which is the cold cut Briarwood and Tata Steel describe, rather than an abrasive disc. Brush the swarf off straight away so it does not sit on the face, and protect the cut edge. Support the sheet so the corrugation does not twist. A twisted edge will not sit in the lap.
Can I walk on them once they are down?
No. Treat the roof as fragile until you know it is not, which is the Health and Safety Executive line for corroded metal and fibre-cement, and a sensible line for 0.25 mm sheet you have just screwed down. Reach the fixings from a supported board or a platform. A foot through a crest is how a short DIY job becomes a fall.
What if the old roof might be asbestos?
Stop. Do not drill it, snap it, or walk it to identify it. Asbestos cement is one of the fragile coverings the Health and Safety Executive names, including on old sheds. A contractor should take that decision. A new galvanised pack does not make an unknown cement roof safe to strip.

Related pages

Corrugated iron sheets

Best corrugated roofing sheets: shed, lean-to or skip

Corrugated iron sheets: thickness, laps and screws

Corrugated sheets for a shed roof after felt fails

Corrugated vs box profile: pitch, cover and screws

Sources

Public UK sources and the amazon.co.uk listings compared on this page. Updated 22.10.2026.

  1. Planning Portal: Outbuildings (retrieved 22.10.2026)
  2. Planning Portal: Building regulations for an outbuilding (retrieved 22.10.2026)
  3. legislation.gov.uk: Class E outbuildings (retrieved 22.10.2026)
  4. Cladco: 13/3 corrugated datasheet (retrieved 22.10.2026)
  5. Cladco: Corrugated installation guide (retrieved 22.10.2026)
  6. HSE: Fragile surfaces (retrieved 22.10.2026)
  7. HSE: Using the right type of PPE (retrieved 22.10.2026)
  8. Briarwood: 13/3 declaration (retrieved 22.10.2026)
  9. Cladco: 13/3 galvanised corrugated roofing sheets (retrieved 22.10.2026)