Ways to Prevent Green Roof Failure

A green roof or a living roof is an earth-friendly roofing alternative to traditional roofing systems. Standard roofing materials are replaced by native grasses, plants, shrubs, and trees. A waterproof membrane between the structure and the soil protects the roof deck from water and root infiltration. Especially in urban environments, living roofs are becoming popular choices for residential and commercial properties because they reduce carbon footprint, are sustainable, and are energy-efficient. If you already have a green roof, or are interested in investing in one, here are ways to prevent green roof failure.

Roof Inspections

Regular inspections are the best and most budget-friendly way to keep your green roof in good shape. Checking up on your living roof will also help prevent costly damage from occurring. Have your green roof inspected around the same time as cleaning the gutters – once in the spring and once in the fall (twice a year) to ensure that you catch problems before they become really expensive to fix. When conducting a roof inspection, look for signs of damage – broken tiles, cracked shingles, pooling water, leaks, struggling or dying plants, and plant encroachment.

Plant Encroachment

Plant encroachment is just what it sounds like – plants grow on your living roof where they shouldn’t – around drains, in the gutters, next to chimneys and vents, on walkways, and in pebbled vegetation barriers. This process can cause serious damage including blocked drains, irrigation system malfunction, root penetration, and leaks.

While it is normal for plants to spread out and grow in other places where they were not originally planted, they should be removed. They can be replanted in areas that have fewer plants or there are gaps. To guard green roof failure due to plant encroachment, conduct an inspection for wayward plants every two to three months.


Vegetation needs water to ensure that your living roof doesn’t fail. The good news is that extensive (shallow layer of soil covering a large area), intensive (thick layer of soil covering a small or specific area), and semi-intensive (a combination of both) green roofs in British Columbia can be fully functional and healthy without an irrigation system.

A well-designed living roof will include plants that are drought-resistant or native to the region and are adaptable to temperature fluctuations and climate extremes. Regardless of the type of green roof installed, green roofing professionals recommend that for the first year vegetation is watered regularly to help aid plant establishment. It is also suggested that a hose bib be included in the design for emergencies such Metro Vancouver’s heat dome in 2021 or prolonged periods of no rain.

Pest Management

You look at your living roof and see an eco-friendly house with better curb appeal. Pests see a place to call home and a source of free food. A few more mosquitoes buzzing around might not seem anything to worry about. But a pest infestation of any kind can upset plant growth, attract other stinging and nesting pests, and damage the waterproof membrane due to burrowing creatures such as rats and mice, leading to green roof failure.

If you had your roof installed by a green roofing professional, you most likely already have a pest management plan in place. If you don’t, explore preventative measures you can take to eliminate or reduce conditions that could make your living roof an attractive home for unwanted visitors. It might mean rethinking the types of plants and even the kind of mulch you use. Pests are typically attracted to plants that produce nuts, berries, and seeds. Since they also like to munch on organic mulch, switch to a cedar mulch, which can repel ants and other plant-feeding insects like aphids and mites.

Regular Maintenance

If you have a green roof you know the importance of proactive home maintenance. To provide all of the benefits of a living roof, it must thrive and be healthy. It is essentially a garden that needs regular feeding, weeding, watering, and protection from invaders. You will also need to be vigilant in spotting places on your living roof that could become vulnerable to water damage.