Price considerations for a greenhouse foundation
Costs of a greenhouse foundation can vary widely based on labour and material costs in your area. Always base estimates on a site inspection as certain conditions can greatly affect cost including:
Slope:
If your yard has a significant slope this could mean the difference between 2 years of concrete and 5 yards of concrete, Also, the hours of labour need to be factored in since a few hours may be needed to dig out a retaining wall.
Ground Quality:
Is there a presence of moisture or large rocks that need to be considered before laying the foundation? Will you need a mini excavator to clear the area?
Accessibility:
Another factor to keep in mind is how easily accessible is your yard. How will the contractor bring materials into your space? There have been instances where the customer's yard is difficult to access, even by wheelbarrow, and gravel needed to be carried in by hand, bucket by bucket full. Not a fun day, but great exercise!
Material Costs:
Depending on your location, prices may change for certain materials. For example, if you are set on having a cedar-built foundation and live in New Mexico it will cost you significantly more than your friends in the Pacific Northwest. However, if you go with readily available materials in your region, you can often save money. For example, a customer from Texas used beautiful limestone for her greenhouse floor because it can be locally sourced.
Labour Costs:
If you can lay the foundation yourself, you can save in this area. Not everyone has the means or the back strength for the job.
Approximate Foundation Costs:
| 8x12 | Pressure Treated Wood (1 row on grass or concrete pad, gravel and pavers) |
$900 - $1400 |
| 8x12 | Slab (1 - 1.5 yards of concrete based on a 4" depth) | $2,500 - $4,00o |
| 8x12 | Perimeter Foundation (3 - 4 yards of concrete split between the kneewall and concrete curb) | $5,000 - $7,000 |
| 12x16 | Pressure Treated Wood (1 row on grass or concrete pad, gravel and pavers) | $1,200 - $1,700 |
| 12x16 | Slab (2 - 3 yards of concrete) | $4,000 - $5,500 |
| 12x16 | Perimeter Foundation (5 - 8 yards of concrete) | $9,000 - $12,000 |
| 16x20 | Pressure Treated Wood (1 row on grass or concrete pad, gravel and pavers) | $1,800 - $2,500 |
| 16x20 | Slab (3 - 4 yards of concrete based on 4" depth) | $3,000 - $6,000 |
| 16x20 | Perimeter Foundation (7 - 10 Yards of concrete based on footing buried to meet municipality code and with 16" + kneewall) | $13,000 - $18,000 |