Free step by step plans to build a barn style greenhouse!
About Project
Author Notes:
I have been dying to show you my Mother’s Day present.
For years and years and years, I’ve been wanting a greenhouse. Up here in Alaska, the only way you are going to eat cucumbers or tomatoes off the vine is to grow a greenhouse. Or steal from your Mom’s greenhouse.
But every year, every spring, we just have so much going on, the greenhouse never happens.
Next year, we say.
I thought next year would never come.
We were already saying next year this year.
So I tried something different
I said, what about tonight?
We started cutting boards at 4PM that night.
By that evening we had completed all of the wall framing.
I was so excited couldn’t stop myself from sharing a pic via instagram and twitter!
Jaime from That’s My Letter also sent me a work apron that is just so beautiful I was afraid to use it!
That first night, we actually called it an early night!
The next morning, we got up and assembled the panels in the driveway.
We used roofing tin for the side panels.
It’s relatively inexpensive and easy to install and will last much longer than plywood.
And I just liked the look of it too.
I designed the plan so each side uses uncut 12 foot long panels to save time and minimize scrap waste.
The corners are trimmed in simple metal flashing.
For the greenhouse panels, we used the ribbing strips, but they aren’t
entirely necessary. We started the ribbing strips so that the corrugated
panels would come up just perfect to …..
Wrap the top rib of the corrugated roofing!
It was a happy accident for us, but I hope if you build you will
consider wrapping the corrugated plastic over the roofing -
makes for a good seal!
All of the panels are predrilled
To prevent screws from splitting the plastic panels and wood.
We were surprised at how many screws we ended up using!!!
We used metal roofing screws.
Up to this point, we have not had to cut any panels! The sides of
this greenhouse plan are made a perfect 12 feet long so you can just buy
12 feet long panels and slap them up! Of course, the greenhouse is also
designed to use the widths of the panels, so no ripping panels down.
But on the gambrel ends, we will need to cut the panels to match the roof line.
We simply held the panels up in place and marked the cuts with a pen.
Then we used a chalkline to make perfect straight lines across ribs and cut with
a circular saw as directed by the manufacturer.
Grandpa Tim helped us out with this project.
We are very grateful for all his help and expertise.
The ends panels are screwed up without the ribbing strips.
We’ll be adding the flashing up to the outside corners as well.
And after years and years of waiting, within a matter of a few days,
working on the greenhouse here and there, we had this!!!!
We choose the gambrel or barn style roof design because you can get more
headroom inside while still having lots of room up top for greenhouse panels.
We love it.
And I wanted to get the plans out to you as soon as possible so you can also build it! Enjoy the plans!
Dimensions
Dimensions are shown above.
Materials and Tools
Shopping List:
Materials for 32″ stud walls -
3 – 2×4 @ 10 feet long – use on back wall
5 – 2×4 @ 12 feet long – use on sides/ridgepole DO NOT CUT)
32 – 2×4 @ 8 feet long
11 – 12 foot long x 26″ wide standard corrugated plastic greenhouse panels
1 – 8 foot long x 26″ wide standard corrugated plastic greenhouse panel (use on door side)
3 – 12 foot long tin panels (use on sides and back)
1 – 8 foot long tin panel (use on front)
Tin screws
28 – 4′ long ribbing strips
L flashing (optional for the corners)
You’ll need either metal gussets for the trusses or to cut plywood ones from 1/2″ plywood. We used scrap plywood from the Momplex need about 1/2 a sheet.
- Will make door in later plan
3 inch screws
wood glue
Tools:
measuring tape
square
pencil
hammer
safety glasses
hearing protection
drill
circular saw
compound miter saw
level
countersink drill bit
Cut List
Cut List:
Cut list is in plan at each step
General Instructions
Please read through the entire plan and all comments before beginning this project. It is also advisable to review the Getting Started Section. Take all necessary precautions to build safely and smartly. Work on a clean level surface, free of imperfections or debris. Always use straight boards. Check for square after each step. Always predrill holes before attaching with screws. Use glue with finish nails for a stronger hold. Wipe excess glue off bare wood for stained projects, as dried glue will not take stain. Be safe, have fun, and ask for help if you need it. Good luck!
Step 1
2 – 2×4 @ 118 3/8”
6 – 2X4 @ 32”
NOTE: I made the studs 32″ long to conserve 2×4 boards. But this meant we had to rip our tin sheets down about 3″ because our overall side wall height ended up being 35″ and the tin was 38″ wide. You can alter the studs to avoid this problem or even make the studs 45″ tall if you choose to use 1/2 sheets of exterior plywood creating 48″ tall walls for a taller greenhouse.
We framed everything up with nails and a nail gun and glue. You can also use 3″ exterior screws.
Step 2
4 – 2X4 @ 144”
14 – 2X4 @ 32”
Same is true again of the stud lengths.
