Good wall systems for a brick veneer?
I’m in the early stages of planning a new house, and wondering what you all would recommend for an exterior wall system that’s clad in a thin brick veneer? Here are the details:
I’m in Lancaster County, PA, so the house is in zone 5a (but surrounded to the East, West, and South by zone 4a).
We’ve got 4 small kids (6, 3, and 1 yr old twins), so we’re looking to build a house that is highly adaptable to our needs over the next decade or three. I’m trying to keep the square footage reasonable, yet still comfortable for a family of 6. Preliminary plans are just under 2,700 sf, plus an unfinished basement and attic.
The lot is located on a main road into Lancaster City, and across from James Buchanan’s Wheatland estate (among other historical landmarks), and while it’s not required by the Historical Society, I’d like to stick to a traditional architecture in a Federal/Georgian Revival style.
I’m aiming for a “Pretty Good Home” https://www.greenbuildingadvisor.com/blogs/dept/musings/martin-s-pretty-good-house-manifesto and, of course, trying to keep costs as low as possible. Seems to me that the exterior wall and roof systems play the greatest role in energy efficiency, so I want to get this right. I haven’t done enough research on the roof system yet, so I’ll stick to the walls for now. My goal is to get between R-30 to R-40 with a tight air barrier.
One other important feature is that I favor simpler, familiar methods over complex, progressive ones. After reading many of the articles here, it seems the sf price of materials is pretty close (for example: https://www.greenbuildingadvisor.com/community/forum/general-questions/21378/double-studs-vs-thick-foam-ove). Therefore the biggest impact on cost is not only how long it takes to install, but also how long the framer estimates it will take. Unfamiliar applications will always include plenty of “fluff” in the price whether necessary or not. In addition, Lancaster is a very conservative type of place where you often hear “well that’s just the way we’ve always done it.” This applies to both framers and code officials 🙂 New-fangled city thinking sometimes isn’t received well, so unusual assemblies are going to limit the number of framers even willing to bid the project. And lastly, while I have plenty of experience in remodeling, I’m no building science expert, and I’m not interested in learning the hard way!
So, ALL that to say: what wall system recommendations would you folks have for a labor-friendly Pretty Good House with a thin brick veneer? I’ll put my thoughts in the comments below to keep this post from getting any longer than it already is 🙂
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Replies
The simplest system I've come up with that meets my requirements would be, from the outside-in: thin brick - brick support panel with rain screen - Zip R-Sheathing - 2x6 wall with dense-pack cellulose - 1/2" drywall. The brick support panel would be something like this: http://www.glengery.com/thin-tech/elite-series This assembly should give me at least R-30 (if I use the R-9 Zip panel) with a continuous air barrier and reduced thermal bridge, and does so with zero additional labor cost vs. standard framing and code minimum insulation. The only extra cost is the difference between the Zip R-Sheathing and standard Zip walls or OSB + Tyvek, and the longer fasteners. Any moisture in the Zip wall should escape outward to the rain screen. Studs and cellulose should remain warm and dry. Are there any problems/risks with this setup? Additional air/water/vapor barrier(s) needed anywhere?
Other notes:
- Could easily bump it up to Zip's R-12 and/or a 2x8 wall to get closer to r-40. Good idea, or overkill for Zone 4/5?
- Other related building components such as window and door installation, drywall application, plumbing and HVAC chases, etc. should not be adversely affected nor require additional or specialized materials. This cannot be understated.
- One drawback to the Zip R-Sheathing is the ungodly number (and size) of fasteners needed. But with the brick support panel applied directly over top and having to be fastened to the studs, I expect I can kill two birds with one nail.
- Zip has a drawing for a full brick veneer: http://huberwood.com/assets/user/library/RB-2_RZS-Brick_Veneer_Wall_Section_at_SOG.pdf but if I understand correctly, this type of application will potentially lead to increased thermal bridging between the foundation and the brick. I need to check with my mason to see if thin brick on a support panel can overhang the foundation and break that thermal bridge.
- One issue may be that the weakest insulation point of the Zip system (seams) is at the weakest point of the 2x6 wall (the studs). Would there be any benefit to sandwiching a staggered layer of 1" EPS between the polyiso and the 2x6 wall, and reducing the iso by 1"? It's an extra installation step, but might be worth it.
- Is there a better or less expensive approach that's as simple as this one? Such as using standard OSB, air barrier, and iso board instead of paying for the Zip brand? Double-stud framing seems like it would be a viable alternative, but somewhat more complicated and labor-intensive for both the framer and the insulator. Or, to really throw things for a loop, I like the PERSIST/REMOTE concepts, but is there any practical way to do a masonry finish on these? Thoughts and recommendations welcome!
Typically your thin brick veneer would not terminate to a brick ledge like full brick. The most common configuration would terminate above ground with a J-bead or weep screed, although you could also run it to grade. The details would be similar to adhered stone details. The ones from huber are at http://www.huberwood.com/assets/user/library/RS-1_RZS-Adhered_Stone_at_SOG-OPT_A_(Comb).pdf
Here are two configurations meeting those parameters with a rainscreen created by Sure Cavity or Gravity Cavity. The zip sheathing would replace the 2 layers of paper/WRB and sheathing in these drawings. The full drawings are at
https://www.mtidry.com/hyperspecs/thin-brick-bottom-of-wall and
https://www.mtidry.com/hyperspecs/thin-brick-veneer-run-to-grade