A) Because the plant palette is not yet finalized, the green roof profile is not yet finalized, however, the roofer only needs to install the waterproofing membrane. All other components can be considered part of the green roof profile and installed by the green roof installer. This will help to insure that the scope of the green roof is not broken up and accountability is easy to assess.
-No sheet drain needs to be provided by the roofer or membrane manufacturer (although it may be part of the green roof system depending on the ultimate build up.)
NEED CLARIFICATION-Roofscapes, Inc. is unclear if insulation is required in the build-up. We have discussed using insulation to meet elevation requirements but we are unclear as to whether it is otherwise required in the roofing build-up. Please clarify.
B) Roofscapes, Inc. provides a warranty for our green roofs, however this warranty is only offered if the green roof (all components above the waterproofing membrane) is installed by a trained and licensed Roofscapes, Inc, Network Contractor (much in the same way that roofers are certified to install particular membranes). Roofscapes, Inc. will be on site to supervise the installation as part of our Quality Assurance Program (see attached). If there is a contractor that is not in our Network, we would be happy to discuss the option of them joining our Network.
C) 3 membranes are being considered, EPro, Sarnafil, and American Hydrotech.
-The EPro and American Hydrotech products require an extra root barrier to be installed over the membrane. Please make it clear if the roofers intend to install this layer, what exactly the product is and how it will be installed. Roofscapes, Inc. recommends a minimum 30 mil polyethylene, polypropylene, or PVC, heat welded at the seams.
-The root barrier could be installed by either the green roof contractor or the roofer.
-EPro and American Hydrotech should confirm that they will honor their waterproofing warranties with the designed green roof on top of their membrane. Sarnafil and Roofcapes, Inc. have a national agreement to provide a comprehensive warranty covering the entire system including all components above the waterproofing.
D) EFVM testing is a leak detection method.
-The test can be used as a quality assurance measure (preceding green roof installation) to insure that the waterproofing is water tight and it can also be used to locate a leak if one occurs in the future.
-In order to use the test for quality assurance, nothing needs to be installed under any of the membranes as long as the membrane is in contact with the roof deck. If Sarnafil chooses to install their system over other components then a grounding screen should be installed directly below the membrane in order to use EFVM for quality control.
-When the test is conducted the technician will place a wire around the perimeter of the roof areas. Laying this wire is part of the cost of the test and does not need to be included in any contractor's scope.
-The root barriers that will be installed with the EPro and American Hydrotech systems could potentially interfere with the use of EFVM should it need to be used to locate a leak in the future.
E) The concrete walls WILL NOT be poured on top of a sheet drain, which means that rectangular scuppers will need to be installed in the walls in order to facilitate proper drainage between the different green roof areas.
NEED CLARIFICATION-Roofscapes, Inc. has not seen a roof plan that shows where the roof drains are actually placed on the roof. Please send us a plan or photos that show where these drains are actually located so that we can create a plan for where the scuppers need to be placed and how large they need to be.
F) Lisa and Karla are getting closer to finalizing the plant list. Once the plant list is understood we need to clarify exactly what the water burden will be for the irrigation system.
Please let me know if you have any questions.
Regards,
Nate Johnson
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