Ground Mount Solar Foundation Types

Ask our Solar Engineering Experts: Choosing Ground Mount Foundations & Racking

In Industry Perspectives by info@pvcomplete.com

Ask Our Solar Engineering Experts

“We’re a successful solar installer, but have focused exclusively on residential and small commercial roof mount projects. We have a customer who is interested in doing a ground mount project. What roof vs. ground mount project differences should we be aware of? What do we need to know before we dive in?”

With all of your roof-mount PV experience, you know that racking system attachment varies based on the roof type, with different attachment approaches best suited to metal, composite and more. The same is true of ground mount foundations, and therefore racking selection. Different site conditions and project parameters will call for different solar racking systems and foundations.

There is a simple decision matrix you can use to make your equipment selection.

Terrain

First, is your terrain flat, sloped or variable?

It comes as no surprise that flat terrain provides you with the wide open option to use virtually any racking system. But in the case of either sloped or varied terrain, it’s important to match your topography with the racking system best suited to accommodate it. If your site is either sloped or has varying terrain, be sure to look for a racking system with the flexibility to accommodate changes in grade.

Soil

Another factor in racking system choice is the soil.

For example, ground screws are best suited for rocky or cobbly soils. Concrete piers, driven piles or soil anchors are best suited to clay soils or silty/sandy soils.

Once you’ve identified your foundation options, look for a racking system that is designed to allow for installation with that foundation type. Check with the manufacturer to ensure their product is compatible with your soil-appropriate foundation type. 

Scale

The size of your ground mount installation should also play a role in choosing your foundation type and racking system. 

For example, since driven pile foundations require expensive heavy equipment to install, they are only cost effective for projects larger than a certain size. They are most often not the best choice for residential or small commercial ground mount solar projects, which are most often best suited to manual installation methods. 

Location

When choosing a foundation type, consider the logistics involved in getting it on-site. If you need installation equipment, determine whether it is available nearby. Or in the case of concrete piers, the site’s distance from the nearest concrete plant can impact project costs and timelines.

What About Homemade Racking?

Don’t be tempted to try to build your own racking with unistrut or other DIY components. While solar ground mount racking may appear simple to construct, in reality engineered systems have been wind tunnel tested, UL listed, tested for grounding and bonding, corrosion tested and pre-stamped for structural loads. They also come with warranties that average 20 to 25 years. Don’t risk your solar investment with a build-your-own system.

We’re Here to Help

PVComplete’s design services team is here to answer your questions about ground mount foundations, racking and other solar project essentials, and help steer you in the right direction. 

The solar engineering experts at PVComplete are familiar with virtually every quality racking solution and can help you match the right rack and foundation with your exact project site conditions to best achieve the objectives you have for your solar farm and ensure years of successful energy production.

Email us to start exploring your solar ground mount options.