Best way to attach brick veneer to 12 inches of exterior foam?
I am planning a 15 x 15 foot interior dimension addition with slab on grade foundation, ICF walls , 12 inches of exterior XPS rigid foam and exterior brick veneer. I plan to tape and seal the rigid foam to the ICF but am not sure of the best way to attach the brick veneer.
If I use a brick tie attached to the ICF, I would require a long brick tie that traverses the 12 inches of XPS foam, which I think would be difficult. Another option would be to apply OSB or plywood sheathing exterior to the rigid foam and attach the brick to the OSB/lpywood. Exactly how I would attach the OSB/plywood to the foam is also not clear to me.
Any thoughts on the best way to attach brick veneer to 12 inches of rigid exterior foam?
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Here is an alternative that may be of interest. As per the manufacturer, it is an insulated (R-10) real brick veneer panel. http://www.panbrick.com/
Brick ties to furring strips on the exterior of the foam. Attached to the studs.
+1 to Jeffrey Melvin's idea.
Why 12 inches of exterior XPS?
What climate zone are you in?
Is the rest of the house insulated to this extreme level?
How well airsealed is the rest of the house?
I won't claim to understand what you're describing based on the information provided but if you're convinced your plan is good you might want to consult an engineer.
Lucas
I am in zone 5 and I agree that 12 inch of exterior foam is excessive but the original plan was to create a contained space that essentially met Passive House standards. A more realistic approach would be to decrease to 6 inches (still significant with 11inch ICF). Even at 6 inches of foam tying to the ICF could be a bit difficult. The house is about 5,000 square feet of living space but I find that at this point in our lives we essentially spend 95% of awake time in the combined eating / kitchen area. I want to connect the addition to this area and maximally thermally insulate with the concept of spending most time there and significantly underheating the remainder of the house. The addition will open into the house by sliding double pane patio doors (placed interiorly). I am trying to avoid plywood/OSB sheathing just to support brick veneer and probably Jeffrey's suggestion of furring strips would work although I am not certain that furring strip attachment to stud edge above and foundation base below would be stiff enough.
http://www.simpsonanchors.com/catalog/mechanical/heli-tie/index.html
Might have to use a smaller layer of ext. foam to make these work.
Tim, if the overall goal is to lower the energy usage in your already large home this addition seems a very odd strategy. I hope you've already done what you can to tighten and insulate the rest of the 5,000 s.f. Your wall section is pretty odd too. One way or another the veneer is probably best managed with furring strips, but in the absence of any framing to tie to I'd be concerned how you're going to manage your window openings. You need to think this through very carefully.
James, the securing of the windows should not be a problem. They will be secured to the wood bucks that will be built into the ICF. The 6 inches of rigid foam will be on the exterior of the ICF. I don't think that this is a particularly unusual wall construction for a green construct. I am trying to determine the best way to support the exterior brick veneer and would rather not have to use extended brick ties into the web of the ICF as it will be difficult to localize them once the 6 inches of foam is applied. This leaves me either having to apply an exterior OSB sheath, which I would then have to vapor barrier, or alternatively simply using furring strips which may be difficult to support to the rigid foam or at the top and bottom edges of the ICF.
I agree that my strategy is different but I believe practical for my objectives. I have a large home that we dont want to leave although we do not use 90% of the home. This addition will open into the area of the house that we do use. I intend to run an existing heat pump for the small area that we do use and have a separate zone with hydroponic radiant floor heat in the new addition that we will be primarily using. The addition will be "contained" with sliding glass patio doors that will enter into the exterior wall of the existing space that we use. This space currently has exterior french doors which will become the interior glass "patio door". By isolating this addition, and locally heating the small existing area that we currently use I should be able to run the thermostat much lower for the 90% of the house that we are not routinely using.
Tim,
Did a little more digging and found this FEMA doc: http://www.fema.gov/pdf/rebuild/mat/brick_veneer.pdf
That led me here: http://blog.heimsath.com/blog-0/bid/45533/Residential-Construction-The-Ties-that-Bind
Obviously, consult an engineer but using commercial ties may be your answer.
Jeffrey, thank you very much as the links are very informative. I will follow up and see what is available for 6 inches of exterior foam. I cannot imagine how the web connections in the ICF can be found once the rigid foam is applied externally. On the other hand connecting the ties to the ICF web before the rigid foam is applied must make it difficult to place the foam with 6 inch rods jutting out from the ICF
I do not have much experience with ICFs, however, I definitely think you need to run this by the manufacturer of the ICF product you are using to make sure they have accounted for this loading (there is even a chance they have seen this install before and have a standard detail--though maybe not with as much insulation). That being said, I have seen ties for ICFs that are placed before the walls are poured (though i have never used them). Yes, you would then have to piece the added insulation around the ties, which will be a pain, but I would think it would be worth it to make sure the ties actually have a proper connection--they are going to be long. You also want to make sure that the ties have some vertical adjustment so the wire part can be placed in the joints and not create eccentric loading.
Finally, you need to be very careful with your edges and joints. Each of these layers of foam insulation has the potential to be a vapor barrier, we try not to have multiple vapor barriers in any system because if moisture gets in between them, there is no way to get out.
I have been in contact with two major ICF manufacturers and two major brick tie manufactures and none has had any experience with tieing ICFs to brick venner through such a thick layer of foam (12 inches). I have not been able to tfind a tie that is long enough, mobile enough, and able to be attached to the webs of the ICF. I suspect that the outer layer on structures that have such thick exterior foam sheathing over ICF has always been a stucco type finish thereby obviating the need for ties. I am beginning to think that the only way to have ICF and thick exterior foam is to attach the brick to wood framing exterior to the exterior foam.
Tim,
Both of these features make walls thicker without adding thermal value: brick veneer and ICF. Combining them makes a pretty thick wall automatically, but then you're talking about making this a high-R assembly. My reaction is: forget ICF and make this a double frame. It could reduce thickness by 6" (the concrete core) or just choose your target R-value and space the frames accordingly. Then the outer frame can back up the brick veneer with a normal type of tie.