If a Tree Grows on Your Roof, and No One is Around to See It
Does it really cause damage? Out of sight, out of mind, right? Unfortunately, no. Spouting plants on the roof and in drains and gutters is a big problem. (For the sake of clarification, we’re not talking about vegetative roofs in this blog.)
Imagine years without cleaning; your car would be covered with dust and dirt. That same accumulation occurs on your roof and if left unattended long enough, seeds deposited by the wind, squirrels, or birds can make an unwanted rooftop garden flourish. While this can occur with any type of roof, ballasted systems are especially problematic because the rock traps dirt.
If you’ve just discovered vegetation on your roof, it’s evidence of one (or both) of the following:
- Lack of maintenance.
- Poor drainage.
The Damage Trees Cause to Your Roof
Saturated leaves and blowing dust can quickly become rooftop compost, the ideal place for wind-borne seeds to grow. The conditions are ideal for algae, mildew, and mold to grow too.
What began as a dirty roof can quickly lead to larger, more expensive roof problems. Plants can’t grow without moisture. If water isn’t draining off your roof properly, there’s an opportunity for seeds to germinate. When roof drains, scuppers, and gutters are blocked by environmental debris and growing plants, they cannot divert water away and ponding water and/or leaks are likely.
The root system of plants, shrubs, and trees will quickly destroy a roof membrane and the insulation beneath.
How to Prevent Tree Growth on a Roof
That tree would never have grown if there had been routine roof maintenance. Performing the following regularly (yearly or more often, as needed) will prevent problems from taking root.
- Inspection. Perform that annual inspection that your warranty requires; you’ll be glad you did. A tiny tree that’s just sprouted is much easier to remove than a larger, older one. Inspections catch problems when they’re small, often preventing larger, more expensive repairs later.
- Cleaning. Removing dirt and debris on the roof once or twice a year will remove conditions that could otherwise be ideal for the growth of unwanted vegetation. Hire a professional to clean the roof; they know how to work safely near the roof’s edge.
- Maintenance. If there are neighboring trees, keep them trimmed to reduce the likelihood that nuts and seeds are dropped and leaves are blown onto the roof. Work with a roofing contractor to set up a schedule of maintenance activities.