How to Build a 12x20 Cabin on a Budget




Introduction: How to Build a 12x20 Cabin on a Budget

About: Just a normal guy trying to make it in life .Good paying job but mindless sometimes .I enjoy making things in my garage to keep my mind going .. Its fun making something new but its more fun taking something…

Building a cabin yourself is much more economical than buying a prefab storage shed. The cost of materials for this build, including doors and windows, was around $2,200, which was about the same price as the install would have been on one of this large size if I’d purchased it from a hardware store. I know this for a fact because six years ago I bought a 12x16 shed from a well-known company close to where I live and it cost $2,000 for them to build it and drop it off. Today that same building would cost $4,200. With such a big price increase I decided that if I wanted to add a cabin to my property I had to build it myself.

If you decide to do the same, remember to check with your local authorities to make sure you don’t need a permit. It’s not likely that it’s required for a building of this size, but you never know.

If you would like to see the finished inside of the cabin please click here:

If you would like to see the matching modern outhouse please check this out:

Step 1: Floor Illustration

Here is the 12x20 floor plan showing where the 4x4s and the floor joists would be located.

Step 2: Drilling and Planting the Posts

1st picture: shows my ford tractor and my neighbors post hole digger he let me borrow.

2nd picture: shows the posts planted and the bottom 2x10 stringers.

3rd & 4th pictures: show the upper 2x10x12 and the 2x10x16 upper stringers being nailed in at 7 feet 8 inches.

Step 3: Setting the Center Rafter Board

This picture shows the center rafter board. I measured over 6 feet to the center. The roof is going to be a 5/12 pitch roof so the rafter board had to be 30 inches to the top of the board.

Step 4: Making the Angles for the Top and Bottom of the Rafters

1st picture: shows using a quick square. Put the pivot point at the top of the board and turn the square until the 5 on the * COMMON TOP CUT* line graph lines up with the outside of the board. Then draw the line to make the angle.

2nd picture: Once you cut your first angle then you have to measure from the tip of your cut down the length of the rafter to get your measurement for the seat cut. Once you have that measurement then you put the pivot point on that mark and turn the square until you get your 5/12 angle again. Then measure up that angle 2 1/2 inches and draw that line.

3rd picture: shows taking the edge of the square and lining it up with the 2 1/2 in line and turn the square until the tip is lined up with the edge of the board. Then draw that line.

4th picture: shows the angle seat that I just drew cut out.

Step 5: Setting the Rafters

1st picture: shows the rafters being set next.

2nd picture: shows the rafters on and the starting of the purlins being put on the top of the rafters for roof support. This is what the metal roofing is screwed to.

3rd picture: shows the tails all cut to 9 inches long and shows the steel roofing over hanging the roof by 2 inches to support the facia boards.

4th and 5th pictures: show the roofing installed.

Step 6: Adding on a 4 Foot Porch

Here is where it started to get complicated for me. I was looking for a 12x16 cabin, but once i looked at it I decided I wanted the whole 12x16 for floor space so i added a 4 foot porch to the 12x16 to make it a 12x20 total building instead of a 12x12 inside living space.

Step 7: Side Wall and Purlin Illustration

Step 8: Lag Bolting the Outer Joist to the 4x4 Poles

I had to screw (36) 3x3/8 inch lag bolts to all the outer joists into the 4x4s for stability.

Step 9: Hurricane Studs

1st picture: shows the (20) 13 inch hurricane studs with the 5/12 pitch angle cuts.

2nd picture: shows them installed.

Step 10: Floor Joists and Insulation and Floor

1st & 2nd pictures: show the (14) 2x10x12 floor joist installed

3rd & 4th pictures: show the 1x2 furring strips nailed to the inside of the floor joist 1 inch below the top of all the joists.

5th picture: shows the 1 inch insulation board between each joist before gluing and nailing the floor to the joist.

6th picture: shows my Dad lending a hand nailing down the floor.

