Green Roofs in Wiltshire

The first question with a green roof isn’t the planting — it’s whether the deck below can carry the weight. Before we quote anything, we check the existing structure: joist sizes, spans, condition. A garage or a flat-roof extension might take it easily, or might need reinforcing first. We find that out before we start, not after.

Once that’s confirmed, the build-up is straightforward but has to go together in the right order: waterproofing membrane, a root barrier so nothing grows through it, a drainage and reservoir layer to manage rainfall, a filter fleece to stop the substrate washing into the drainage layer, then a lightweight growing substrate — not garden soil — topped with sedum matting or, on some jobs, a wildflower mix.

What you get: a habitat for insects and birds, rainwater held back rather than sent straight to the drain, extra insulation and sound deadening, and — the reason most people actually ask for one — a roof that looks considerably better than a stretch of black felt when you’re looking down on it from an upstairs window.

Maintenance is light but not nothing: an annual check, weeding out anything that shouldn’t be there, and keeping the outlets clear so water isn’t pooling. Most domestic jobs use an extensive sedum system, which is what we’re describing here. Deeper intensive green roofs — the kind that support shrubs or a roof garden — are a different proposition and need real structural capacity most existing roofs don’t have.