My wife and I are building a 2-story house with 2x6 walls, we have a solar slab in the south portion of the first floor and the rest of the house has a crawlspace.  The siding will be EIFS.  So the question is, do I care a lot about caulking under the nail plate, or the rim joist between the first and second floor.  I am trying to build an extremely tight house and then add an HRV for air exchange.  I am thinking my wood stove will have outside make-up air and my forced air heater will be in the attic.  My builder rolls his eyes at me when I tell him I want gaskets everywhere because he says the whole house is already planned to be wrapped in two condoms.  He did suggest raised heal trusses and foam to get the attic sealed. 

The house is in Lake Tahoe, so 1 month of near-zero weather and then mostly pretty mild, lows in the teens and 20's and highs rarely above 80. We get hurricane force winds 10-20 times a year.

Thanks

Why would you put so much effort and money in a wood house? EIFS on a wood house? Hurricane force winds, and wood? We have people die in wood houses most years, here in Minnesota, during tornadoes. Two last Thursday.

So here is the deal here. ICFs are 10% more expensive that 2x6 and sips are 20% more expensive than 2x6 construction. ICFs do not offer an advantage over properly constructed 2x6 construction here. We do not have a cooling climate at all. Every night the temp drops into the 50s and it is nice with the windows open, or it is cold. I live in a very poorly built house now and my heating bill is $35 per month because I use wood. I am a forester, all of my wood shows up cut and split by an wood processor for free. So there is never a payback for me. I did consider ICFs but they are not thermal mass. So the logical construction was concrete with foam board on the outside, but that was too expensive. So with the extra cost in mind and my budget I went with a properly designed and engineered wood house. My house is engineered for a 250lb snow load with 100MPH wind during a magnitude 6 earth quake. We have never had a tornado which is 200+MPH winds. So that wasnt the concern at all. One huge concern was that the contractors up here do not use ICF often and the ones that do are really expensive. I am building an 1800 square foot house. They wanted $400,000 for ICF. I didnt have it.

Here is the kill shot, my boards will travel less than 100 miles from log landing to mill to my house. People talk green, but how far is concrete traveling to get into ICF houses? How much energy went into the concrete? How much CO2? So my house is a carbon sink, no ICF house can say that. Now all of that is my special scenario. Most people do not have unlimited free firewood. Most people cant get the mill to run their house package. So I have a way different set up than most. But it does make wood a better choice for my project.

10% more is too much more, here in MN ICFs add less than 5%. The superior strength and mold resistance would benefit you. ICFs are ideal for EIFS type coatings and EIFS will cost cost more over wood.

By all means over-do-it with your house. Contractors often complain about doing any more than the minimum and you will likely have to be there to make sure they do things the way you want. An actual air-tight vapor barrier is a difficult thing to do. EIFS is weather resistant but you may wish to use the waterproof base-coat that most manufacturers offer, especially over wood framing.

Brad it really varies, I live less than 30 miles from millions of acres of structural grade Douglas fir and 40 miles from the mill. Also we have to truck concrete heavy up the hill and light back down, so it is 2000 verticle of climbing over 30 miles to get concrete into the Basin. Concrete is $160 a yard. My guy is really relying on the EIFS specific Tyvek and then has a crew that will caulk and foam the house to get the seal I want. But then I am reading about sealing the sill plates and rim joists, but my builder is saying the Tyvek covers that. He is more concerned about windows, lights and other penetrations than rim joists and such. Is he right?

WRB's are called air barriers but really they aren't much of one in real world conditions. So your tyvek drapes over the sill and then what? No one seals the tyvek to the top of the foundation and for the amount of water i've come across behind wrb's including tyvek, woven brands, even so called premium wrap such as Dows Weathermate (horrendous product), you wouldn't want to trap the escape of any penetrating water anyways.
I am in the camp of relying on wrb's as a houses raincoat. Air sealing is another matter entirely, so if your builder doesn't think you'll get air leagage because you've draped a piece of tyvek over the mudsill you should be worried.

And by air sealing I dont mean laying a 1/8" bead between the rim and mudsill or the mudsill and foundation or anywhere else because it wont last. You either need to do it inside so you lay enough material or put a v-bit router bit on and bore a channel to recieve an appropriate amount of sealant. Home auditors I've talked to say the mudsill location overall is one of the leakier areas of a home, and i've stuck a thin piece of metal under the mudsill with the cheap foam gasket to the outside to demonstrate this fact to homeowners.

As far as water penetration, with EIFS, nailer flange windows are the most prone for leakage. A caulk-able gap, according to the manufactures instructions, should be left for expansion and contraction, between the windows and EIFS.

But the rim joist of wood framing is more of a problem for air infiltration, pests and difficult to insulate well.

So pay attention to both and all areas. Make sure the plasterer is "checked out" in the brand of EIFS that is used and review the manufacturer's detailed drawings yourself.

Perhaps your builder will agree to an ACH50 value - then let him worry about how to best get there.

I built a house in 98 that was to be the house to die in etc etc anyway wet spray cellulose, plywood sheathing, tyvek all taped up, good windows, radiant heat, top down ac w sealed ductwork, the only air leak I could feel was in the rim joist box sill area as the air comes in the bottom of tyvek and looks for any way in. I support your choice in stick frame...Eric

Ilgeo,
You did all that and still can "feel" air infiltration, just think of all the air infiltration you can't feel.

It was right under my desk in an area hidden by a porch roof....it was pretty efficient 3800sq ft app 65000 btu heat loss in Chicago area with a lot of that to dh windows and 2 masonry conventional fireplaces. I will eliminate box sills where ever possible in the house I am building this year and use mastic or good gasketing material on stack joints. I like both icf and sips but in this area they are not competitive. I am leaning toward poured foundation w 2" xeps on outside for basement and 2x6 w wet cellulose, 5/8 plywood, and 2" foil polyiso or xeps. partial brick veneer and hardiplank. Still in design stage....Eric

Don't expect ICFs to be competitively priced with wood framing, they are not comparable. Anything better is usually more expensive.

Consider InSoFast for a regular poured foundation wall.

Its really good to know about your home, you can take it easy things will be settle down in some days, you need to contact wit some service provider or put some pictures of your house there, it will be good for us to suggest you better plan.