by • May 22, 2014 • Building Science, Housewrap & Waterproofing, Insulation & Air SealingComments (15)9754

Perfect Wall – Intro Video

I’ve done several posts about “The Perfect Wall” recently to my blog, but I thought I needed to step back and actually explain the concept in one concise video!  Hopefully this will get you thinking about this concept….

I first heard this presented about 5 years ago, and it’s taken me a while to mentally process the science and agree with the concept.  My project is really going well.  I’ll be doing more posts soon on this topic as the siding crew is installing the Rainscreen Metal siding & roofing this week.

Metal Siding on Perfect Wall House - Risinger Homes

Metal Siding on Perfect Wall House – Risinger Homes


Matt Risinger
– Risinger Homes in Austin, TX

Risinger Homes is a custom builder and whole house remodeling contractor that specializes in Architect driven and fine craftsmanship work. We utilize an in-house carpentry staff and the latest building science research to build dramatically more efficient, healthy and durable homes.
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  • William Gross

    Are you concerned about the rigid foam boards being damaged? Spending much time in Tornado country and now in the wintery northeast I am concerned that those multiple layers of insulation could easily be compressed. From experience I know that some siding mat’l will give extra strength (wood/cementitious clapboards) but you wouldn’t want to use say a veneer stone.

  • Peter L

    Why use wooden furring strips? It seems contrary to the low-maintenance, long-life philosophy. There are various non-degradable products out there that could perhaps have a much longer lifespan.

    The only benefit to the wooden furring strips that I can think of is that they provide structural support for the metal siding. Although the foam is “rigid”, it is not substantial enough to support the siding. If the trades could be persuaded to do things properly, they could fasten solely into the furring strips and minimize protrusions through the foam into the main wall. Was that the reasoning?


    • Peter, The wood furring strips are critical to attach the siding. The wood strips attach with long screws to the framing, then the siding is attached just to the fur strips. Are you concerned the wood might degrade? They will be hidden from UV damage by the metal siding, and if they got when the air gap would allow them to dry. I expect them to last longer than the metal siding. Matt

      • Peter L

        The assembly that you describe makes me think of a Larsen truss. The difference here is that the rigid foam and fasteners form the “web” of the truss. Yes, I was thinking moisture.

  • Jim Van Overschelde

    I have two questions. When you have a porch roof or other heavy load attachment, how are you dealing with the thermal bridging – insulate on the inside in those areas?
    And, have you tried attaching stone, as is common in the Austin and hill country areas, and how do you deal with securing them to the wall?

    • Jim, We used metal “tabs” that were lag bolted to framing, then flashed around them and insulated over them so only a tab was sticking through the foam. We then welded a channel to the tab that holds the awning structure. It minimized the bridging but we still have some slight bridging.
      I’ve not attached stone to this thick of foam, but you could install stone to a foundation lug and use this same wood furring to attach your masonry ties. OR, you can buy commercial ties that have a long screw through the foam to framing. I’ve used that method and it’s a tricky detail. I would install masonry right to the 1×4 lath. Only detail I’d change would be to use a mortar net at the bottom. Best, Matt

  • bruce john

    Tell us about the window detailing you are using with this system. It looks like a persist style wall, too?

    • Bruce John, If you’re familiar with PERSIST you are a well studied Building Science Geek like me! This is a very similar method. The windows were installed with Carlisle Elastoform for sill pans, then nail flanges were covered with CCW705. I used an expanding foam tape on the inside of the windows for air tightness. I need to do a video on that new product. Best, Matt

      • bruce john

        Thanks for the info, I’ll look forward to the video. I am not near the building science geek you are, yet. What about the window bucks? How did you form your exterior return extensions for the innies?

        • We set the windows at the shear wall to make waterproofing with a standard window flange easy. Then we used “L” metal bucks to form a buck around the outside of the window and have a place to terminate the foam. With the metal siding this was easy and looks great. Matt

  • Patty

    Matt – How would you compare the Carlisle product to the Grace product normally used in PERSIST applications? Was the Carlisle cheaper, better? Also, did you consider the Tyvek product used by the REMOTE folks in Alaska for the walls as a less effective, but less expensive option? Were you at all concerned that the wrap would outgas to the inside of the house? What would you have done differently with this house after your experience? Did you consider using the Roxul comfortboard instead of foam board for this project since it is more bug and fire resistant? Thanks. And keep those videos of perfect wall construction coming! Thanks for educating the rest of us. Patty (I’m designing a perfect wall/roof/foundation house in Virginia.)

    • Patty, I’ve generally heard good things about the Grace products, but Carlisle is well distributed here in TX and I’ve used their products for years with good success. I also find them pretty competitive on price compared to Grace. I didn’t consider a Tyvek product as I wanted at 100% water/vapor/air barrier on this project. I was really only looking at 40mil peel & stick products which I think are pretty hearty for this application. Remember that I don’t have ANY interior insulation so the membrane will remain at “room temperature” through it’s life. I did have some concerns about outgassing and that’s a big reason we added the OSB shear wall on top of our 1×6 boards on the inside. I’m not using sheetrock on this house either. I looked at Roxul and I think it’s a good product but for the price I didn’t have it in my budget. I would have also needed more thickness with Roxul because of a lower R per inch. The metal exterior skin makes this house pretty fire resistant, but I’m on a city lot so that’s not really a big concern in the long run. More videos and blogs to come on this house. I’m about 3 weeks from client move-in so I’ll be posting a completion video to show the final product. Best to you in your project! Matt

  • Connie Tinkham

    I assume the house was built slab on grade. I’d imagine the slab wasn’t insulated underneath
    due to termites prevelant in Texas. Are you concerned with “cold concrete” possibly being source for condensation? Is it even a concern in TX climate?

    In my old house (concrete slab on grade/ 2×4 construction cavity spray foam’d) I had a desk along exterior wall, the perimeter of the floor was noticably cold…near uncomfortable cold. Would this be a condensation point? If wood floors laid on the concrete would you worry about condensation (then mold) under the wood floor?

    I’m thinking of building using the same concept but am racking my brain trying to figure out how to address the issue. Was thinking of running compression strength rigid foam then osb sub-floor then hardwood.


  • Michael Anderson

    What type of flooring/subfloor did you use on the “perfect wall” house, and how was it fastened? Using the structural subfloor as the finished floor is a great idea. Thanks for building education efforts.

  • John

    First off I’m building my first house and Im running same 7/8” corrugated siding but in vertical direction. Thinking of using 1” deep vented metal hat channel screwing it thru the 2” rmax polyiso adding siga nail sealing tape at those points into my 2×6 @16o.c. wood studs w/ 3/4” plywood sheathed walls. Trying to avoid hurricane wind lifting panels here in New Orleans and minimize penetrations into the polyiso. Will be using the rmax and siga wigluv tape to make a clean WRB. I did glue all the sheathing to studs and left 1/8” gaps then sealed the gaps with Ecobond HD a zero voc construction adhesive. Also coated the plywood 2-3 times with Kool seal elastomeric roof coating low voc as temporary WRB mainly because Its a one man build, you can’t roll on tar paper or tyvek house wrap by yourself on 20′ tall walls. Plus I feel nailing warps into sheathing is just making to many holes for leaks. Check it out my build in the lower 9th ward