Photobucket

Author Topic: building log cabin roof  (Read 4360 times)

Offline surfivor

  • Survival Demonstrator
  • *******
  • Posts: 2768
  • Karma: 30
building log cabin roof
« on: November 06, 2010, 09:01:25 AM »

 I have been studying some books I have on log cabins ..

The part to me that I am not sure or seems tricky is the purlins and roof rafters - how to get those to line up evenly so that a roof could go over them ..

 If you use logs for rafters, they are obviously not perfectly shaped for instance .. it's not obvious to me how to get that to work out and the sides are logs as well ..

Offline rustyknife

  • Dedicated Contributor
  • ******
  • Posts: 1010
  • Karma: 28
Re: building log cabin roof
« Reply #1 on: November 06, 2010, 11:27:58 AM »
In most cases if you go 100% log construction you will end up with some unevenness in the roof system. I have seen where the original builder would notch or releave the rafter so that the purlin would sit better. That is a tricky operation as you don't want to cut away too much of the rafter. About the best straight forward job I've seen was where they laid the purlins over the roof rafters so that the big end or stump end of the purlin was the overhang at the end of the building and the taper went to the center. Then they did the same thing from the other side of the structure; the stump end is the overhang and the taper towards the middle. The two purlins would pass each other and be lashed or nailed or bolted together. Depending on the spacing of the purlins they don't have to be of large diameter. If you already have a set of plans follow their recommendations. Good luck with your project.  :D Would love to see some pictures of your progress.
"Those who expect to reap the blessings of freedom must, like men, undergo the fatigue of supporting it." Thomas Paine

"Survival is a form of rebellion, living is the punishment" Mr. Smith from the movie "The Way Back"

"Those who would give up freedom for a little security deserve neither" Ben Franklin

Ride hard as you can, rest when you die
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thouroughly used up, totally worn out and loudly proclaiming "man what a ride!" Author unknown

Offline surfivor

  • Survival Demonstrator
  • *******
  • Posts: 2768
  • Karma: 30
Re: building log cabin roof
« Reply #2 on: November 06, 2010, 11:40:16 AM »

 I don't think I would be able to start on this until next summer except maybe cutting some trees.

I saw plans for a 9x12 cabin. The small size may mean smaller logs to move which seems like a challenge in itself.

 I guess 2x6 rafters would make some of that easier, but yea roof unevenness I guess may come with the territory on that ..

I have a couple of books, but there always seems certain details are not covered in depth and that may have been one of them ..

Offline rustyknife

  • Dedicated Contributor
  • ******
  • Posts: 1010
  • Karma: 28
Re: building log cabin roof
« Reply #3 on: November 06, 2010, 11:49:12 AM »
Not sure where you live but as a suggestion I would recommend looking around your area and see if there are some surviving structures that you can spend some time at. Take a camera and some notebook paper for notes and sketches. Sometimes you can get the same information from old barns.  Another fun thing to do is build a miniature version of what you want. You could use some small sticks and a pocket knife. It's a fun way to actually see how all the parts fit and interact with each other.
"Those who expect to reap the blessings of freedom must, like men, undergo the fatigue of supporting it." Thomas Paine

"Survival is a form of rebellion, living is the punishment" Mr. Smith from the movie "The Way Back"

"Those who would give up freedom for a little security deserve neither" Ben Franklin

Ride hard as you can, rest when you die
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thouroughly used up, totally worn out and loudly proclaiming "man what a ride!" Author unknown

Offline NWBowhunter

  • Survivalist Mentor
  • *****
  • Posts: 824
  • Karma: 23
  • Got Elk!
Re: building log cabin roof
« Reply #4 on: November 07, 2010, 12:54:53 AM »
I think alot of the uneveness can taken out by using a draw knife to shape your rafters to the same size. Plus in most case the trees are taken from a stand that is of the same age so most of them should be similar size.
I'm prepared to be wrong are you?

