In this post, we provide information about how we selected a greenhouse design, the techniques we used to build it and generally provide an overview of the process.
While we’ve built plenty of things, it was an adventure to create our own building from beginning to end! We aren’t professional builders here. In fact, we’ve never built a structure entirely on our own before!
Finding Plans For The Greenhouse
It was probably within our skill set to design our own greenhouse. We aren’t architects, but we do understand the basics of framing and general construction. Greenhouses aren’t usually complicated structures, unless you really go all out.
However, when you have a set of plans, the overall process is much easier. It saves you many hours of having to come up with a design, putting together material lists and creating cut lists. Using a proven design also ensures that your structure will stand the test of time.
The Perfect Set of Plans! For Free!
It’s even better when you can find a set of quality plans for free!
As we searched for options out there, we kept coming back to a design from Ana White. Ana is a fellow Interior Alaskan blogger that publishes a great number of various plans for woodworking projects. She just so happened to put a fairly popular greenhouse plan out there, a lovely gambrel style greenhouse.
This greenhouse has certainly “seen the rounds” in the blogging and vlogging circles! It’s been crafted by Ana, Wranglerstar, Justin Rhodes, Homegrown Homestead and dozens of others that submit “brag posts” to Ana’s site. We can now add the Frosty Garden Homestead to that list!
We have seen these gambrel style greenhouses all over Interior Alaska. It’s a very popular style here and is tried and true at handling our winter clad environment. We really liked the design too, so that was that!
Improving On The Ana White Greenhouse
We didn’t want the cheapest greenhouse. We wanted a good greenhouse that we’d be proud of and would last for many years. Frosty Garden quality, if it were a thing.
Ana’s plans get a lot of things right. Really right. The plans are incredibly efficient with regard to lumber. For where we live, the steel roofing used as siding will provide ample protection against the several feet of snow we get every year. The gambrel style is a very solid building style for heavy snow loads. It can easily handle 50 PSI of snow like we get in the Interior of Alaska, which means you don’t (usually) have to worry about removing snow from the structure throughout the winter.
As we reviewed the plans, however, there were a few things that we knew we wanted to improve upon. You do have to keep in mind that with free plans, you might want to put a little work into them to adapt them to your situation, experience and means.
In our view and experience, the plans were missing a few critical components:
- Structure needs a proper ridge cap
- Structure needs some flashing to protect from rain
- Lumber should be protected against the environment
- Inadequate ground protection from wild plants and grasses
- Appropriate foundation
- Structural grade lumber ties
- Kreg screws are great for tables, doors and DIY projects. Nails provide shear strength that will stand the test of time when it comes to a building
- Automated ventilation
- No door plans
This list essentially boils down to three major categories of concern:
- Protection from the environment & surroundings
- Structural protection
- Controlled growing environment (which is the most fundamental point of having a greenhouse to begin with.)
Picking The Must-Have Improvements
To me, it just didn’t make sense to put $1,500+ into a structure and not give it a chance to stand the test of time.
In general, we weren’t willing to negotiate in matters of reasonable protection against the environment. Doing most everything we could to protect the structure from above and below were top of mind. A “decent enough” foundation was on our essential list. Appropriate flashing & lumber protection was also non-negotiable.
We opted against a frost proof foundation, even though that’s what would be advised for virtually any structure in our subarctic environment. While we view this as a structure we want to last, it’s also not permanent and we might want the option to move it in the future.
We are also familiar with our experiments in small, cheap greenhouses. Proper, temperature controlled ventilation is an absolute requirement for a greenhouse. The whole point of building a greenhouse is to control the environment, typically with the goal of achieving higher than ambient air temperatures for as long as possible.
Another technical decision we made was to use tie plates instead of custom manufactured plywood gussets. Nailed tie plates are really easy to work with and are well worth the money you put into them. For us, we could spend $50 on a sheet of plywood or $75 on structural grade, steel fasteners. It would save several hours of construction time and also makes the rafters much easier to assemble.
We did consider extending the size of the greenhouse from 10×12 to 10×16. This is a fairly simple modification to these plans. After much deliberation, we decided to stick with the original size. Our decision was fully reaffirmed upon building the foundation!
Matters Of Building Code, Setbacks, Covenants and Property
We are fortunate to live in an area where we are not subject to building codes. That said, we want to build structures that are relatively up to code and can actually add value to our property.
