Friday, April 9, 2010

Making Concessions

I'm rounding the homestretch on the 16' x 24' cabin plans. The end is in sight. After months of designing and redesigning, I've finalized the structural plan enough to start working on a materials list, finding suppliers and costing things out. And then going back and tweaking my model with necessary changes to stay somewhere close to our budget.

For instance, we'll have to forego the metal roof this time and go with shingles. It's not ideal, and won't make for good rain catchment... but we can afford it and it doesn't rain here enough anyway. The nice enclosed porches that could be turned into arctic entries every winter with a few foam panels? Those had to be post-poned as well. All the other niceties, like big windows in the living room and tongue-n-groove flooring, don't really result in enough cost-savings to eliminate.

So I feel that I've stripped down the design and construction of the cabin to barest of bones, with the absolute least amount of material waste, while still maintaining a safe, livable, and warm abode. Designing the whole thing on a 4x8 grid to match common building materials helped keep costs down ALOT, even if it made building the stairs a total PITA. It's been a challenge, but worth every minute.


What we've ended up with is a box made of 6x12 (everything yellow is 12") sill beams and girders, that rests on our piers on top of adjustable screw jacks. The 6x6 posts go on the sill box frame and support an identical header box frame creating the loft and supporting the gambrel roof. This is the main load bearing structure and more than adequate to handle the loads - including snow, wind and seismic (whew! doing all THAT math sucked!)


The concrete pad and pier foundation is completely on the surface because of the permafrost, and the crawlspace is 36" above grade to keep from thawing it out. Between the concrete piers and the sill beams is an adjustable heavy-duty (15-ton bearing/2-ton lifting) screw jack so that we can level the house in the spring and fall if there is frost heave. That's one of the reasons we had to build such a beefy load bearing frame for the main "cube" -- can't have the house joints bending and flexing too much while we're twiddling with the jacks.

Between the wall posts, we'll be installing a double wall, with a gap between, made of 2x4 studs that are staggered 24" on center (no thermal bridges!) and then the entire 8" cavity filled with blown cellulose (for about R-30). The 12" floor and rafter cavities will also be completely filled with cellulose (for about R-45).

The south end of the first floor is the living room and kitchen area, with the woodstove centrally located. There are 3 big windows on the south face (2 down, 1 up) to let in light and some tiny bit of solar gain in the winter (but mostly they will have thick insulating curtains on them in the winter to keep in the heat).


The north end of the first floor contains an 8x8 pantry for all our non-freeze-safe food storage needs (since we stock up for the entire winter), and the staircase (I don't trust ship ladders because I'm a spaz) with our composting toilet and a sink (yes, a real sink!!!) underneath. There is a small ventilation/light window in the bathroom under the stairs, and a fixed glass picture window upstairs (we couldn't ignore the view of the mountains even if windows on the north face are a bad idea).


The loft will have the bedroom, our water storage tank, the battery bank & inverter and (finally!) a small office/desk area. The super-steep (12/3 & 7/12 pitches), braced gambrel truss roof allows us to have almost full usable floor space in the loft, even if it requires a ladder permanently affixed to the roof so we can get up to sweep the chimney.


Both porches on the east and west side are 4' and we will be screening them in even if we don't fully enclose them yet. The porches will be used to store firewood, the generator, fuel and to set up our little propane burner so I can do my canning without totally heating up the house.

So that's the plan anyway. Next time we're in Fairbanks, we'll place our orders at the lumber yard and builders supply warehouse and should (hopefully) have the rest of the driveway and homesite cleared before they deliver everything to the side of the highway. No one will come down our trail in a big truck, not even for the pricey delivery fees  :(  Oh well, at least I won't have to drive back and forth to Fairbanks a dozen times ferrying it all 3/4 tons at a time!

Now let's see if we can build it level, square and plumb; and get it all dried in and insulated before winter comes again. :)  It'll be nice to have solid walls again.

12 comments:

Chris said...

Hi PC,

I've been quietly following your blog for almost six months now and I thought it was about time that I said hello and thanked you for your very interesting discussion - I wish you both every success in your amazing adventure. I live in the UK and share many similar interests with you and Gungnir. I've also seen your posts on the Forestry Forum - I'm also considering the purchase of a sawmill, what did you finally decide to do?

