One of the reasons that screw piles have grown in popularity in recent years is that they can be used in a range of conditions. With very little need for any kind of groundwork. But what about when you’re dealing with rocky ground? Can screw piles be used in rocky ground? And are there any precautions that need to be taken?

Screw Piles in Rocky Ground: What Do You Need to Know?

Can you use screw piles in rocky ground?

This is a bit of a yes and no answer. Screw piles can be used in a wide range of soil conditions. And if you want to build on poor quality ground, where small rocks are strewn through the earth, ground screws may be a viable option. But only if the rocks are smaller than an inch or two in diameter. Screw piles will be able to push smaller rocks aside, but they will not be able to navigate larger rocks.

Can you insert screw piles into rock?  

As a general rule, you cannot use screw piles in solid rock. While the occasional exception can be made, where a lead helical plate may be advanced into the first few inches of weathered rock, in most instances this is not recommended. So, if you have plans to build upon rocky surfaces, we would advise finding alternative solutions.

Are screw piles any good in gravel?

While screw piles are perfect for sandy conditions, they are not recommended for use in gravel. This is because gravel prevents them from advancing correctly. So, any mass with a grain size of more than around 60% of the pitch of the helices will be unsuited to screw pile installation.

How to install screw piles in rocky ground

As long as you are working in ground with small rocks on otherwise suitable soil – clay, sand, peat, loam, chalk – you should have no problems installing screw piles. And you can go about installation in a couple of ways.

·         For smaller projects, you can install screw piles by hand. Simply make a small hole to anchor your piles, and rotate them, using the appropriate tools.

·         If you need to install larger helical piles, or a greater number of them, you may wish to employ groundworks vehicles. Excavators and skid steers both do the job quickly and efficiently.

Screw piles are like any other form of tool: They perform brilliantly if used correctly. When installed in the right conditions, they can be a highly durable, low-impact solution for providing foundations for a range of structure types. Sheds, decks, piers, stages, garden rooms, even home extensions. But before you plan an installation of any kind, it is always wise to have your soil surveyed. That way, you know exactly what you’re dealing with. And you can be sure that you are using the right equipment for the job.

If you need help finding the right screw piles for your next project, get in touch with UK Helix. 

Disclaimer –Information in this blog does not in any way constitute building advice or guidance for private or commercial building projects.