How to build a lean to greenhouse

This step by step garden project is about how to build a lean to greenhouse. Building a lean to greenhouse will help you grow vegetables and flowers in your own garden. Gardening is one of the best choices if you need a hobby or you just want to relax and reduce the stress level. Attaching the greenhouse to your house is an option, but you need to make sure the moisture won’t damage the structure of your home.

A lean to greenhouse is the ideal project for you, if you want to grow vegetables and flowers by yourself, but you don’t have enough space in your backyard. Don’t forget that you should pay attention to the preliminary steps, such as reading the building codes and get a permit, if needed. In addition, we recommend you to invest in quality materials that are resistant to moisture and sunlight.

Always adjust the size of the lean-to greenhouse to your needs before starting the actual construction. In addition, use a circular saw with a sharp blade to cut the components at the right size before assembling the frame together. Always align the components at both ends and drill pilot holes before inserting the screws to get the job done as a professional. Plumb the studs with a spirit level and check if the corners are right-angled, by using a carpentry square. See all my Premium Plans in the Shop.

Made from this plan

Building a lean-to greenhouse

Building a lean to greenhouse

Materials

• A – 2 pieces of 2×4 – 192″, 9 pieces – 46 1/2″ WALL
• B – 3 pieces of 2×4 – 46 1/2″, 1 pieces – 57 1/2″, 1 pieces – 70″, 1 piece – 30″, 1 piece – 89″, 1 piece – 14 3/4″, 1 piece – 7 3/4″ WALL
• C – 2 pieces of 2×4 – 192″, 9 pieces of 2×4 – 81″ WALL
• D – 2 pieces of 2×4 – 89″, 5 pieces – 46 1/2″, 1 piece – 33″, 1 piece – 23 3/4″, 1 piece – 14 3/4″, 1 piece – 7 3/4″ WALL
• E – 11 piece of 2×4 – 102 1/2″ RAFTERS
• F – 6 pieces of 2×4 – 22 1/2″, 6 pieces of 2×2 – 30″, 6 pieces – 19 1/2″ VENTS 
• G – 2 pieces of 1×3 lumber – 68 1/2″, 3 pieces of 1×3 lumber – 25″ DOOR

• 2 pieces of 1×3 lumber – 10 ft
• 4 pieces of 2×4 lumber – 16 ft
• 36 pieces of 2×4 lumber – 8 ft
• 11 pieces of 2×4 lumber – 10 ft
• 4 pieces of 2×2 lumber – 8 ft
• greenhouse film
• vent opener
• hinges
• rafter ties
• 2 1/2″ screws
• 1 1/4″ screws
• glue, stain
• wood filler

Tools

• Safety gloves, glasses
• Miter saw, jigsaw
• Chalk line, tape measure, spirit level, carpentry pencil
• Drill machinery and drill bits

Tips

• Build a loft to increase the storage space
• Secure the walls temporarily with braces

Time

• One Week

Related

• How to build a small greenhouse
• How to build a cold frame

How to build a lean to greenhouse

Building the side wall

The first step of the project is to build the frame of the lean to greenhouse. In order to get the job done as a professional, we recommend you to assemble the walls on a level surface. In addition, check if the corners are right-angled and drill pilot holes trough the plates, before inserting the 3 1/2″ screws into the studs.

Building the tall side wall

Build the opposite wall in the same manner described above. The only difference is that we recommend you to cut the top of the studs at about 20º, before attaching the top plate. In this manner, it will be a lot easier when fitting the rafters into place and you will reduce the amount of work needed. Place the studs every 24″ on center, in order to provide enough support to the structure.

Assembling the frame

Place the side walls on the chosen location and plumb them with a spirit level. Use wooden braces to lock the walls into place, before building the front and the back faces of the greenhouse. In addition, you could place the frames on top of 4×4 skids, as to protect them from moisture.

Front wall plans

Building the front face of the greenhouse is a straight-forward job, as you just need to attach studs to the bottom plate, after placing it between the sides of the construction. Plumb all the studs with a spirit level before fitting them into place. Leave enough space for a large door, otherwise you won’t have an easy access to the greenhouse.

Back wall plans

Build the back wall of the greenhouse in the same manner described above. The only difference is that you don’t have to leave space for a wooden door. On the contrary, we recommend you to place the studs every 24″ OC and to lock them to the plates, as tightly as possible. Check if the corners are right-angled, after fitting each component. Make 20 degree cuts to the top of the top studs.

Attaching the rafters

Build the rafters from 2×4 lumber and lock them into place with 3 1/2″ galvanized screws. Cut the ends of the rafters as in the image, if you want to get the job done as a professional. Double the rafters at both ends of the greenhouse, in order to add support to the structure.

Building the rafters

Use the information from the diagram to cut the rafters at the right size and shape.

Building the vents

In order to keep a proper temperature inside the greenhouse, we recommend you to fit wooden vents between the rafters. As you can see in the image, you can get the job done in a professional manner by yourself, by building 2×2 lumber. Fit the frame into place and lock them to the structure with metal hinges.

Attaching the door

Build the door for the greenhouse out of 2×3 or 2×4 lumber. As you can notice in the image, we recommend you to build a simple frame by cutting the components at the right size and lock them together with galvanized screws. Check if the corners are right-angled before fitting the door inside the door opening and locking it to the frame with hinges.

How to build a lean to greenhouse

Last but not least, we recommend you to take care of the finishing touches. In order to get a professional result, fill the holes and the gaps with wood filler and let it dry out for a few hours.  Check if there are protruding screws and fix the issue if necessary. Cover the structure with translucent polyethylene foil / polycarbonate sheets and lock it into place with strips of wood, over the greenhouse framing.

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