Lean-To Greenhouses

A lean-to greenhouse has its pros and cons. Advantages include convenient house access, better heat retention because one side of the greenhouse is a solid wall which loses less heat than glass, and an attached greenhouse can fit into a more compact space. Disadvantages include the height needed on the wall to which the greenhouse is being attached, obstacles on the wall (such as windows and doors) that need to be worked around, and potential building code issues. Here are some things to think about:

Do you have enough height?

A greenhouse roof needs to have enough slope to prevent leaks and dripping condensation. We recommend a 4 in 12 roof pitch as a minimum. So, a lean-to greenhouse extending 6ft from your house needs a minimum 8ft of height, with an additional 4 inches for each additional foot the greenhouse extends from the building wall.

This lean-to Tropic model greenhouse is nestled under the eaves of the house on a 32″ high Sturdi-built wood base wall. Make sure there is enough room under the roof overhang for the greenhouse roof vents to fully open.

On the right, this location has lots of height available. This Garden Sunroom is set on an 18″ concrete base. Since the base has no built in vents, a jalousie (louvered) window is added to provide extra ventilation.

This greenhouse at the left was custom made to fit under the overhanging eaves of the house. The glass roof extends only a short distance from the roof line and special glass walls were designed to fill the under-roof space.

Do you have obstacles to work around?

The Garden Sun Room greenhouse on the right had a window to be worked around We made sure the greenhouse would be tall enough to clear the window. On cold, sunny days when the greenhouse warms up, the windows can be opened to let warm air from the greenhouse into the house.

The Solite greenhouse on the left was carefully sized to not interfere with outside utility boxes. Note how it is also easily accessed from the house.

On the right, this Garden Sun Room has been customized to fit under the eave overhang and around windows, to take advantage of the winter sun

Do you have a good spot to put a lean-to greenhouse?

You need to have a wall that is large enough, in both length and height. It also should be convenient to the house so you can enjoy your greenhouse even when the weather is terrible.

The Tropic style greenhouse on the left is attached on the end of the house, and covers a door going directly into the garage, providing convenient access.

P5100023 To the Right – A custom designed Tropic model greenhouse is carefully wedged against the house, partially sunk into the ground to help conserve heat and fit the space.

Are there code issues to be worked around?

Building code requirements vary widely from city to city, so there are no hard and fast rules. Our standard greenhouses are designed for horticultural use, not living space. As such, they sometimes do not meet all living space code standards that might be required when attaching to a house.

Our Garden Sun Room model is designed with building code standards in mind, with tempered safety glass in the roof and double strength in the walls, along with our double glazing Thermal Option for extra insulation. Tempered glass, double strength glass or twin wall glazing can be added to all our greenhouse models. We can make modifications to our various greenhouse models to help meet codes. We will do all we can to help you work through issues with the building dept., but some requirements are costly. Free Standing greenhouses, especially those under 200 sq ft., generally have fewer code requirements. Lean-to greenhouses attached to garages are often not subjected to the permitting process as well.

Sometimes code requirements are less stringent for greenhouses attached to out-buildings. Left, a Tudor model lean-to is attached to a garage.

This 7ft wide Deluxe lean-to greenhouse is built against a stone wall rather than a house wall. The masonry wall provides solar mass, helping take advantage of the sun’s energy.




This 5½ ft wide Solite Lean-to greenhouse provides a snug place to over winter plants.

The compact Jacuzzi in this 9′ x 12′ Garden Sun Room is a relaxing place to end a day. Heat and humidity lost from the Jacuzzi is good for the greenhouse environment.

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If you’re in the Portland, Oregon area, please stop by our showroom!
We’re open Monday through Friday from 8am to 4:30pm. Weekends by appointment.
11304 S.W. Boones Ferry Road
Portland, OR 97219
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