When you’re in a situation like us without stringent building codes, it does ease things a bit. We didn’t have to pull a permit to do this, nor did we have to meet some strict code enforcement to put up the building. Your situation might be different.
We were placing this greenhouse near to one of our property lines. It’s always important to check setback requirements when you do something like this. Building codes or not, setbacks from your property line for structures are practically universal wherever you live.
We also have some covenants we have to live with. One of them is basically that an effort must be made to make outbuildings similar in appearance to the primary home on the property. No one on the block actually follows this covenant in regard to their outbuildings, but we thought it was a good idea as we really like the look of our home.
Technically this isn’t a permanent structure. It could be removed in a day. But, our barn also doesn’t meet permanent structure requirements, either, and it shows up on our property plat. So we wanted to make sure everything was reasonably legit, just in case that happens again.
Major Considerations For The Greenhouse Location
While Ana states on her blog that her greenhouse has lasted many years without a foundation, that wasn’t how we wanted to roll. We considered a number of different techniques for the foundation.
In the subarctic, if you want to build a permanent building, a frost proof foundation is absolutely necessary. The thing is, we didn’t really want this structure to be permanent at this time, we might want to move it. So, that meant we could get away with a cheaper, less permanent foundation for now.
The first consideration was the location. Structurally, it couldn’t be somewhere where we get a lot of water and ice, since this contributes to the earth shifting (frost heaves) in the spring here. We picked one of the drier spots on our property and one that doesn’t seem to shift significantly over time.
The second was how the structure could potentially fit in to our rough “master plan” for our property. In our “master plan” we have a large, 40×60 garden, fenced in with 12 foot fences, where a greenhouse or two might be. In our chosen location, the structure could stay where it is, or be moved later.
Of course, we considered the sunlight. Our property gets fairly good coverage from the sun in all our cleared areas. We were fortunate to have a number of options in this regard. But, we did pick a location that receives great sun from mid morning all the way up to the evening sun.
A minor consideration was reasonable access to water. The intention for this greenhouse is for it to be totally off the water grid. While we have installed irrigation and rain water catchment systems, a future owner might just prefer to use the house spigot and a hose.
Building A Foundation For The Ana White Greenhouse
The nice and sunny spot we picked out wasn’t perfectly level. A foundation would help us level the structure a bit and also ensure that it is fully secure from winds and whatever else mother nature might throw at us.
Surveying The Location
We started with a basic survey and orientation. We marked a known position where we wanted one of the building corners to be. From there, we measured out the rough dimensions of our planned foundation. We checked the points for square. This gave us a rough idea of where we’d need to dig.
Starting The Foundation Excavation
Our selected location wasn’t perfectly level. We’d have to do a little bit of digging to ensure we could start with a relatively level foundation.
Digging out the foundation was a lot of back breaking, hard work. A lot of quality time with a pickaxe, shovels and a wheelbarrow. It didn’t take us long to realize why Ana might have skipped this part. It’s by far the hardest part of the whole process.
Laying In The Foundation
We opted to use 12 foot 4×6 pressure treated lumbers as our foundation.
These would be secured into the ground with 1/2 inch by 2 foot rebar, driven through the foundation lumber and into the ground. This will help with resisting movement in the spring when the ground tends to shift due to thaws here in the Interior of Alaska. It’s not frost proof, but perhaps frost resistant.
After we were pretty close with our digging, we cut two of the timbers to the building’s shorter dimensions. The 12 foot lengths were perfect for the long dimension. This allowed us to better eyeball our lines and get a bit closer to level.
Our general goal was to get “close enough” to level. 80% of the bubble on a level was good enough in our work. We did our best to determine it square and at the right elevation, but we didn’t strive for absolute perfection. The plants honestly aren’t going to care one bit and this isn’t a habitable structure.
We were building this greenhouse in an area where we have some grass. I didn’t want to manage the grass or weeds near or in the greenhouse. So we made sure to install weed fabric under our foundation before we secured it with rebar.
Clearing Out The Sod For The Greenhouse Floor
From this point, we decided after we laid in the foundation that it was necessary to remove the sod inside the greenhouse. We had originally hoped to just level in and put a couple layers of weed fabric over it. Once the foundation was set, however, the inside ground was higher than the foundation. That’s not good, so we removed the sod from inside the greenhouse.
