Vegetation on the Roof: Roots Can be a Problem

Green Roofs

There are so many great things about a green roof, or having vegetation on the roof. They save money in numerous ways. Insulating the building, preventing water damage, preventing UV damage and providing food. They’re becoming more popular and are an excellent investment. Did you know the Olympic Village has many green roofs on its buildings?
Olympic Village Green Roof: Vegetation on the Roof

Vegetation on the Roof

If you’re getting one installed, you’ll need to know that the very thing that makes it a green roof, the vegetation on the roof, can also cause damage.  Plants start from seeds and seeds get spread around from gardens.  The wind, the bees, the butterflies and birds all help spread the seeds around.  Some end up on the roof membrane and the start growing roots.  It’s so important to have a quality roof membrane so they can’t get in.

This isn’t  just a problem for green roofs.  This can happen to any roof!  We’ve seen roofs that could actually be mistaken for green roofs.

A picture of weeds growing on a roof.

Sometimes it’s a few grassy weeds.


A picture of weeds growing out of the roof.

They grow tall.


A picture of a man standing next to a small tree that is growing on the roof.

Like a shrub.


A picture of vegetation growing on the roof.

Like a bush.

a picture of a small tree growing on the roof.

Like a tree.

They grow even if they weren’t meant to.  It’s a bad sign when vegetation on the roof shows up with its roots in the membrane.  Those roots are trying to find water in any way they can and will draw it down into the membrane.

Prevent Possible Root Damage from Vegetation on the Roof

Uncontrolled vegetation growth on the roof poses serious problems. For example, blackberry bushes have strong root systems which quickly and easily cause damage to the membrane.

Dried grasses and moss pose another safety concern especially in the hot summer months. A simple spark can ignite the dried grass and moss creating a serious risk of fire. Making sure such vegetation is regularly cleared off your roof is essential to proper roof function and safety. Such proactive measures will help extend the life of your roof system.