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FOTD living green roof
The purpose of the project was to educate Nature Center visitors on the benefits of living green roofs, to enhance the aesthetics of the Nature Center, and to inspire others to build their own green roofs. The Dune-Gineers Green Roof was built at the Friends of the Dunes Nature Center by students at Humboldt State University Engineering 215 class.
The Friends of the Dunes is a non-profit organization, and their Coastal Nature Center is a place where they promote green solutions by educating visitors. They work to protect and preserve the natural habitats of the dunes. The Friends of the Dunes originally planned to have a living green roof put on their back terrace, so the terrace was built to be able to hold a heavy garden. They tried to get a living green roof built, but the quote given to them by the hired company was too expensive. When they were later presented with the opportunity for student engineers to build a green roof for much cheaper, they decided to give us the job.
The objective of the project is to design a green roof for the western awning at the Humboldt Coastal Nature Center, and to build a model of the green roof that educates visitors and enhances the aesthetics of the Center.
Problem Analysis and Criteria
|Aesthetics||10||The roof must look as professional as the rest of the Nature Center.|
|Local Suppliers||9||As many local businesses as possible.|
|Cost||3||Entire design must cost less than $400.|
|Weight||5||The roof must weigh less than the roof can handle. The lighter the final design, the better.|
|Safety||5||Must be designed to be accessible for maintainable and weeding.|
Describe the design and the model
Western Awning Green Roof
Using the criteria and their respective weights, we picked an option that although is slightly more expensive, looks professional and allows plants to survive in the summer. It has a low weight, and can be built without threatening the structural integrity of the building. Plastic Bend-A-Board is used for the retaining wall, with the components of the green roof layered behind. Hydrostop waterproofing paint is painted on the roof one last time to make sure the roof will not leak. The base layer of the roof is protection fabric to stop roots from growing to the roof, which is then followed by a synthetic drainage layer. The synthetic layer is a light material, and with its many pockets to hold water, it will keep the roof green during the dry months, while removing excess water during the rainy months. On top is a filter sheet used as the separation layer. Four inches of native soil is used as the growing medium and placed on top of the filter sheet. An erosion control blanket placed on top of the planting medium helps stop the soil from getting blown off or washed away during winter storms. It is made of a biodegradable material, and is only expected to last for about a year. A micro sprinkler system is installed on top to provide water during the summer. These layers of the roof stop water from forming on the roof, but create a habitat on top in which native plants can thrive.
Model of the Green Roof
Description of the Model
Describe the costs section
Western Awning Green Roof
Here are the estimated costs for the Western Awning:
|Hydrostop||1 bucket||On site||Free|
|Protection Fabric||500 ft sq||Conservation Technology||$357|
|Drainage Plates||500 ft sq||Conservation Technology||$905|
|Separation Fabric||500 ft sq||Conservation Technology||$267|
|Plastic Edge||100 ft||Ace Hardware||$70|
|Erosion Control Blanket (CS3)||500 ft sq||Western Excelsior||$180|
|Sprinkler System||500 ft sq||Home Depot||$113|
Model of the Green Roof
The costs of the materials used for building the model green roof are:
|Material||Qty||Amount ($)||Extended Amount($)|
|Plywood Board||24 sq ft||$26.88||$26.88|
|Drainage Rocks||1.5 cb ft||$19.99||$19.99|
|Soil Mix||1 cb ft||$7.99||$7.99|
|Rubber Mat||24 sq ft||$35.94||$35.94|
|Filter Fabric||24 sq ft||$6.00||$6.00|
|MGV PHL Deck||1||$6.00||$6.00|
|Plexiglass||4 by 8 in||$1.20||$1.20|
How we built the model. Have pictures.
Instructions for Implementation and Use After installation, more plants will need to be added to the roof. These can be added by carefully planting on the roof, or by spreading seeds under the erosion control blanket. Extra heavy watering will be needed initially to get the plants established.
Periodic Watering When the plants on the roof look wilted or there has not been any substantial rainfall, the roof will need to be watered. This can be done by turning on the spigot on the north side of the building, two feet of the ground. Water should occur no more than twice a week, and for only twenty minutes.
Yearly Cleaning The maintenance of the green roof will require occasional pulling of weeds, cleaning of drain gutter, and inspecting of the sprinkler heads. Quarterly flushing will require approximately one to two hours.
Safety Precautions As the blocks on the side of the roof are not attached to anything, great care should be taken when accessing the roof. A 12 foot or higher ladder is recommended.
We are looking forward to building the roof!