The Forestry Forum

General Forestry => Timber Framing/Log construction => Topic started by: Yoter on October 23, 2021, 09:33:37 PM

Title: Yoter's Cabin Design Thread
Post by: Yoter on October 23, 2021, 09:33:37 PM
After a lot of back and forth I finally decided that a log cabin would be the best solution for my back field guest cabin/office/retreat for a variety of reasons including the build advantages of simply stacking up walls and being able to build something with a look reminiscent of an old Appalachian cabin:

(https://forestryforum.com/gallery/albums/userpics/33922/Hall_Cabin_Front_Elevation.jpg)

To build my simple 16' x 16' box I'm thinking of using these 6" x 12" milled flat faced logs:

(https://forestryforum.com/gallery/albums/userpics/33922/Log.jpg)

 with a chink joint and hewing marks:

(https://forestryforum.com/gallery/albums/userpics/33922/LogII.jpg)

The logs can also be dovetailed at the factory as well.  Maximum length is 16' so my current plan is to buy all 16' logs dovetailed to stack as high as I need and then some plain end logs to stack the gable end walls:

(https://forestryforum.com/gallery/albums/userpics/33922/LogIII.jpg)

I definitely want to darken the wood as much as possible-ideas?  Also need suggestions on chinking.  The basic anatomy of the cabin would be as shown below.  I think it makes the most sense for me to bring in commercially bought logs to make up the bulk of the walls, but I should have more than enough black locust on my property to supply beams to support the loft, a ridge beam and rafters, flooring for both the loft and the ground floor, and partition walls as needed:

(https://forestryforum.com/gallery/albums/userpics/33922/Hall_Cabin_Cutaway.jpg)

The cabin will be built upon an existing concrete block stem wall foundation that once had a 16' x 32' henhouse on it-bad picture but you get the idea:

(https://forestryforum.com/gallery/albums/userpics/33922/Foundation.jpg)

The plan will be to fill the gaps in the walls that were presumably there for doors by blocking them up with concrete block and mortar and then filling all of the voids with concrete, driving threaded rod all the way down through the cells every few feet and leaving it sticking up through the finished slab so that the first three or four courses of logs can be drilled and lowered onto the rods and bolted before continuing to add courses.  The interior of the foundation will be filled with 3/4" minus stone compacted in lifts until its flush with the block all the way around the perimeter-should be about 25 yards of stone.  Then I'll form up the sides with lumber, put down reinforcing wire, etc...and pour a 4" slab over the entire thing.  I figure it should be nice and strong with all of the block voids filled and a nice thick slab over top.  Conduit and pipe will be placed before the pour for power, water and ethernet in and waste out.  Heat and cooling will be provided by an 18K BTU mini split which should be more than adequate given the square footage, but of course there will be a small woodstove for supplemental heat sitting on a hearth made from stone on the property.  The service will be a 100A subpanel with the biggest power consumers being the mini split, the refrigerator and the macerator pump.  LED lighting loads, TV and computer should be minimal.  A 100lb propane tank will supply the stove:

(https://forestryforum.com/gallery/albums/userpics/33922/Hall_Cabin-Main_Floorplan.jpg)

The loft will be accessed by a ship's ladder and will fit a queen sized bed.  Ironically its almost the same size as the master bedroom in my first house  :D

(https://forestryforum.com/gallery/albums/userpics/33922/Hall_Cabin-Loft_Floorplan.jpg)

I'm struggling a bit with the beams for the loft.  The idea is to mill some nice heavy 8" x 12" beams from black locust which will span the width of the cabin and will be mortised into the logs giving them plenty of bearing area on either side.  However, the ship's ladder interferes a bit and makes for 4'-5" of unsupported area between the beams.  I'm planning on milling my black locust floor boards 1-1/2" thick, but I don't know if its going to be stiff enough to span that far without feeling very bouncy?  Relocating the ship's ladder isn't ideal either.  I'd be very interested in some feedback on that.  

(https://forestryforum.com/gallery/albums/userpics/33922/Hall_Cabin_Loft_Framing_Plan.jpg)

On the subject of beams, for the ridge I'm hoping to mill a 20' long 8" x 12" so that it can be flush with the gable wall in the rear and protrude prominently in the front.  There would only be one set of actual "rafters" as the gable end rafters will be fully supported by the logs.  The rafters in the middle will be 6" x 10" and 4" x 6" purlins will be mortised in perpendicular to the rafter's outside face (not laid over the rafter on the long edge like a typical purlin) which I'm hoping will be stiff enough.  The roof will be simple ribbed steel-I haven't settled on ceiling insulation and interior finish yet-could use some suggestions.  Ideally I'd like to break ground on this project in late spring/early summer next year.  Until then I'm hoping to kick around ideas, get some constructive criticism and really dial in the design.  