Step 11: Rough Sawn Lumber for 8 Inch Board and Batten Siding

1st - 3rd pictures: show my dad cutting the siding boards to 8 foot long.

4th - 6th pictures: show the boards up on the wall and the soffit and the facia boards being put on.

Step 12: Studding in the Porch Ceiling

This picture shows the studding in for the porch ceiling, 16 inch centers and 4 foot long studs.

Step 13: Studding in the Front Wall and Door Frame

Studding in the front wall and front door frame, it was a hot day!! Here's my dooraggin' Dad! Just had to take a picture of this! He-he-he...

2nd picture: my friend Josh came over for a day to lend a hand on the mitre saw.

Step 14: Gable Ends

Here are the gable ends finished with the batten strips attached. All that's left for them are the two vents.

Step 15: Finished Cabin Structure

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    351 Discussions


    Tip 27 days ago on Introduction

    Your dimensions are wonky on the first diagram. If someone wasn't familiar with construction this could be pretty confusing... Total length & total width, at least, are incorrect. 🙂👍 Enjoyed the article, regardless. Thanks!


    Question 2 months ago on Introduction

    I’m new to Instructables and I don’t know how to search so I was wondering if there is a material list anywhere so I can get a good idea of what it would actually cost these days based on COVID-19 lumber pricing.


    Question 3 months ago

    Do those bolts you used to attach the outer joists to the posts have the tensile strength to support the weight of the entire building?


    Question 7 months ago on Introduction

    Is there some way to get a detailed materials list so I could order the ma\terials all at once


    11 months ago on Step 15

    I was a little surprised that so many were so critical of your building
    techniques. No, they are not to "government" standards, but they are
    fine in this instance based on the size of the structure. I will wager
    that the building will still be there when most posting here are dead
    and gone as long as you continue to do maintenance on it as required. I
    like it and it is a nice cabin.

    I am a licensed contractor, so I
    clearly understand building codes and safety, and I still see no issues
    with your shed/cabin. Building codes are different everywhere, and I
    actually built a small 20x20 cabin using almost similar techniques 25
    years ago when I was very young and had limited building skills at the

    My small cabin was in a rural county location where there
    were no building codes at the time, so I could do it however I wanted. I
    used 6x6 pressure treated posts (no concrete either), although I put
    them about 4 ft down on hard undisturbed soil with about an inch of
    gravel in the bottom of the hole, then packed them back with the dirt I
    dug out of them. To this day my 6x6 posts are still as solid as the day I
    buried them.

    My cabin is 8 ft off the ground due to flooding
    possibilities, so it sits almost 20 ft off the ground at the ridge
    points. I have done very little maintenance on it as well, since it was
    stained instead of painting. I haven't even had to stain it again. I
    used a good acrylic stain and it is amazing how well it has held up. I
    shingled the roof with 30 year 3-tab shingles and they look like they
    could last another 10+ years even today.

    My building is still
    standing today and we use it often. It looks exactly as it did the day I
    completed it really other than the trees around it are all much larger
    and I have improved the interior over the years. It hasn't sagged,
    settled, blown down or collapsed and the walls haven't pushed our or
    apart either. I have vaulted ceilings as well, and my construction was
    very similar. Looking back, if I could to do it over again, I would have
    placed my ledger boards for my floor joists directly on top of the 6x6
    posts, rather than bolting them to the 6x6s. That is clearly a better
    building technique that didn't seem that important at the time. I just
    didn't know any better. The key to my success and the longevity of me
    doing it that way is my ledgers and bolts are not exposed to the
    elements. There is always the concern of shearing, but after 25 years
    without any issues, I'm feeling pretty good about it. As low as his
    structure is to the ground, shearing isn't much of a worry. 8 ft off the
    ground is a different story.

