charlie's comments

Dear Carina and Lisa,

As I understand it the deck is being poured today. Therefore, any support system must either be designed without anchors or anchors must be drilled into the finished deck.

At the moment, I have the following pressing questions and comments:

1- The revised anchoring plan offered by the structural engineer is not, in any way, similar to our proposal. We have no objections to it, if this what the structural wants to propose. However, it is important to keep in mind that some of these anchors will ALSO have to be placed in the walls that will poured in the middle of the steep slope. This solution will require the ADDITION of a way to seal the root-barrier where the bar will penetrate through it on the downhill side of the wall. Off hand, I don’t have solution for this.

2- I will be happy to layout the anchors. The easiest thing will be to assume that there will be one anchor for every 8 sf. There will be about 300 anchors. The ONLY CAD drawing we have is A2.1.a last modified on 10-22-09. However, this drawings seems to be missing critical layers. Can you please send an Etransmit file for this, or a more recent drawing?.

3- Note that downslope from the raised beam, the anchors should be drilled into the beam. This beam should support the loads, and no additional anchors should be required downslope of the beam.

4- We are not designing the anchors. However, the final design must include a flange with a washer that will allow us to seal the root-barrier. The design could be as simple as a threaded bolt made from stainless steel or brass. The installation process would be to: 1) place a S.S. or brass washer 3” in diameter over the bolt, 2) force root-barrier membrane over the bolt, 3) a matching washer would be placed over the membrane, and 4) a S.S. or brass bold would be tightened over the upper washer. This concept design is simple to install and build. However, either the structural engineer of another engineer specializing in concrete must determine the diameter of the bold, its depth of embedment, method for securing the bolts into the concrete, and material (S.S. or brass). With this information Roofscapes, Inc. could research manufactures that offer bolts/washers that would satisfy the structural engineers requirements.

5- I have received no feedback on the drainage plan. In particular:

a. Will there be a line of roof drains following the northern wall of the ramp? Since the slab is being poured now, is the plan to go back afterward and bore holes for the drains. Are drains being cast into the slab now? If there are no drains along this alignment, this will definitely affect plans for drainage of the green roof.

b. I am confused about the pattern of flow in the small isolated triangular area south of the ramp (see area circled in pink on the attached scan). I would like to confirm that water will flow along the wall toward a scupper located at #5.

c. Do you have comments about the proposed locations of the scuppers

d. Will a large grate be added at the extreme southwest in order to receive flow concentrated flow in this area?

e. Are scuppers 4”x24” OK with everyone?

f. Once we know for sure where the grates, drains and scuppers are, we can layout the internal conduit that will collect concentrated flow and convey it to the outlets

g. Can you provide information on the design storm that is being used to size drainage facilities elsewhere on the site?

6- Where are the stub-ups for the irrigation supply? As mentioned in the past, these can be anywhere. We can run the piping below grade to where we need it. It is very important to include sleeves through the walls and curbs for the supply lines. These must be located before the walls are installed. Who is preparing this detail? Don’t forget electrical conduit.

7- With CD-time approaching, we should agree on a the details that will be generated by Roofscapes. We will need an up-to-date plan (see above) and all the sections. We can prepare dstials and specifications by 12-18. Details that we foresee as being necessary. Are:

a. Scupper (typ), including access shaft and distribution box

b. Perforated conduit layout

c. Perforated conduit detail

d. Slope stabilization assembly

e. Assembly profile for shallow soil areas, including typ. detail for capillary irrigation system.

f. Assembly profile for deep soil areas

g. Area drain detail, showing access chamber

h. Transition to decomposed granite walkway

i. Transition to wall

j. Detail at slope anchor

8- Irrigation design is not in our scope, but we can provide basic information in the specification that will guide the installation. We can also provide you with some ‘boiler-plate’ details for valve chambers that you can add to the CD set. You can ask for the irrigation layout, based on Netafim, to be prepared by the contractor and submitted for approval by Belsberg.

9- We will provide specifications for the various green roof profiles. It would make sense to include the decomposed concrete pathways in the green roof specification, since drainage underneath the paths is integrally related to the adjacent green roof areas.