Converting My Patio into a Greenhouse

…for less than $650!

I recently decided I’d had enough with my dank, dark, hot, inconvenient garage set up and took on the task of enclosing my patio… entirely on my own.

The bulk of this project took six days, after which I was just rearranging and completing all of the finishing touches. I’m going to break down the materials I used and how I built the frame, how I weather and water proofed the enclosure, and how I’m getting creative with space-saving ways to house my plants.

Keep in mind that I did not have to build or extend my roof in any way, which I imagine would have made this a bit more challenging. Essentially, all I’ve done is built a fourth wall.

Everything I used was purchased from Home Depot, with the exception of the window that I got from the Habitat for Humanity Home Store.

Day 1

The first day of the project, I got the lumber I would use to frame the outside of the wall and got started first with the part of the frame that would meet the concrete, then the top of the frame, which was screwed to the existing ceiling trim, and finally the studs (that run vertically along the wall).

I wasn’t sure what size window or door I would use just yet, so I didn’t completely frame that area the first day. I knew I wanted my window sill to sit 30″ above the floor so that I could use that sill as a working area. (28-30″ is average desk height.)

Starting with the part of the frame that meets the concrete (this is called a plate):
I used my chalk line to pop a line across the opening where my wall would be and used this line to place my treated 2x4s. I secured them with a generous bead of liquid nails and concrete screws. I then placed the concrete blocks on an area of my board that was slightly bowed, just to ensure that it adhered completely.

I realized that I must have measured the height of the wall incorrectly because I thought it was exactly 8 feet, however it was slightly more. Instead of exchanging my lumber for longer 2x4s, I decided to just build a top plate that would secure my studs, and then secure that header to the existing ceiling. Use star drive screws when framing so your screws will be less prone to stripping.

Day 2

Door day! After I spent way too much time looking for a used pair of french doors, I decided to go with a storm door instead. It fit within my budget and I like that I can lift the glass to increase airflow when the weather is nice.

As you can tell in this picture, the plate now extends further along the concrete. Since I was planning to use french doors, I had cut back my plate to account for that. Once I changed my mind, I simply extended the plate by adding another section of treated 2×4 the same way I installed the original plate.

When you frame a door, it is extremely important to leave about an inch of space on either side of the door. So, if your door is 36″ wide, you want your opening (the space between the studs) to be 38″. This allows your door to open and close properly as well as any expansion of the wood due to heat/moisture.

Next, I created a header above the door. It is important that your header is very strong because any sag will cause your door to not close properly. For this reason, you want to double up your 2x4s, rotate them to provide a thicker height, and sandwich a 1/2 piece of plywood inbetween them.

Day 3

I cut back the center of the frame I installed on Day 2 so the window could be supported by its own floor-to-ceiling stud. Then, I screwed the window onto the bottom and vertical 2x4s before finally installing a window header with the same method as the door header. When framing the window, be sure to leave about 1/2-3/4″ around the window itself to allow for the wood to expand in warm weather.

Day 4

On day four of this project, I started to worry about a few things… “What if it’s too humid inside, won’t the sheetrock develp mold?”, “What if I lose too much light after completing the siding?”

Then, I remembered I’m a genius and came up with solutions to both problems.

I decided not to finish out the interior of the wall so that I could use the space between the studs as shelving. I also chose greenhouse polycarbonate instead of siding to finish the outside of the wall.

This particular polycarbonate allows 65% of light to penetrate, making it the perfect choice for the way our house sits. We are on a hill where this room is very visible to the road and I’m not super into people being able to see my inspecting my plants in my pj’s, but I also didn’t want the wall to be completely opaque.

There are several choices when it comes to this material, Home Depot’s website does a good job of explaining the differences in opacity.

The shelving worked out very well because I was able to use scrap 2x4s that would have likely been discarded otherwise.

I used dowel rods to create a little more safety for pots that live on these shelves. I drilled holes into the studs that were the same diameter as the dowel and then slid the dowel into place by bending it slightly until both ends were in the studs.

I affixed foam weatherstrip tape to the studs to fill the spaces left where the corrugated polycarbonate meets the wood. I should have opted for thicker tape, though, because there was still some open space that I later filled with clear silicone.

It’s also really important to make sure you’re using the appropriate screws to affix your panels. These have a rubber washer that will create a seal when in place.

Day 5

It rained a ton on the fifth day, so I worked mostly on interior shelving and finishing affixing the polycarbonate panels.

Day 6

By the end of Day 6, I had installed my window sill, trimmed the outside of the window, caulked every space I could find, and moved plants in!

For the window sill, I used a 2x12x4 common board and I really love how this turned out. It gives me just enough space to work with cuttings and do some repotting.

I installed the majority of my shelving with zinc plated corner braces as brackets. I did this for budget reasons, but they serve their purpose well.

Be sure to screw your shelving brackets into studs.

I also screwed scrap 1x2s to the front of each shelf for added protection.

Budget:

Lumber: $164.56
Hardware: $20.58
Door: $107.00
Window: $59.99
Poly Panels and Fasteners: $149.82
Foam Weatherstripping, Liquid Nails and Caulk: $72.50

Total: $574.45
Tax: $47.39

Grand Total: $621.84

Extra Bits

The following items are things that I already had prior to this project:

Growlights:

Humidifier:

Fan:

Any standard oscillating fan will do. I believe mine was $12 at Big Lots several years ago.

Stud Finder:

Chalk Line:

Power Tools: