Planning a simple cabin roof

[Ernest T. Bass]

Hi all!

We're tossing around ideas for making a smallish rustic cabin this summer... Probably an Aspen vertical-log style building. We're planning on making a frost-protected perimeter earthbag foundation, with high enough stem walls to get the logs well off the ground. I like the idea of placing the vertical logs to the height of the top of the doors and windows, and capping them with a couple rows of horizontal logs. Seems like it would give the unstable-ish vertical log walls a lot more racking strength, and eliminated the need for headers and stuff..

Ok, on to the roof.. We need it to be cheap and easy. We would also like a vaulted ceiling. I'm thinking of rustic round-pole rafters and tie beams, decked over with exposed 2''x lumber. A vapor barrier would go over the wood, then about 6'' of beadboard (cheaper, somewhat environmentally benign as far as foams go...). 1''x strapping would be screwed to the decking through the foam, and metal would go on the strapping.

Does this sound like a feasible plan? I know that 6'' of beadboard isn't a whole lot of insulation, but we are only talking about a cabin. I think the vapor barrier would be a good idea, even with the rigid foam, right? One concern is the expense of the 8''-10'' fasteners needed to reach through the foam. Is there a better way to do this, possibly with extra strapping between the layers? Also, how well braced is the roof going to be, with the metal being so separated from the deck? Might it be a good idea to put the 2x decking over the rafters on diagonally? Could be an interesting effect on the inside..

Thanks for your input,
Andrew

[glenn kangiser]

Sounds like an interesting project, Andrew.  What about bracing for the walls --Throw in a couple Diagonal braces?  Just thinking that the vertical logs would not give much diagonal bracing.

I think fasteners can be shopped for -- I found 3/8 by 12 lags for $2.50 each but when I went to my wholesale supplier in Fresno, they were 0nly $.38 each

[Ernest T. Bass]

Wow, that sounds like a good supplier... I doubt we could find deals like that up here. 

I wonder about using 1x3 strapping in each layer of foam, screwed down perpendicular to the strap on the layer below it to get away with shorter screws.. Cheaper, but more work and possibly not anchoring the metal roof as well?

I haven't read anything on diagonal bracing for the log walls... I plan on using plywood splines and glue at each joint + rebar/barn spikes, so I think that they couldn't really shift against each other.

[glenn kangiser]

You might get a quote from them.  They ship.  Mid Valley Distributors in Fresno.

http://www.midvalleydist.com/

Rebaring them should give you a good brace section.

[Ernest T. Bass]

I'm gonna hijack my own thread and ask a quick question about the Aspen logs...

As far as hauling and drying the wood goes, the best time to harvest the trees would be right now.. I'm just afraid that they would be impossible to peel. I'm wondering, will the bark still peel off easily in the spring thaw even if the trees have been cut down now?

[MountainDon]

Doubt it.

[glenn kangiser]

When the sap is up in the spring is a decent time to peel but hard work on Pine.  A year or so later the wood shrinks away and the bugs have worked the cambium layer to loosen the bark.  That is the easiest time.

I don't know about Aspen.

[Ernest T. Bass]

We've had Aspen start to rot after a year with it's bark on.. That stuff practically self-degrades. It's super easy to peel the trees in the spring when they are green (you can use your fingers), but I would like to start chopping now.. We plan om building in the spring, so we could get a head start and let the wood dry for a while if we cut now.

Also, cutting the sap-filled trees in the spring and letting them season in the humid, shady woods sounds like a bad idea, as the Aspen will turn black in a matter of weeks... We plan on dunking them in a salt brine as a temporary fungicide, but letting them season in the winter just seems like a better plan to me (so long as we can still peel them in the spring..).

Sorry for the rambling... So many ideas right now. I'm sure you'll be hearing a lot of questions before this project comes together.

Oh, I was also thinking about the foam on the roof... Maybe we could lay down 2'' of eps, strap it down with 1'' lumber and 4'' screws, lay 1'' of foam between the strapping, put down another 2'' of foam and then another layer of 1'' strapping placed perpendicular to the wood below it. So, 2 layers of 4'' screws, vs. 1 layer of 8'' screws. Could be cheaper..

Anybody know where to look for scavenged eps? Odd-shapped cutoffs, leftovers from a job site, etc? I'll have to check with the local contractors, but I'm not really keeping my hopes up..