Introduction: Convertible A-Frame Cabin
This cabin I built on a quiet hill and it would probably make Thoreau proud. It's based on a standard A-Frame but with a convertible wall similar to one done by Deek, David Stiles, and Joe Everson. I've added a couple of features of my own and left out some options that didn't add much to what I needed. My total cost for materials was about the same as theirs, so it was easy to budget.
I'd rate this as an intermediate build due to keeping the angles the same, installing a level horizontal hinge and mounting a door but not very complex beyond those basic concepts. It's a very flexible design if you want to go a little taller or shorter, longer or narrower it will easily scale a bit to fit any need.
Over two years of use and still enjoying it for daytime serenity, wildlife watching, over night camping or just hanging out with friends. I hope you build one and enjoy it too.
Step 1: Site and Foundation
Any structure needs a good foundation and every site will vary from any other.
The place I chose was on an slope with large exposed rocks so the biggest part was getting things level for the base to build upon. I used concrete blocks to rest the base on. For the part farther down the hill I used 4x4 posts on pre-cast piers. All this is the same as if you are building a free standing deck. Use a large level and check in multiple directions to help ensure you have things level.
Another aspect of my project was to save a little cost by using shipping pallets. This experiment to see how practical they are for building construction, ease of use and how long they can last. Getting pallets that are suitable dimensions for your project may not be reasonable. I had access to a lot that just happened to measure up exactly to what I needed if I used two different sizes, one being slightly wider on one side. Also they were in great shape. Aside from my experiment you should just plan to build this as a deck with more 2x6 joists, one every 12 inches.
In the first picture you can see how I used blocks to counterweight a support as I framed the deck so all the foundation elements are inset for a cleaner look. The final deck is 17'x10' with a 10' 2x6" joist between each row of pallets. I used 3" construction screws for all the deck and framing, build it to last. Since the cabin walls rest on the outer band I can unscrew the flooring anytime and replace it.
Step 2: Framing
My plan settled on a cabin base that is roughly 10' by 12' and the key desire was to use a standard exterior 30 inch door. This gave me a hypotenuse of 13'6" and an angle of 66 degrees. Use an angle finder to check once you are set on your own plan.
I made angled cuts on five 2x6", one for the middle on the non-opening side and most importantly a pair for each end. Aside from the angle at the top you also need a 3/4"x 5.5" notch inset, this will be for the top rafter to fit into the top of each A on the ends. Fix the angled ends together and add a gusset temporarily on the outside face so they don't flex while you are raising them and to help position the top beam. Another 2x4 about halfway down also helps as seen in the first picture.
On the base I put a couple of 2x4 stubs (picture 2) where the feet would go to make it easier to set in place and then screw in temporarily while finishing out framing. You will certainly need a helper for raising the frame in place and I tied ropes to each side of the A's so they could be held in place until framing was completed. Plywood is cut so it overlaps the deck band and it then its the permanent support holding the vertical wall up.
Normal framing elements are used for the rest of the wall with a key being to consider the plywood and roofing material you choose before setting out to frame those parts. The material you choose for roofing will determine how often it needs to be attached. Under each space for screws or nails you'll want to have a 2x4 receiving them. Else you'll have many points sticking through to the interior. Alternately you could fully frame in that wall, insulate it and have a second layer of material inside and never see any nails protruding, though it will cost you several inches of space.
Step 3: Opening Panel
This is the step that makes your cozy 10x12 cabin into a covered outdoor observation platform.
It's optional but most rewarding and needs only some careful attention to placing the hinge. It's possible to use normal door hinges but those will be difficult to align when spanning ten feet, you'll need several of them and need to incorporate them into the woodwork, also you might possibly find a large piano hinge. Either will work but can add to the cost. A 10' steel pipe can be had for about $15 and using a paddle bit that matches the diameter of the pipe means you can just go through 2x4s. I used three for the uprights on the moving panel and then drilled about 1" into the wall frame (picture 2). Drilled through a couple of short boards and attached them at the center to prevent sagging. One important thing here is that I inserted the pipe from the outside (picture 1) so I wasn't able to put the upper siding on until the hinge was in place.
Basic framing finishes out the panel with attention to cutting the bottom at an angle so it mates up with the floor when closed. Five panels of Tuftex completed this wall and with my south facing exposure it gets a bit of heat gain during the day.
Use a flexible piece of rubber like shelf liner or conveyor belt to cover the gap. Roofing goes on top of that (picture 4). Picture 3 shows the panel lifted halfway up with the pivoting support leg at an angle.
Step 4: Enclosing the Cabin
Once framing was done it was time to add the shell. I used 1/2" plywood for the floor, roof and walls. The amount of plywood needed will be the combined square footage of the floor, front and back, one full side of the roof and lastly the non-opening side's upper roof. Remember that you have some overhang for the roof edges. For me this totaled about twenty 4x8' sheets.
