Although it is expensive it is not nearly as expensive as it would be if we used a concrete floor and we
know for a fact that this style of floor will give us the best results on the long run because it is deep
enough to absorb all the water excess and keep the weeds from growing inside the building.
4.2.4 Foundation
The foundation of the greenhouse is responsible for holding the entire structure in a good standing.
Normally a footed frame of two feet deep is enough to hold the structure in place, but in regions where
there is unusual weather conditions, like in New England, or where the floor freezes during periods of
the years, a deeper foundation is required.
When the ground freezes it oscillates, making the structures on top of it move. To prevent this from
happening, a deeper foot is necessary. The frost bite, usually, only affects the first couple of feet,
therefore, the foundation should be at least four feet deep to avoid the disruption of the structure.
To achieve that, we are recommending the use of SONOTUBEs which costs about $7.00 apiece. A
sonotube is shown in Figure 38.
Figure 38. Sonotube being installed (Roberts J. , 2012)
This particular sonotube is sited on a block of concrete, but there is other cheaper options like the Redi
plate sold at Home Depot for about $20.00 apiece.
After digging the hole and placing the sonotube in it, it is filled with concrete and a wood post is than
placed in the middle of it to build the structure from there.
A good rule of spacing for small structures is to have one sonotube every eight feet. This distance
ensures a strong foundation and a good spacing in between them.
An estimated cost of the materials used in the construction of our greenhouse is show in Table 14 ,
other choices of materials and their costs can be found in appendix B.
Materials Amount Dimensions Sources Total Cost
Wood Various Plywood plus (local) ~$2000.00
Paneling