Building for cold and wet - 20x30

[Nevada_Mike]

I have been lurking for some time appreciating many of your comments.

Well.... here I go.  I have the 20x30 1.5 plans and I am meeting with the local contractor in a small Southeast Alaska town in March.  The foundation will go on the ground then! The winters are fairly mild and very wet! Summers are wet also. The local builder wants to pour a footer 6x18 on grade with a 6 inch stem wall out of that.  From there we will build a yellow cedar stem wall to the height that I desire. I wanted a full concrete stem wall but he advises that a well built and ventillated stem will stand the test of time and cost less. Concrete is "grey Gold."

My pad is rock approximately 48 inches thick with a gentle slope to the ocean. Here are some of the other particulars that I would like comments on.

Spruce and hemlock framing
Tar paper barrier followed by Yellow Cedar ship lap
Some type of shear under the felt
Metal standing seam roof
No power yet - will sit for months at a time
Normal non low e windows

Thanks for comments!

[Shelley]

Mike,

All the wet guys have evidently gone to bed or out to dinner.

I don't do wet.  Most of the people here seem to be from the NW or SE.  They do wet fine.

Someone will be with you shortly I'm sure.

[Amanda_931]

Not sure I do wet either.  Or, for that matter really dry.

Is some of this "stem wall" in a basement?  what's the floor made of?

Why not-low-e windows?  You would get better solar heating without them in everything but deep winter (People were posting Alaska noon pictures on Wunderground around the solstice!--but they may have been a LOT farther north than you are).  But you would need night-time insulation, insulated curtains or maybe storm windows.  

Are we talking no running water, so you can leave the place empty for months?

[Nevada_Mike]

All of the foundation will be above ground.  It is also a very mild climate with only a few days a year below freezing. It is know as the "suburbs of Seattle".  As far as the water goes it will be a while for running water.  I will put in a whole house drain when I do that.

[DavidLeBlanc]

Seattle calling - where this winter has been far from our typical wet one!

For a Nevada guy (or even much of the US), our 30-40"/yr probably does seem "wet". However, there's wet, and then there's wet!: In the rainforest, not 40 miles away, a typical year's rainfall is more like 140-180"/yr! (a lot of which went to Disneyland this year! ). There are also places within 10 miles of the rainforest, in the rain shadow, that only get ~15"/yr - that includes the San Juan Islands! The Pacific Nortwest, especially the coast, is a patchwork of micro-climates like this!

One thing I can think of offhand that's important in a cool, wet climate is wide eves and covered porches. That way, the walls of the building get some protection and there are places to go outside that are covered - if you let rain control your coming and going, you won't like the PNW or coastal Alaska much. Umbrellas and brimmed hats are not a fashion statement here!

Sooo... you'll need to know what the annual rainfall is at your particular specific location to know what kind of "wet" you're dealing with!

Another good thing is to put hoods over the windows to allow them to be open a little in rain or (much, much more typically) misting conditions. See the "
 Here's an illustration of a window hood, as seen on our host's "Builder's Cottage" as an optional trim detail:

In the perspective, on the right, window hoods are shown over both windows on the left side of the cottage (of course, on the side windows, a wider roof overhang would achieve the same effect). Ah, an "oh duh" moment: good air curculation is a must: otherwise it's going to be mold and mildew city, both of which thrive on damp, still air. "Tight" closets and cupboards are not your friends!

Put a vapor barrior, like you really mean it, between the foundation and the underside of the house!!! It's another place that needs to be well ventilated - and well screened to keep 4-legged "tenents" out too! Squirrels, chipmunks and (ahem) skunks like dry spaces too!

Oh yeah - you might just need more heat than you think you do - unless you want to install air handling and dehumidification. Humidty leaches heat out of the air fast (your first year in AK will be a test of your dryland accustomed circulation system - yours (NV) would be for me too!).

[Nevada_Mike]

I think that the rain amounts to over 200 inches per year. LOTS. As far as the vabor barrier are you saying to place the barrier between the top of the stemwall and the floor joist or on the ground. My intention was to place the vapor barrier on the ground. I have read in several places to not vent the crawl space to the outside at all but rather to seal it very well and vent it to the interior of the house. I plan on venting it to the outside.

[DavidLeBlanc]

I think it should go on the ground (or slab?) and then covered with a couple of inches of coarse gravel to keep it in place and avoid critters that happen to get in from messing it up. Between that and the underside of the house, I would arrange for good cross ventillation that is not vented into the houses' interior!

[John Raabe]

I agree with David. I would do a vapor barrier (6 mil black poly) over the crawlspace soil. It can be covered with gravel or sand if you will use the space for storage.

I would also vent the crawlspace (perhaps closable in winter - you can see if the place gets too humid if closed up). Then insulate the floor above. Don't put a vapor barrier on the bottom (crawlspace side) of the floor insulation. An air barrier such as Tyvek is a good idea however and will help hold the insulation in place.