At this point, we were all set to get started with building the structure!
Framing Ana White’s Gambrel Greenhouse
It would be a lie to say we weren’t slightly concerned about constructing the gambrel style as our first self-built building. It’s a challenging structure, especially for a first time builder. It turned out easier than expected, but it definitely gave us a work out of our skills.
Framing The Greenhouse Walls
The walls of the building were fairly simple to construct. It was fairly quick work with a pneumatic nailer, but using a hammer would have been fine too. The door end was a bit more challenging, but also not that bad. We had these completed by late morning on our first day of framing.
Framing The Gambrel Building Ends
From there, the next step was to assemble the two ends of the structure. Our general strategy was to do the lumber cuts and then assemble them close to what they would look like fully assembled.
This is also when the nail plates came in extremely handy. Using nail plates meant we didn’t have to spend hours making plywood gussets. The cost between the two is not all that different, unless you have plywood just lying around.
We hammered in some 1.5″ 8D structural nails into the tie plates and called it a day. We used the nail tie plates on both sides of each joint. The rafters and ends were quite solid afterwards.
From there, it was fairly quick to go up. We toe nailed the ends in place and used a few 90 degree Simpson ties in the back to offer a little more stability. We knew that these didn’t have to have perfect stability. Once the greenhouse panels are installed, the structure would tighten right up.
This was the end of day one!
Framing The Greenhouse Rafters
Step one was to hang the ridge pole. This was challenging with both of us on a ladder. We butt nailed the rafters in place once we got them to a position we were happy with. Then, we further secured the ridge pole with 2×4 joist hangers. We were able to nail the 8D nails through the nail plates without difficulty.
From there, the rafters went quite quickly. Again, we used nail tie plates to assemble them. We attached them to the structure with toe nailing and some additional 90 degree Simpson brackets. This offers a little bit more peace of mind for us when it comes to snow load, although this probably wasn’t necessary. The gambrel design does a great job at distributing load to the ground.
We modified the plans a bit to account for our ventilation systems. We ordered pairs of fans and louvered vents for this purpose. It was a fairly simple task to get the measurements and figure out the angles needed. Everything in the plans are either 22.5, 45 or 90 degrees.
At this point, we decided that we would go ahead with staining the lumber. We gave the building a quick sanding to remove the lumber labeling. While we could have stained it by hand, we were quite happy to break out the Graco paint sprayer and we were able to get the job done in a couple of hours. We had a rather unseasonable wind storm occur right when we did this, so that was kind of annoying. This brought us to the end of day two and also ended the framing work.
Though this step wasn’t entirely necessary, it really makes the greenhouse pop. We are fully glad that we decided to do this step. It was worth every bit of time and money.
Siding The Ana White Greenhouse
The original plans do gloss over this part a bit, you’re basically on your own for siding.
Installing The Steel Panels As Greenhouse Walls
The steel roofing material we used was a little bit larger than what Ana used in her plans. Our material was 39 inches wide, which we quickly learned we’d have to trim to get it to fit the 35 inch walls. While we did consider raising our wall height to match the material we had, this would have severely increased lumber requirements.
We weren’t about to spend the time and energy to do this cutting with tin snips. We broke out the table saw and ripped the panels to size.
This really sucked. Not only because we sacrificed a blade but also we were showered by sharp and hot metal shavings. Definitely a job that requires eye protection.
The trim we decided to use wasn’t really intended for the purpose. We went with 1.5″ drip edge to save a bit of money. The slightly darker brown contrast turned out quite nice in our opinion, so we were happy with the decision.
Installing The Greenhouse Panels
From there, it was time to make it look like a greenhouse!
We spent a bit of time thinking about our strategy of how to put the panels up. Accessing the top is less than ideal from the ground. Easily done, however, from inside the building with a ladder. We used a bit of bottom up and top down techniques.
These panels weren’t that bad to install. It was nice to be able to knock it out entire sheets. Also, once these were installed, the building really tightened up. There was virtually no lateral movement. All the rafters and gambrel ends were working together to secure the structure.
In hindsight, we would have done things a little differently. See the section on what we learned for how we’d go about this.
Installing The Greenhouse End Panels
The ends were a little bit more tricky to panel. For us, we made this even more complicated with several designed openings.