Offline hillclimber

  • Dedicated Contributor
  • ******
  • Posts: 1095
  • Karma: 28
Re: building log cabin roof
« Reply #5 on: November 07, 2010, 09:00:02 AM »
You can do alot of the fitting work with a chainsaw. If you use regular logs, not milled, you're gonna have to chink it up anyway.
"A shotgun, a rifle, and a 4 wheel drive, a country boy can survive"

Offline surfivor

  • Survival Demonstrator
  • *******
  • Posts: 2768
  • Karma: 30
Re: building log cabin roof
« Reply #6 on: November 08, 2010, 01:59:46 AM »

 From some pictures I saw, it appeared the purlins support the rafters as well as the "A" shaped side wall. Some of the logs on the side wall did not appear to have purlins or any connection to the adjacent wall which to me would seem undesirable. It seems a bit tricky to line up everything since there are several things going on. I have sort of a vague idea of how you might go about it.

A purlin can be made level with itself and the purlin on the other side of the "A".

A straight board can be used to position the purlins as you go so that they line up with where the roof slant would go .. as well as some sort of angle mechanism such as make sure it 45 degrees etc ..
 
 I would imagine every side log should be notched so that it either sits on a purlin, or a purlin sits on it. If you had 8 inch logs, that would mean you might have close to one purlin for every 1 foot of vertical rise .. The cabin pic I saw I think the "A" part rose up 4 feet from the base wall (for a 12x9 cabin). They showed 2 pairs of purlins plus the rafter so it was a lless than a purlin per one foot, but they showed one log that was not connected to a purlin in anyway which I'm not sure about ..


Offline joeinwv

  • The Bee Whisperer
  • Survival Demonstrator
  • *******
  • Posts: 2556
  • Karma: 90
Re: building log cabin roof
« Reply #7 on: November 08, 2010, 10:44:57 AM »
If you are using green wood off your own property, it doesn't matter how perfect you set it up - it is going to settle and shrink regardless.

For a 9*12 the A part is either a rafter on each end, or you just use shorter logs to make the A shape. Your purlins go on top of the rafters. Then cover with plywood, boards, etc and shingles.

Offline surfivor

  • Survival Demonstrator
  • *******
  • Posts: 2768
  • Karma: 30
Re: building log cabin roof
« Reply #8 on: November 08, 2010, 01:19:00 PM »

this is sort of what I imagined, except there is a lot more space between logs .. I guess it gets filled in with moss/insulation ..
but each purlin is both on top off and under a log ..



 getting the logs way up there seems like a problem in itself ..

Offline joeinwv

  • The Bee Whisperer
  • Survival Demonstrator
  • *******
  • Posts: 2556
  • Karma: 90
Re: building log cabin roof
« Reply #9 on: November 09, 2010, 12:54:57 PM »
The space is filled with chinking - today this is an elastometric product, like caulk. Traditionall, this would have been lime, clay, etc - more like mortar.

Offline hillclimber

  • Dedicated Contributor
  • ******
  • Posts: 1095
  • Karma: 28
Re: building log cabin roof
« Reply #10 on: November 10, 2010, 04:46:47 PM »
I remember a documentary on PBS a few years back where a profesional photographer moved to Alaska and built a log cabin all by himself with hand tools. He had it pretty well figured out. As I remember, he cut and peeled all of his logs a year ahead of time. By the time he was ready to build they had dried, weighed much less and had already shrunk.

Wish I could remember the name of that movie....
"A shotgun, a rifle, and a 4 wheel drive, a country boy can survive"

Offline Mick

  • Fledgling Prepper
  • *
  • Posts: 9
  • Karma: 1
Re: building log cabin roof
« Reply #11 on: November 27, 2010, 09:16:40 PM »
Great documentary, "Alone in the Wilderness."

http://www.dickproenneke.com/

Offline Dan

  • Survivalist Mentor
  • *****
  • Posts: 976
  • Karma: 41
  • MSB Founding Member
Re: building log cabin roof
« Reply #12 on: November 27, 2010, 09:39:14 PM »
Great documentary, "Alone in the Wilderness."

http://www.dickproenneke.com/
Thats the one.

I watched this on PBS in a motel room while on vacation a couple years ago. I liked it enough that when I got home from the trip I ordered it and the follow up video "Alaska Silence and Solitude". Both good videos. If you are interested in building your own cabin I would recommend Alone in the Wilderness for motivation but I don’t think there are many building tips to be had.
 
"Tu ne cede malis sed contra audentior ito"
"Do not give in to evil but proceed ever more boldly against it."
Virgil's Aeneid, Book VI