Looking at your cabin design, I can't help but think that you should also jack the outer columns that support the porches otherwise the porch floors will twist and buckle as you raise/lower the main structure. I fully appreciate that it will add extra cost but you will kick yourself whenever you see large cracks and bows appearing in the porch floors.

HTH,
Chris

Plickety Cat said...

Hi Chris, thanks for following us :) (in a non-stalker-ish way, of course LOL)

We're going to go with the Granberg Alaskan Chainsaw Mill since it's the right size for squaring up our timbers and slabbing out the few planks we'll need for the big house. One of the other mills might have been faster, but a CSM works fine for what we need to do and the smaller amount of projects we're going to use it for.

The "pyramid" concrete piers for the porch posts also have an adjustable screw jack on them; just the regular 4x4 "wimpy" ones common for decks, not the super-screws that we're using on the house beams. We can fiddle with the porch independently of the house since the joint between the two is pretty flexible; just so long as we don't tear the roof joints apart! It's not as critical to keep the porches completely square and level, at least not until we enclose them and get the doors on.

Anonymous said...

I know you said you cant afford the metal roofs but have you looked into the tin, like the old tin roofs. There are a lot of them here and a lot of them up there due to cheeper cost. Just a thought. Was what our roof was up there when we did water collection. Just a thought...

Washkeeton

Lindsay said...

I can't remember how I stumbled across your blog, but here I am. :) Not sure if you'd be interested in this or not, but I have a bunch of new drywall for a reduced rate. It's currently in Cooper Landing, but could easily be brought up to the Anchorage area. If you're interested in hearing more about it, email me at bkstrk3 at aol.com. Thanks, and good luck - your plans sound exciting!

Jason Jensen said...

Wow now that design looks a lot better than what I thought you guys where going to do. I hope all is well.
hows all the animals doing?

Walkntom said...

I have waited for your designs for some time and now that i see them I know why I waited. All my thinking in building something other than a log house/cabin has been this very design. Just from a cursory look the gambrel roof seem the most logical whether you are looking at snow bearing, rain catchment, best utilization shape/space ratio or installation of photovoltaic panels.

So, what would you charge me for these plans plus the materials sheet? How hard would it be to increase the overall size?
What are the functional dimensions of the loft?

Quinton said...

You have "bit off a lot to chew" for one short summer. Are your trees big enough to make framing and boards for the main house if you had a sawmill to cut them with? I might consider a trip to Alaska next summer with my sawmill. Food for thought. Is all of the ground permafrost? How did they build a city as big as Fairbanks on permafrost?

Plickety Cat said...

Quinton - we do have timber that is large enough to square up into beams and get some decent planks and lumber out of, and we're planning to get an Alaskan CSM for that because it works for our situation. Now, if you feel compelled to come visit and want to bring your mill with you, I certainly wouldn't argue :)

This area and Fairbanks has discontinuous permafrost, so it's either patches or it ebbs and flows from year to year. In the city, for larger buildings and such, if they're on permafrost they tend to use a steam borer to melt the PF to sink footings/pilings really deep. But most times, they try to find the areas free of PF and pour a standard foundation. Since we're out in the boonies and our place isn't big, it's too cost-prohibitive to steam-bore or get a full geo-tech soil survey.

Jon Anderson said...

I've never been much of a fan of the grambrel roof. But after following your posts, I'm starting to see the value of that design.

Alaskan mill works fine if you have time. I've used one for most of my cabin work. I flatten quite a few logs using the mill. I've found that the alaskan micro mill works best for flattening one side, then, I use the CSM to rip the timber the correct depth.

I ended up purchasing a 97 cc saw to run with my CSM. The 65 cc worked well, but the big saw works much better. Also, square ground skip chain made a huge difference.

Good luck. Hope the weather is getting good for you. Stay safe.

Foster Family said...

I like your house! Of course, I think I should, it looks a lot like our home! http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=72715515&albumID=833318&imageID=4420273

Although this home is in Oregon - not Alaska! Love your blog!

Anonymous said...

do you have a website with more details on this cool home

Gungnir said...

Yup you're on it...