The technique we used was to take our longest measurement for a panel and cut the 12 foot panels to that length. Then, we placed the panel on the end and marked the corners and general cut marks. We then used a straight edge to draw lines between those points. We used tin snips to trim the panel.
Not fun work, but Kayde was really good at it! We did have to make a few adjustments here and there. Just remember, it’s easier to cut off more material than it is to add it back on.
The Greenhouse Ventilation System
A greenhouse is a double edged sword. While it works great at producing warm air temperatures on moderately cooler days. The greenhouse can also create plant killing temperatures on a hot day if you don’t have some way to ventilate it.
We aren’t the type of people that have the freedom to just open windows or vents when the time is right. We wanted our greenhouse to be relatively automatic so that we can maintain an optimal temperature, regardless of what’s going on in our lives. That meant using our favorite Inkbird temperature controller and a ventilation system.
Calculating A Greenhouse Ventilation’s Needs
We calculated that our greenhouse was going to need about 1,600 cubic feet per minute to fully replace the air once per minute. We wanted to shoot for a little higher than that, about 2,400 cubic feet per minute, just to be safe.
This fan calculation also determined the size of our louvers. To allow for proper intake at 2,400 cubic feet per minute, we would need about a 32 inch opening. We decided to go with two 16 inch openings.
I was able to find suitable fans and louvers on Amazon. I don’t know how Amazon makes money on shipping 40 pound fans up here, but I feel like I got my money’s worth. The air entry louvers are kind of light duty, but they appear suitable for the job. The fans seem fairly well built, but I was disappointed that no hardware mounting or electrical cord was included.
You’ll notice that there are two fans. This, for us, was both a technical necessity and just a good general practice. We went with two slightly undersized fans. We could have also gotten away with one, larger fan. While it was more costly, it ensured the higher end of recommended ventilation and also allows for a bit of redundancy. We can lose one entire fan and still not risk losing our crops to excessive temperatures.
We received confirmation that our ventilation was done right once we built the door. Once we did this, our fans produced enough negative pressure to activate the louvers. This was a great step forward! We knew that we’d be pulling fresh air from where we wanted through the greenhouse.
Building A Basic Door For The Ana White Greenhouse
We decided to build our own door as opposed to buying one. It was both less expensive and we would have had to custom order a door to the opening’s dimensions.
This is the one place in the entire build where we actually used a Kreg jig and pocket hole screws. We didn’t agree with Ana’s original design using pocket hole screws to assemble the entire building. For a door, though? Perfect!
The door we designed was a fairly simple rectangle with a couple of cross braces. We tossed a trimmed 8 foot greenhouse panel over the top and called it a day. We finished it off with a latch and a handle on either side of the door. It’s quite sturdy and will do the job nicely.
We opted to install the door so it opened inside of the greenhouse. While this does take up some vital inside floor space, it was for a very important reason. An inside opening door allows us to access the greenhouse in winter, if needed. We won’t have to spend any time shoveling the entrance should we need to get in there.
We determined that we needed an inside latch as well after we built the door. The fans have a tendency to pull the door open. A small latch allows us to secure the door when we are inside the greenhouse and the fans kick on.
What We Learned Building Ana’s Greenhouse?
I think if we were going through this process again, there’s a few things we would have done differently.
Consider A Tractor For Dirt Work
We would strongly consider renting a Kubota to do the hard dirt work. It’s painful and time intensive work to pickaxe your way through sod and rocky soils. We spent a solid 36 hours between the two of us hacking it in. With a tractor, we could have done a better job at leveling the entire area and probably would have used it for a few other projects around the homestead. That would have also increased the cost to build by several hundred dollars.
A Better Way To Do The Roof Panels
An ideal solution to the plans would have been the addition of two more 12 foot greenhouse panels. Ana’s original plans specified 12 panels will fit the greenhouse perfectly, with very little waste. We would have preferred to use 14 panels, or 10 to cover the roof. This would have allowed one panel to act as a ridge cap instead of the custom one we had to manufacture. It also would have left material over for a custom made door, a material which we had to buy after the fact. This would have increased the cost by about $70.
Install The Greenhouse Panels Vertically
We understand why Ana has the greenhouse panels installed horizontally. It provides structure, is easier on materials and is much easier to install. That said, it is less than ideal for water removal and it created a number of other issues for us. We only saved about $100 in materials such as ridge caps and extra panels. When we eventually replace the panels due to age, we’ll reinstall them vertically. This requires horizontal support beams (lap boards) to be installed for structural rigidity.
