Some things I leave to others and waterproofing a foundation is one of them. So, from observation only, here is what our foundation guy does. A black goop is troweled onto the foundation wall. This stuff is way too thick to roll on, never dries out completely and appears to have something like bits of fiberglass in it, it looks a bit "hairy". I've never looked to see what it is, brand name and all, sorry, but it must be the modified stuff others refer to. Over this his guys lay on a mesh fabric, looks like real fine screen material but is lighter. This is troweled onto the wall, not unlike how you squeegee a tile membrane onto thinset. Now a second layer of the black stuff covers the mesh. Lastly they cover all this with a dimpled, plastic drainage board that is nailed right into the wall. The "nails" have a collar or gusset on them and are hammered into a drilled hole. Now he uses drain rock contained within geotextile to surround the perimeter drain and come up over footing and to the bottom of the drain board. Once the perimeter drain is rocked the geotextile is flapped over top and back filling proceeds. Depending on the site and sometimes just a certain wall he often back fills with drain rock (using a thumper to compact) quite a ways up and the entire perimeter is done by hand, not machine, until he is well off of the perimeter drainage system. Even when he uses his machine he is very careful. We often pick up the "last lot" in an area, the lot that no one else wanted to build on and lots of rain and groundwater are givens around here. We warranty our homes and the last thing you want is to be digging up landscaping and such to hunt down a leak and this guy has never once failed us. No water, no dampness, no call backs. Worth it to me.

Dow doesn't make ThermaWrap R5.0, DuPont makes it under the trademark Tyvek. It is not foam board but 1 1/2 inches of soft polyester insulation with Tyvek HomeWrap adhered to the front of it. It requires adding 1 1/2" thick furring vertically and around all openings. Even DuPont admits it costs 15% more than expanded polystyrene foam board so the use of Thermawrap R5.0 seems like a bad idea like so many of DuPont's ideas. It's a chemical company pretending to know how to build buildings. Be skeptical of any material recommended by its manufacturer and look beyond the internet for building design information.

Springtime - Thank you for the input. We ended up using a rain screen behind the fiber cement siding. We framed with 2x6 exterior walls so we felt with the blown in cellulose insulation we didn't need the 1" sheeting. 2” is better than 1” which is better than ½” which is better than plain OSB. You can keep increasing the amount of insulation, but at some point the ROI just isn’t there. JDS – The nail guns used to nail into studs (not at the seams) sunk too far into the zip panels. It seems really hard to not have this happen. This punctures the WRB part of the zip system. You could tape each stud, but that seems much more labor intensive then just wrapping up the house a second time. I really like the idea of the zip system, but after going through the installation I question the WRB aspect of it. The taping has to be perfect and I mean no wrinkles, no tears, no water, dust, dirt, mud, sawdust underneath the tape, etc. Probably hand nailed because the nail needs to sit flush and not sink in at all. No nail gun can be adjusted enough to account for the differences in stud hardiness. Seemed simple enough to run some standard house wrap around and not have any concerns or a simple rain shield in our case.

Let's leave the architect thing out ok? I don't have an architect and even if I did, second guessing him/her would be perfectly reasonable. Now - Pacific NW is wickedly different than the rest of the country. And it has great variability. But you said coastal which limits things a lot. First - you don't get cold. You get cool. And then it rains.... a lot I am told. Your original post mentioned ZipR which has R value. Most zip historically has not been R. So you need to differentiate there. The R means little in your climate especially when you mention your walls. "R23 Bibb" - That sounds thick and reasonable but I still don't understand it. Material? Wall thickness? For me - Bibb typically means cellulose and 2x6 is about R20. So I am hear guessing do you have 2x7? Now - onto the Zip question vs Plywood. They have different strengths - literally. Zip is a vapor barrier with sheathing. Plywood is just sheathing. Zip will be more air tight. This now becomes a "what I am used to doing" and local custom. Zip is the modern approach and many in the industry are conservative - sometimes for good reason. Stick with tried and true. Horribly climate/rain dependent. I was building at NC coast. So different but water is important. I wanted to do Zip but the cost was too much for me. So I have plywood in parts, OSB in most and Tyvex. Neighbor spec house did felt paper on OSB (and probably some plywood). No rain screen but vinyl siding. Neighbor has hardi with no rain screen. Now I am building inland and doing Zip (possibly R) because cost is less of a concern. My other issue at the beach is that it is unoccupied in the winter so R and air sealing less important. There is no one correct way and the priority in your area is mold and siding longevity I suspect. Air tightness and R are less of a consideration (but still important).