Can I use self-install ground screws for my garden room?

Yes, and no. Various factors influence the effectiveness of self-install ground screw foundations.

Some considerations are:

  • Ground conditions and soil type. Not all soil is the same and each will offer different stability and load-bearing capacities.
  • What you are supporting. It is essential to consider what you are installing on top of your ground screw foundation. Professional ground screws vary in size and offer different levels of stability for all sizes of projects.
  • Ground levels. If you have sloping ground, you may require different lengths of ground screws to ensure your foundations reach the correct depth for your project.
professional ground screw vs self-install screw

Choosing the right ground screw is imperative to achieving the correct support for the structure you are building on top. Your foundations are one of the most critical parts of your project and if not installed correctly can lead to subsidence very quickly, costing far more to rectify than investing in the correct ground screw from the start.

As a simple rule, if you can install a ground screw by hand, it has not required a significant amount of force to do so and will only be sitting at a minimum depth. If installed easily you should ask yourself, how stable is it and will it be likely to sink?

There is also a high probability your foundations are subject to ground heave – which is the upward movement of the ground usually associated with the expansion of clay soils, which swell when wet. As the soil generally cannot expand downwards or sideways, the result is that the exposed upper layers of soil commonly referred to as the ‘heave zone’ rises and with it the screws will move if not secured to a greater depth.

At No More Digging, we have many years experience supplying and installing ground screw foundations. We understand that not all ground conditions are the same and that not one size fits all. This is why we carry a range of sizes when we attend any project installation, and we will choose the correct ground screw to suit your specific application and ground conditions.

Professional ground screw foundations vs self-install screws

The images give you an idea of the difference between a self-install ground screw and a professionally installed ground screw. Our standard ground screws range in length from 1050mm to 2100mm and are a minimum of 76mm in diameter. A self-install ground screw is tiny in comparison.

When we install ground screw foundations for garden rooms, our benchmark would be our 76mm diameter x 1250mm long screw, which ensures we reach the depth of load-bearing stratum that offers excellent all-around stability. If needed, we can install to greater depths until we are confident that we have achieved the load-bearing targets for your project, including meeting any required safety factors.

Contact your local team for some free advice to ensure that you get your project off the ground on the right footing.

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