A flat roof is an almost horizontal roof closure, commonly found in Switzerland on modern single-family homes, extensions, garages, carports and commercial buildings. Because water does not run off on its own as it does on a pitched roof, a continuous waterproof membrane takes over this job – together with a slight slope that channels rainwater to the drains.\n\nThe structure is built in layers: on top of the load-bearing construction (concrete or timber) come the vapour barrier, thermal insulation, a slope-forming layer and the actual waterproofing, such as bitumen sheeting or synthetic membranes. On a green roof or one used as a terrace, further protective and usable layers follow. How these layers work together determines watertightness and service life.\n\nA flat roof is needed when you plan a clear, modern architecture, a roof terrace, a green roof or a solar system – or simply for functional buildings. A specialist firm is required for new builds, renovations, leaks, or when the waterproofing becomes brittle with age.\n\nPay attention to clean connections to walls, chimneys and drains, functioning drainage and regular maintenance. Common mistakes are insufficient slope, blocked drains and poor workmanship at the connections. Ask for a detailed quote showing the layer structure and warranty; costs depend on area, structure, insulation standard and use.
Flat roof
A flat roof is a roof with very little slope (usually under 5 degrees) that closes off a building almost horizontally. Instead of tiles, a waterproof sealing membrane protects the building from rain and snow.
Example
A family in Winterthur is adding an extension with a flat roof to their single-family home and wants to use it later as a roof terrace. The specialist firm therefore plans from the outset for a stronger membrane, a proper slope towards two drains and a walkable surface. This keeps the extension watertight and makes the terrace usable from the start.
Frequently asked
How long does a flat roof last?
Service life depends heavily on material, workmanship and maintenance. A professionally installed membrane lasts many years with regular inspection. Clean connections and functioning drainage are decisive – neglected maintenance shortens durability considerably.
Does a flat roof need maintenance?
Yes. Drains and gutters should be regularly cleared of leaves and dirt, and the membrane and connections checked periodically, ideally once or twice a year. Spotting small damage early is far cheaper than dealing with water damage.
Can I green my flat roof or install solar panels?
In many cases yes, if the structure allows it and the membrane is designed for it. A green roof additionally protects the membrane, while a solar system makes use of the open area. Have a specialist check the load capacity and structure beforehand.