After the plywood is affixed you should have a rigid structure and other ropes and bracing can be removed. I used tar paper to cover the plywood but Tyvek or similar products could be used instead. For roofing there are many options. I chose Ondura because of the more natural colors and it has a smaller panel that is easier to carry up hill to my site. Otherwise I could have used metal or Tuftex. Since this is a simple cabin and only has plywood keep in mind the attaching plan for what ever material you use. This could mean you need to set up the framing stage to match distances required for your roofing. For this reason I wouldn't suggest standard shingles since you would need lots more 2x4s under the plywood, if not you will have a wall of sharp nails poking through.
When you are ready to attach the roofing panels transfer the position of your frame elements out to the edge of the roof sheeting. Repeat for each side then snap a chalk line across. Start from one edge and you'll have to get the first screw or nail set based on the edge mark. I put a 2x4 between the ladder and the panels when starting on the second row and the top row so it wouldn't press into the Ondura. Use a regular saw to cut off any excess roofing.
The door and window frame in like they would in any other building. Since I was using a thin metal window frame I saved a bit of space on the inside by using the framing lumber flat against the wall.
For the front and back walls I got 1/2" planks from a nearby cedar mill, their B grade was cheaper and since you will do a lot of angle cuts and have small pieces for the top area it's easy to cut out the imperfections. Lastly on the back side a gutter was installed.
Step 5: Interior
Its your cabin so personalize it however you like. You can fully frame the interior and insulate it, add electricity and water if you have it available, a disco ball and shag carpet too!
We extended the horizontal brace to make a 12" shelf (picture 1) and adding some hooks to an upper frame member suited most of my needs. I set two of the framing members at about 6'5" above the floor on each side so I have a good sized shelf for storage on one end and used rope on the other end to hold a double air-mattress up out in the peak when not in use.
For large items like hanging a backpack I used a paddle bit and installed 7/8" wooden pegs. For the hammocks I used eye bolts (lag screw style) that could be installed horizontally and support a large adult in a hammock. Pegs and hook shown in picture 2. With the walls being 10' apart it was perfect distance for a light weight double hammock. One hammock on each side of the door seems to work well and leave room to get around at night. In theory you could probably get two hammocks on each side if you made it a little taller.
Lastly a hinged table was installed under the window its supported by chains when up (Pictures 3 & 4).
Step 6: Final Touches
To complete the cabin I cut down another pallet to make an awning over the door and another for the window. Using 6" Timberlok screws from the inside I mounted them and covered it with left over roofing (picture 1)
After the siding was on it left an unfinished look to the edge of the wall when the panel is up so I used aluminum flashing to form an inverted gutter-like cover and it covers the zig-zag siding gaps (picture 2). Stick on foam window seal is applied to the clean metal edge and forms a bug and weather barrier when the panel is down. Another strip can go on the underside of the panel for better sealing.
The panel is roughly 8x10' and doesn't weigh too much for an adult but you'll notice at the top of picture 3 I've added a gas strut on each side of the opening. Key was finding a pair that support 150 lbs each since the attachment point means they are supporting a large cantilevered object. With careful measurement they work well as you have probably seen in the video they can even support the whole panel without the fold out legs. For only $50 they are a bargain! It is not recommended to use them without the leg as they do weaken over time but it is a great assist in raising and lowering a wide panel like this.
I hope this inspires more cabins and please share your results and ideas. You can find a few more pictures at my build blog http://palletbuilding.blogspot.com thanks for checking it out.
Now you're done so clip in your hammocks, grab a book and chill!
Step 7: Equipment Needed:
- clamps (at least two decent bar clamps would be handy, more would be best)
- ~50' of rope
- paddle bit (3/4" matching the diameter of the hinge pipe)
- carpenter levels (4' or bigger for the floor and framing and 1' for some of the tight spaces)
- angle finder
- 12' or taller ladder (consider two ladders if you have them)
- leatherman (you always have this on you anyway, right)
- chalk line
- plumb bob
- circular saw
- drill bits
- generator (optional)
* when building with triangles, such as an A-Frame, the speedsquare can be your best friend. Learn to use the speed square at ( https://www.youtube.com/watch?v=BBJHQNR05xo pay close attention to the part at 2:00 and 4:20 )
Step 8: Finished Snapshots
Here are a couple of views from inside looking out, a bit of panorama and then what it looks like inside. The fish-eye effect makes some things look weird, I promise the piers are not leaning in real life. The last photo shows how much room there is for storage. A few cedar planks to the rafter make good shelves. Also I've been using a rope strung across the opening to hold a double air mattress up there. It could hold a lot more.
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