By Andrew Cole Yanders
A diligent maintenance schedule is a principal we take very seriously. Without proper maintenance a green roof has no chance of thriving and looking its best. There is even serious threat of long term damage to the underlying roofing materials when maintenance is neglected. There is even a likelihood of an overall failure of the roof’s main purpose, to keep the building’s interior dry. Because of the grave consequences of not properly maintaining a green roof we continue to insist on a strict maintenance schedule with all our clients.
Here in the Northeast of the United States winter is upon us and we are eagerly awaiting the first blanket of pristine white snow. There are 4 key maintenance aspects we wish to highlight that are essential for the health of the roof during the winter season.
1. Clearing Drains & Gutters:
Clearing roof drains and gutters is important all year round. During the winter months moisture accumulates in large volumes on your roof and when the snow and ice melts it places a particular high level of stress on the waterproofing. If the drainage system of the roof is not operating efficiently, water will find its way through the weakest points of the waterproofing.
To maintain a properly draining roof, roof drains and gutter must be inspected and all debris removed, especially if the green roof does not have inspection boxes. Because drains without inspection boxes are much more prone to clogs, we believe inspection boxes are absolutely necessary for any green roof system.
2. Snow Removal:
Similar to any typical roof, when snow begins to accumulate heavily on a green roof make sure it is evenly spread out; snow drifts should be mitigated to avoid exceeding load limits.
In areas where snow accumulation on the roof is a hazard particular attention must be made not to damage the green roof during snow removal. So far as we know, there has been no literature on this subject and no recommendations have been made. We are recommending a 4 inches, 20 cm, buffer layer of snow. To remove any more snow allows for the potential to disturb plants and dig into the growing media.
The best method for removing snow from a green roof is to shovel the snow onto a blanket and drag it over to the edge of the roof, always remembering to leave of 4 inch layer of snow over the green roof.
The early months of the winter is a good time to check the nooks and crannies of your roof’s waterproofing. Check the caulking and look over all the access areas and make sure they are all sealed properly. Additionally, before any snow has begun to accumulate on the roof, check all areas of the green roof for wind or water erosion. Alleviating these problems areas in the winter allows for rapid vegetation covering to occurring in the spring and protects the waterproofing layer from any deterioration due to exposure to the elements.
4. Pruning & Cutting Vegetation
We are never pleased when grasses are cut in the fall or early winter. Besides providing a decorative look to an otherwise dormant field, leaving the dry seed stalks provide protection for the core of the plant and its new growth.