Closure Strips Suck
We also learned that we really don’t care for closure strips. We bought them, put them on and then decided to tear them out. They are poorly manufactured, require pre-drilling to prevent splitting, make trim more difficult and in general, make the siding job harder! Most importantly, they negatively impact the rain handling of the panels when the panels are installed horizontally like this.
We have observed that they make (presumably) better ones now out of plastic, but they are not stocked in our area. We could have saved about $30 if we didn’t even mess with them.
The Plans As-Designed Are Incredibly Lumber Efficient
We were very pleased with how efficient the plans were. We did have to make a number of cuts “right on the line” (or, split the kerf) as they used exactly the lumber’s dimensions. This did result in a few imperfections, but we wouldn’t have changed anything.
This was the scrap remaining from our entire build. Incredible!
Additional Materials Were Needed
As for extra material runs? The specified 12 panels will not provide enough scrap for the greenhouse door, if you want a similar look to ours. We also originally bought about 10 extra 2×4’s for various other reasons (door, extra framing, door threshhold, etc.), but the plans as given are incredibly lumber efficient. All in all, this increased costs by about $50.
Notes On The Ana White Greenhouse Performance
One item that was interesting to us on this greenhouse design was how it would perform. Ana’s page didn’t really talk about how well it worked.
We didn’t really take any care to “seal” this greenhouse. We didn’t use closure strips, either. There are many areas where air can exchange with the outdoors.
In general, on a cloudy day, it has no problem holding 10-20 degrees above ambient air temperatures. For us, this usually results in about 65 to 75 degree temperatures.
When it’s really sunny out, it can definitely get quite hot, quite quickly. Our fans will kick on every few minutes for about 15-30 seconds, depending on how warm it is outside. Ventilation is vital in any greenhouse!
We have our ventilation system set to maintain between 80-85 degrees. The fans will kick on 85 and turn off at 85. On most days with direct sunlight, the ventilation system kicks on many times throughout the day. On a warm day, the fans will kick on very regularly.
In the future, we might consider lining the inside of the greenhouse with greenhouse grade plastic. We have found the greenhouse doesn’t maintain heat super well, so cool evenings (especially when it gets below 50F) can be less than ideal. This will provide two layers of protection and will also ensure our air intakes are used more optimally.
Our Costs To Build The Ana White Greenhouse
A popular question is always going to be, “how much did it cost?” We’ll lay it out there in Interior Alaska prices. This doesn’t include anything related to our growing systems that we use in the greenhouse to grow food.
- Lumber & most building materials (Home depot): $1600
- Ventilation and temperature control (Amazon): $325
- Electrical (Home Depot & Costco): $100
- Weed Fabric: $100
- U-Haul Rental To Deliver Materials: $65
With regard to the weed fabric, we ordered two rolls of 5 ounce fabric at 250×5 foot lengths. We had plenty to use on this project, but our intention for the purchase was to use the remaining fabric on our community garden. The cost is reflected if you want to build like we did.
Approximate Cost: $2,300
In time, we had to put a lot of effort into it. Between the two of us, this is about where we’re at for man hours on the project:
- Foundation work: 36 hours
- Framing Work: 40 hours
- Siding, Paneling & Trim: 32 hours
- Electric & Ventilation: 2 hours
Total Time: 110 hours
The whole process took about 10 total days for us to do, some of which were partial days after work and such. We were skunked by rain one weekend day, so that put us behind schedule a bit.
There are always people that will say, “Why didn’t you do this, or that?” The biggest one people might ask is why we didn’t pursue passive solar. For us, the bottom line was the extension of another two weeks on either side of the season really wasn’t going to buy us much. Our winters are brutal and unforgiving. We want to be inside and not gardening when it’s cold out.
We know we didn’t cover the actual growing systems of the greenhouse in this post. Our initial growing system will be using our sub-irrigated buckets in here with one minor difference. Our goal is to centrally irrigate the buckets to make late season watering an easier task. We will cover this in a bit more depth later!
We had a lot of fun building this greenhouse and we are really pleased with how it turned out. It should provide many years of service for our gardens and will help us produce a lot of food.
If we missed anything that you are dying to know, put a comment down below!