Title: Re: Yoter's Cabin Design Thread
Post by: Don P on October 23, 2021, 10:11:37 PM
You have a foundation of that square footage, why go up.
Title: Re: Yoter's Cabin Design Thread
Post by: kantuckid on October 24, 2021, 08:59:19 AM
There's a bunch of ways to darken wood/logs using stain or chemicals. They also sell that magic powder you mix with water to age wood- turns it brown like barnwood. Sold on ebay and also can be found cheaper on the web-I forget what the goodie content aspect it has in it?
Darkening the logs is one thing-protecting them for the long term is not always the same thing which is why I'd use a stain that does both. If you run some tests be certain that you use the exact same means/rate of application as you'd apply the stain (or whatever you use)  to the actual house or you might experience a much different level of color intensity.  
You ask about chinking but show a stack log build which uses caulking and/or foam gasket material. Your buying milled logs which can be milled to create a chinking gap-decide which it is before you arrive at your final design as it obviously affects wall opening details and heights as well. 
Title: Re: Yoter's Cabin Design Thread
Post by: Yoter on October 24, 2021, 09:09:22 PM
Quote from: kantuckid on October 24, 2021, 08:59:19 AMThere's a bunch of ways to darken wood/logs using stain or chemicals. They also sell that magic powder you mix with water to age wood- turns it brown like barnwood. Sold on ebay and also can be found cheaper on the web-I forget what the goodie content aspect it has in it?  Darkening the logs is one thing-protecting them for the long term is not always the same thing which is why I'd use a stain that does both. If you run some tests be certain that you use the exact same means/rate of application as you'd apply the stain (or whatever you use)  to the actual house or you might experience a much different level of color intensity.  You ask about chinking but show a stack log build which uses caulking and/or foam gasket material. Your buying milled logs which can be milled to create a chinking gap-decide which it is before you arrive at your final design as it obviously affects wall opening details and heights as well.
Gotcha-was also going to look into charring the logs a bit with a torch?  I know I saw some threads here in the past about that.  Not to the point of the Japanese method where the wood actually gets that "alligator skin" look, just a subtle darkening.  I think it also has some preservative properties as well?  As for the chinking, it will be purely ornamental-the logs I am looking at have a false chinking gap milled into them.  

Quote from: Don P on October 23, 2021, 10:11:37 PMYou have a foundation of that square footage, why go up.
When I pour the slab it will be 16' x 32' and the cabin will be 16' x 16' so I'll have an adjacent 16' x 16' slab to utilize for something else.  The photo I posted of the foundation was from when we first bought the place.  There is now a large vegetable garden to the left of the foundation and to the right there is a fenced in area about 32' x 40'.  I thinking of putting up a combination chicken coop and gardening shed on the rest of the slab with some space in between that and the cabin.  Also, I've just always wanted something with a loft sleeping area.  Another change from the photo is that the treeline and heavy brush in the background of the foundation is now mostly gone and there is a nice view of the pond below.  I'd like to have a nice high view from the loft of the pond.
Title: Re: Yoter's Cabin Design Thread
Post by: Runningalucas on October 24, 2021, 10:11:53 PM
To darken the logs as you said, burn them, and oil them; you can also use diesel with a varying amount of tar mixed in, or even used motor oil. 
Title: Re: Yoter's Cabin Design Thread
Post by: Yoter on October 25, 2021, 07:40:19 AM
Quote from: Runningalucas on October 24, 2021, 10:11:53 PMTo darken the logs as you said, burn them, and oil them; you can also use diesel with a varying amount of tar mixed in, or even used motor oil.
I think I'll start by experimenting on the logs with my weed torch and go from there.  I'm sure the diesel/WMO would be effective but I'd be concerned about the smell.  My tractor barn smells strongly of diesel and WMO which is fine for what it is, but I'm not sure I'd want to sleep in the loft  :D
Title: Re: Yoter's Cabin Design Thread
Post by: Don P on October 25, 2021, 09:44:54 AM
Just stuff to think about, take it or leave it. I've built places with small lofts like that, they are miserable and several times I've heard regret expressed. A tree house is fun for a weekend, which might be all this is.

A dogtrot with an open center pass thru came to mind when I saw the foundation and individual floor plans. In any event I'd think of isolating the indoor/outdoor slabs, probably in elevation for driving rain as well as thermally. The cold edge can track inside feet in the winter on a continuous slab.
Title: Re: Yoter's Cabin Design Thread
Post by: Yoter on October 25, 2021, 10:55:52 AM
Quote from: Don P on October 25, 2021, 09:44:54 AMJust stuff to think about, take it or leave it. I've built places with small lofts like that, they are miserable and several times I've heard regret expressed. A tree house is fun for a weekend, which might be all this is.

A dogtrot with an open center pass thru came to mind when I saw the foundation and individual floor plans. In any event I'd think of isolating the indoor/outdoor slabs, probably in elevation for driving rain as well as thermally. The cold edge can track inside feet in the winter on a continuous slab.
With regard to the loft, a "weekend treehouse" is a somewhat good description of what this will be, but again, it is the about the same size as the master bedroom in my first house, which my wife (at the time) and I actually squeezed a king bed into  :D  With regard to isolating the slabs-very good point.  It would not be difficult to do so.  As for the interior floor of the cabin I was thinking of shooting down nailer strips to the concrete every 24" and doing rigid foam board insulation in between, then securing the locust flooring planks to the nailer strips.