A green roof is a layered system: structure, waterproofing, root barrier, drainage, growing medium, and plants. Get the layers right and a living roof slows stormwater, cools the building, extends the life of the membrane beneath it, and turns an empty roof into usable space. Get them wrong and it becomes an expensive way to grow weeds.
Extensive green roofs are shallow, usually three to six inches of lightweight growing medium, planted with sedums, hardy succulents, and tough native grasses and perennials. They're light, low-maintenance, and the right choice for most residential and commercial roofs. Intensive green roofs are deeper, support shrubs, small trees, and real gardens, and require more structure and more care. Rooftop gardens and amenity decks are usually intensive.
Colorado adds three challenges: intense high-altitude sun, drying wind, and repeated freeze-thaw cycles. The answers are plant selection (species that shrug off all three), growing medium depth that buffers roots from temperature swings, and an irrigation strategy for establishment and for the driest stretches of summer. Drip on a roof is not optional here; it's how the plants survive the first two years.
Denver's Green Building Ordinance has made green roofs a familiar option for larger commercial and multifamily buildings, but they work on homes too: garages, additions, and flat-roofed modern houses are ideal candidates.
A green roof project involves your architect, a structural engineer, a roofer, and a landscape designer. We coordinate with all three so the roof you get performs the way the drawings promised.