The Best Type of Greenhouse Foundation to Build

Before you start building your new DIY greenhouse, you first need to decide on what type of greenhouse foundation you’ll use to support the building. While you have a few choices in the type of material you use, it’s important to understand the options so you can decide which one is right for your area and the greenhouse you are building.

Permanent or Temporary?

One of the main factors in deciding on which foundation you eventually use is whether you ever plan to move the greenhouse in the future or are adding it to your property as a permanent structure. Many times a homeowner will want a greenhouse for growing plants or vegetables and expect to remove it if they ever sell their home. These types of greenhouses are typically smaller and easy to set up. Because they are only temporary you’ll want to have a foundation that can support the weight of the greenhouse but is also easy to remove when the time comes. A simple wooden foundation would work well for this type of application and is an easy and inexpensive option that makes it easy to move your DIY Greenhouse later if needed.

Concrete Provides a Very Firm Foundation

If you are building a larger greenhouse or live in an area of the country that has very cold winters, you might want to consider a more substantial foundation. Using a poured concrete foundation would be a stronger and more permanent option that can support a greenhouse of almost any size and shape. This type of foundation needs to be installed deep into the ground around the perimeter of the greenhouse. The main advantage of this type of foundation is its durability, which can prolong the life of your greenhouse. Even though a concrete foundation is a little more work than other options, it is well worth the effort for the extra years it can provide as support for the building. Once properly installed, a concrete foundation will offer all the support and anchoring strength your greenhouse requires.

Another option, which is somewhat of a hybrid of the other two, is a beam and post foundation. This type of foundation is similar to the concrete version but instead of tracing the perimeter of the building, it relies on several posts for support. These posts can be concrete or treated wood and are usually installed at an equal spacing around the edge of the greenhouse and buried to a depth below the frost line. These posts are then use to support the beams which form the floor of the greenhouse. Unlike the other foundations, a post and beam solution will actually raise the structure off the ground slightly. This type of foundation provides very good support for almost any sized greenhouse and still allows you to easily move the structure later if needed. The posts can be removed with a little digging and the area returned t its original condition. The advantage that this type of foundation has over a simpler wooden one is that it provides a much stronger anchor for a DIY greenhouse in windy areas. Because the supporting posts are buried in the ground, they can hold the greenhouse firmly in place and help avoid the small movement that can take place with a standard wooden foundation.

Check Your Greenhouse Plans for Suggestions

Many greenhouse plans will outline the best type of foundation for the model you’re building and can be a big help in the decision. You also need to consider the area of the country where you live. If you have harsh winters you’ll need to build a foundation that can resist the movement of freezing ground in the winter months. This typically involves ensuring the base of the foundation rests below the freeze line. This ensures the structure above the foundation won’t move or twist when the ground freezes.
The other consideration is the ability of your foundation to anchor the greenhouse in place. Your DIY greenhouse will be exposed to wind and weather and needs to be firmly attached to the foundation to resist being moved or blown over in bad weather. Using a foundation that can supply this anchoring is critical in getting the most use out of your new greenhouse and providing the support it needs for years to come.

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