This project is previously developed, though existing buildings have been demolished and basically the site is a sand area with some vegetation on it that developed after demolition. Basically the whole site will be dug out and have a basement. There will be vegetation in a courtyard and on roofs, both extensive and intensive. FAR is >1.5. Onsite soil cannot be reused as it is mixed with demolition waste.
The team is struggling with the question if the credit can be achieved at all.
1. The imported "soil" is more a substrate than soil, it is made up of recycled clay bricks with added organic compounds. We are not sure if this can be seen as "soil" at all.
2. 2items in table "Soil restoration guidelines" cannot be achieved, organic matter and compaction. both state a minimum of 12 inch / 300 mm, while the green roof substrate will be 100 and 200 mm. 300 mm can probably not be achieved for structural reasons.
Has anyone experience achieving this credit with green roofs? I have the impression this project cannot achieve the credit but the owner wants this to be rechecked.
Calie Gihl
Design EngineerLEEDuser Expert
19 thumbs up
November 26, 2017 - 6:29 pm
Hi Jens,
My first thought is that Option 2 may be an easy solution if you don't have further time or resources to dive into this issue with the soils.
Does your imported soil meet the criteria in Table 2? If so, it doesn't matter if your green roof will meet it if your imported soil accounts fo 30% of the previously developed site. If you are counting on the area of your green roof to meet the 30%, my guess is that you won't be able to comply. However, since it is due to structural reasons, you could try writing a narrative explicitly describing this exception and then submit it as a CIR.
My final idea is that you could try to submit the credit, and along with it submit a letter from the engineer of record stating the building's limitations. I am not sure if this would work but you could try!