leanto

A lean-to, also written lean-to or leanto, is a simple structure consisting of a single pitched roof that slopes away from an existing wall or building, sharing one wall with the main construction. This arrangement provides shelter with relatively little material and labor.

Construction typically involves attaching one edge of the frame to an existing wall and supporting the opposite edge with posts or a freestanding frame. The roof is usually covered with metal panels, shingles, tile, or translucent sheeting. Common materials include timber, steel, and various roofing options such as metal, shingles, or polycarbonate. The structure is often built with a concrete or gravel floor and can be scaled from a small storage shelter to a larger extension.

Uses for lean-tos are diverse. They are widely employed as storage sheds, rain shelters, carports, or greenhouse attachments. When integrated with a house, they can provide additional, low-cost living or utility space. Sizes and roof pitches vary to suit purpose and the main building’s proportions, with headroom typically determined by the distance from the supporting wall to the outer edge of the roof.

Advantages and considerations include low cost, ease of construction, and adaptability. Limitations include limited interior space, potential drainage and water leakage issues at the join with the wall, and reliance on the attached wall for support. Local building codes or permits may apply, especially for larger carports or permanent extensions.

Historically, the lean-to is an ancient and ubiquitous building form used to extend shelter quickly and affordably. It remains common in rural architecture, gardens, and modern reproductions such as greenhouses and carports.