Step 3
4 – 2X4 @ 32”
4 – 2X4 @ 42 ½”
2 – 2X4 @ 81 ½”
1 – 2X4 @ 33 3/8”
Note: If you later the stud length, you will need to then alter the door framing studs to the exact difference.
Step 4
We actually put the tin on the side panels first to save some time and work. The panels are just screwed together as shown here.
Step 5
4 – 2X4 @ 48” (BOTH ENDS CUT AT 22 ½ DEGREES, ENDS NOT PARALLEL)
2 – 2X4 @ 39 5/8” (LONGEST POINT MEASUREMENT, ONE END CUT AT 22 ½ DEGREES OFF SQUARE)
2 – 2X4 @ 48 1/2” (LONGEST POINT MEASUREMENT, ONE END CUT AT 22 ½ DEGREES OFF SQUARE)
2 – 2X4 @ 42 1/4” (LONGEST POINT MEASUREMENT, ONE END CUT AT 22 ½ DEGREES OFF SQUARE)
2 – 2X4 @ 7 3/8” (TOP CUT TO DOGEARED POINT MEASUREMENT, TOP END CUT AT 22 ½ DEGREES OFF SQUARE)
We layed the truss out on the garage floor and everything worked out perfectly. We used scrap 1/2″ plywood to create gussets but you can also buy metal gussets for the joints. Gussets are simply plywood pieces cut to cover joints and then screwed on with glue. We use 3-4 screws per board covered by the gusset per gusset, with normally gussets on each side of the joint.
Since we knew the end trusses would get the panels applied, we opted to only put gussets on the insides.
We attached the front truss to front wall with screws through undersides.
Step 6
4 – 2X4 @ 48” (BOTH ENDS CUT AT 22 ½ DEGREES, ENDS NOT PARALLEL)
1 – 2X4 @ 117 7/8” (BOTH ENDS CUT AT 22 1/2″ DEGREES, ENDS NOT PARALLEL)
1 – 2X4 @ 55 3/8 (TOP CUT TO DOGEARED POINT, 22 ½ DEGREES)
2 – 2X4 @ 55 ¼” (TOP CUT TO DOGREARED POINT, BOTTOM CUT 45 DEGREES OFF SQUARE, END CLIPPED)
The back truss is built same as front. See next step for close up of the center cuts …
Step 7
This board was a little tricky to cut – practice first!
Step 8
1 – 2X4 @ 141”
NOTE: If you use gussets – we used 1/2″ plywood – this will affect your ridgepole length.
TIP: I learned this from the Ram. Take your ridgepole BEFORE attaching to trusses and set it on the side wall. Then just mark all of the side wall stud locations on the ridgepole. Do this on both sides of the ridgepole. Then screw the ridgepole up in place. It will be marked now for the common rafters!
The ridgepole actually sits down from the end truss peak about 1/4″. This is shown in the diagram as well.
Step 9
10 2X4 @ 48” (BOTH ENDS CUT AT 22 ½ DEGREES ENDS NOT
PARALLEL)
10 2X4 @ 47 1/4” (BOTH ENDS CUT AT 22 ½ DEGREES ENDS NOT
PARALLEL) – shorter rafters go up to meet the ridgepole. I marked all shorter rafters to avoid confusion.
For the common rafters of this barn style greenhouse, we ended up using plywood gussets to save money. After cutting quite a few, I figured out how to cut gussets the super quick and easy way – got gusset cutting down to less than a minute each.
Going to apologize for the poor video – just wanted to show you quickly how to save some time and didn’t have time to call hair and makeup had a greenhouse to build!
We put gussets on both sides of each rafter joint with glue and screws. We made all of the small trusses first on the ground, then it was just a matter of stacking them on the ridgepole and attaching to the studs. We used 8 screws per gusset.
Common rafters are installed flush to top of ridgepole and flush to outside of side walls. We had to “toenail” the screws in – meaning they are screwed in at an angle. We used glue and 3″ screws from both sides.
Step 10
The plan will get you through the framing. At this point, you could use plastic paper, lexan glass panels, you name it to seal the frame in. We used the corrugated plastic panels detailed earlier for installation.
IMPORTANT: If you do not use panels you will need some sort of lateral support to keep the greenhouse from swaying side to side. Try 12 foot long 2x4s.
Good luck! We’ll be building the door in the next few days and adding plans as well.
Finishing Instructions
Preparation Instructions:
Fill all holes with wood filler and let dry. Apply additional coats of wood filler as needed. When wood filler is completely dry, sand the project in the direction of the wood grain with 120 grit sandpaper. Vacuum sanded project to remove sanding residue. Remove all sanding residue on work surfaces as well. Wipe project clean with damp cloth. It is always recommended to apply a test coat on a hidden area or scrap piece to ensure color evenness and adhesion. Use primer or wood conditioner as needed.
By Ana White