Which exterior sheathing method would be better?
Going to be building a 2,000 sq ft home in Georgia, zone 2, slab on grade. Home is a farm house style single level with full wrap around porch with concrete log siding. For exterior sheathing should I do Zip-R panels using the 2.0 method with Roxul exterior insulation then rain screen then siding or Advantech sheathing with Delta Vent SA, Roxul exterior insulation, Delta Dry then siding with Roxul batts on interior?
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Can you tell us specifically what siding product you are using? Maybe post a link. I'm not familiar with concrete log siding and would be interested to know what the installation details are before considering your assembly options.
Here you go!
Here is the Installation guidelines.
I'm hoping that some members will jump in with thoughts on your assembly options as I don't know much about detailing exterior mineral wool. However, the siding installation guidelines call for pan head screws fastened into studs. Have you verified that it is okay to fasten the siding to furring strips?
What I verified was that due to the weight, they want the siding screwed thru exterior sheathing into studs. Going to have to contact them again, because there has to be a way with current building methods and codes changing to use this product with exterior insulation. I'm wondering if I would have to do horizontal and vertical strips to ensure proper strength. I'll see what they say and report back.
Newvision, why do you want both Zip-R sheathing and exterior mineral wool? Both products can work well but it would be unusual to combine them both on the same wall.
On your other option, why do you want a self-adhered WRB over Advantech sheathing? Delta's product is good, but expensive; you could save money with a WRB that is not self-adhered. You can tape the seams of Advantech to make an airtight layer.
As for hanging siding on furring screwed through exterior insulation, there is a technique where you install screws at various angles to create a rigid truss. This product (and supplier) offer custom engineering for this approach: http://www.smallplanetsupply.us/heco-topix-therm-insulation-screw-4-7-to-17-75-inches/. (At least they used to.)
Thank you for the screw recommendation, I really appreciate it! Reason I was looking at Zip-R with Roxul exterior is I've researched and found construction with the flash and batt technique with Zip-R and Roxul in the stud bays. My thinking is that with the Roxul on the exterior, Zip-R with 2.0 method gives me better envelope and no need to put insulation in stud bays. This will work better at keeping the outside out and the inside in since the log siding is concrete and concrete holds more moisture and Savannah is very humid and gets hella rain when it rains.
You wrote, "I've researched and found construction with the flash and batt technique with Zip-R and Roxul in the stud bays."
OK. That's possible, I guess -- but I wouldn't do it that way.
You wrote, "Zip-R with 2.0 method gives me better envelope."
Can you please explain what "2.0 method" means? I'm not familiar with the phrase.
You wrote, "No need to put insulation in stud bays."
If there is no need to put insulation in your stud bays, why are you thinking about the flash-and-batt approach? Flash-and-batt is a method of insulating in your stud bays.
I'm sorry I mis-spoke. I was trying to show an example where people have built a few different ways with normal exterior sheathing, exterior insulation and stud bay Insulation method. Plain Zip sheathing, exterior insulation and stud bay insulation. Zip-R sheathing with extra exterior insulation and no interior Insulation or Just Zip-R with Roxul batt in the stud bays. The Zip-R 2.0 method is where ever hole and seam is sealed with liquid flashing instead of tape.
I am thinking that the Zip-R sheathing sealed with the 2.0 method with Roxul comfortboard on the outside of that will give me the best performance. Am I thinking correctly or am I totally wrong?
Q. "I am thinking that the Zip-R sheathing sealed with the 2.0 method with Roxul Comfortboard on the outside of that will give me the best performance. Am I thinking correctly or am I totally wrong?"
A. I'm not sure how you measure "performance" -- probably in terms of airtightness and R-value. Suffice it to say that you can achieve almost any airtightness target, and almost any R-value you want, with a wide variety of approaches: studs plus continuous exterior insulation, PERSIST, double-stud wall, etc. So your suggested method (a) isn't better from a performance standard from many less expensive alternatives, and (b) would be more awkward to build than many less expensive alternatives.
I find it interesting that if you read Huber's instructions, sealing joints between panels isn't a recommended application for their liquid flashing.