    My siding over hangs my ledger
    boards, so they are out of the weather and the ledgers along with my
    bolts remains dry at all times. I inspect them from time to time and
    even considered making some changes to that part of the cabin once I
    learned better techniques, but my boards and bolts still look as clean
    and new as the day I bolted them in place. 25 years of solid service, so
    I have just left them as they are and believe it or not, it hasn't
    sagged or collapsed as some here claim it should.

    We get very
    little snow here, so snow weights on my roof are a non factor really. If
    you live some place where you get lots of snow, then by all means take
    that into consideration. Obviously if you have the money and materials,
    build it all to code. I'm not suggesting anyone build anything that is
    not safe, so do not take my post the wrong way. All I am saying is his
    building techniques might not be to government code, but they are good
    enough for his structure and I believe that his building will last as
    long as he does if maintained properly. Even the best built homes will
    deteriorate and collapse if not maintained over time.


    1 year ago on Step 15

    I was greatly disappointed that there weren't any instructions given/shown on window AND door installation. These would have been extremely helpful as would have Benin the instructions on how the loft over the porch was finished out.
    The roof framing was pretty well done until it came time to show how to prepare the roof for the tin/aluminum roofing panels.
    Thank you for the space to put this feedback in.
    Bill 🙂


    Question 2 years ago

    The building code here limits sheds to 10x10 before it needs a permit. What would i need to do to shrink it?


    Answer 2 years ago

    Ok ,this guy built something rather nice and shared it with all of us, so I get it about building codes, but lets just look at it for what it was intended, a simple share for someone that may want to creat this, again, nice project.


    Reply 1 year ago

    You obviously did not understand my comment. I was asking how it could be made to fit the constraints in which we live. I made NO comment about the project itself. It just doesn't work for my situation and I was trying to find a way to make it work. Next time, please READ the comment before you make one.


    Reply 1 year ago

    Just use your imagination and plan it on a smaller scale. Not really that hard...


    Question 1 year ago on Step 4

    Where's the material list, the length of the 4x4 posts for example


    Question 1 year ago on Step 9

    I can't find any information about "hurricane studs." Are they serving the same purpose as hurricane ties?


    Question 1 year ago

    Is there a complete bill of materials available?


    2 years ago on Step 2

    Do you have a list of all the wood you have used? Also I want to build a 12x2 without a porch. How do I adjust for that?


    Reply 1 year ago

    Just don't build a portch.


    1 year ago on Step 13

    What is the distance between the sides and the door?


    Question 2 years ago on Step 3

    I'm too lazy to search 342 discussions. I'd rather get a picture or at least more info how you secured the roof struts??


    8 years ago on Introduction

    Don't try building this in New Zealand! It does not comply with the Building Code and you also risk a substantial fine if it is constructed without a Building Consent.


    Reply 8 years ago on Introduction


    Building in New Zealand is governed by the Building Code and by NZS 3604:2011 (Timber-framed building standard.)

    This instructable infringes the NZ standard in so many ways that it would not pass initial scrutiny by a Local Authority if a Building Consent application was to be lodged.

    A few points -

    1) The joists are too close to the ground, are attached to the boundary "bearer" with nails in shear and have no approved metal hangers.
    2) Foundations can be either a concrete slab with footings and steel reinforcing to suit the site or piles (set in concrete) which support bearers which in turn support the joists. A "pole" building such as this does not comply.
    3) Wall framing must be by way of studs (size and spacing to NZS 3604) - a building of this sizs would need guaged 100mm x 50mm studs. Walings fixed to posts to support cladding is not acceptable for a habitable building. The entire floor, walls,roof and cladding on this instructable are supported by coach screws in shear.
    4) The rafters are not connected be either ceiling joists or collar ties to prevent the walls being forced apart under live roof loads.
    5) There are no moisture barriers in floor, walls or roof.
    6) There appears to be no head flashings to the joinery.
    7) Bracing, under the code, is inadequate for wind and earthquake.

    I do not suggest that the building causes danger to its occupants - just that the NZ viewer was thinking of building it in their yard and by doing so would cause much trouble for themselves.