• Single sheet from wall to eaves
  • Flashings and trims to suit
  • Guidance on minimum pitch
  • Choice of 16 colours
  • Nationwide delivery within 7 days

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Lean-To and Mono-Pitch Roofs

A lean-to is a mono-pitch roof running from a wall down to an eaves, and it brings two problems an ordinary pitched roof does not. It is usually shallower than the builder would like, because head height at the wall is limited, and it meets an existing structure along its top edge.

Both of those are about water. A shallow roof moves water slowly and gives it time to sit; a junction with a wall gives it somewhere to get in.

Pitch

Steel sheets rely on a fall to shed water, and at the horizontal laps a shallow pitch lets water creep back up between the sheets by capillary action. The shallower the roof, the more the laps have to do.

Where we can cut the sheets to run the whole slope in one piece, there are no horizontal laps at all, which removes the problem entirely. On a lean-to that is usually achievable.

The abutment

Where the roof meets the house or barn wall, a wall flashing carries water out of the junction and onto the sheets. Done properly it is tucked into a chase or under existing cladding rather than simply sealed to the face of the brickwork.

We supply flashings and trims made to suit the profile and the junction.

Single slope roof profile
Flashings and trims

Specification

Box profile is the usual choice for a lean-to. Its stiffness along the length lets it span from the wall plate to the eaves with fewer intermediate purlins, and that matters on a structure that is often built off a light timber frame.

If the lean-to encloses a workshop or store rather than an open log store, treat it like a closed building and consider anti-condensation sheets. If it is open-sided, standard sheets are normally fine.

Where the lean-to covers a window or a door, a GRP roof light in the run keeps the daylight the original opening was there to provide.

All of our sheets are made to order at our Bromsgrove facility and cut to your exact lengths, so there is no cutting on site. Choose from plastisol, polyester paint or plain galvanised finishes in 16 colours, with nationwide delivery within 7 days and a 48-hour express option on request, subject to availability.

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What Coatings Do We Offer?

We always recommend our PVC Plastisol-coated sheets due to their cost-effectiveness and excellent resistance to abrasion and corrosion. Polyester-coated sheets are also a high-quality, versatile option suitable for both box profile and corrugated roofing sheets. However, care must be taken to avoid scratching during handling and installation.

Give us the wall height and the projection and we will work out the sheets.