01
Are ground screws suitable for all soil types?
No. Ground screws can work in many ground conditions, but no structural foundation suits every site. The screw size, depth and installation method need to match the actual ground and the building.
Ground screws & ground conditions
The ground matters
at every support.
A postcode or soil label cannot tell you the right ground screw. The building and the actual ground at the site both matter.
Site conditions are part of the specification
Ground conditions
Different ground needs a different approach.
These are general pointers, not automatic yes-or-no answers. The actual site still needs to be considered.
01Often workable — assess the actual site
Clay & cohesive soils
Clay conditions can vary a lot with depth, moisture and local geology. Avoid selecting screw depth from a regional stereotype.
02System and density matter
Sand, silt & granular soils
Sand, silt and gravel can behave very differently depending on how dense, wet or layered the ground is and the shape of the screw being used.
03More checking may be needed
Made / disturbed ground
Fill and previously disturbed ground can be inconsistent. The job may need more information or testing before it is used to support a building.
04May limit installation
Rock & obstructions
Boulders, rubble or shallow rock can obstruct the intended screw path and may require a different installation or foundation approach.
05Needs project review
Wet or high-water conditions
Water conditions do not automatically rule ground screws in or out, but they form part of the site and durability considerations for the chosen system.
06Can vary across the site
Mixed / layered ground
Ground can change over a short distance. Do not assume every screw position will behave exactly the same.
What helps us judge the site?
Use what you know about the ground.
01
Existing ground reports
Any ground report or previous site information can help show what is below the surface.
02
Site history
Old buildings, filled areas, excavations, services and drainage can all affect the ground.
03
What happens during installation
The way the screw installs can provide useful information on some systems and projects.
04
Unexpected ground
If rock, rubble or soft areas are found, the plan may need to change rather than forcing the original layout.
Why the actual site matters
A town name is not a soil report.
Ground conditions can change from one property to the next, even within the same town or street.
Our local pages tell you where we work. This guide explains how the ground itself can affect screw size, depth and installation.
View UK coverageGround condition FAQs
Ground condition questions, answered.
Straight answers on clay, rock, made ground, wet sites and what can affect ground screw installation.
02
Do ground screws work in clay?
Ground screws can work in clay, but clay varies in strength, moisture condition, depth and behaviour. The project should be based on the actual site rather than a blanket claim that all clay is suitable.
03
Can ground screws be installed in rocky ground?
Rock, large stones, buried rubble or shallow bedrock can make installation difficult or stop a screw reaching the depth it needs. In some cases a different screw or a different foundation type will be better.
04
Can ground screws be used in made or filled ground?
Made or filled ground can vary a lot, even across a small area. The job may need more information, testing, deeper screws or a different foundation depending on what is found.
05
How do you know if ground screws will work on my site?
Start with what the building needs to carry and anything already known about the ground. Then check access and the screw options. Some jobs can be assessed from existing information; others may need testing or more investigation.
Read the foundation guideSite question
Already know something about the ground?
Send it with the building details and postcode so we can use it when reviewing the foundation.