01
How much weight can a ground screw hold?
There is no single load capacity that applies to every ground screw. It depends on the screw size and shape, how it is installed, the ground, the direction of the load and how the building connects to it.
Ground screw load calculations
Capacity is a
system question.
A ground screw does not have one universal safe load. Capacity depends on the screw, the ground, how deep it is installed, the direction of the load and how the building fixes to it.
Quick answer
How much weight can a ground screw hold?
The answer depends on the complete installed foundation. Product load figures are useful, but you still need to know what the building puts onto each support, what the ground is like and how the screw connects to the frame.
For a structural project, the design should check downward load, uplift and sideways forces where they apply, then make sure the screw layout can carry them safely.
Test what matters
Load figures need evidence behind them.
Testing and installation records can help show how a ground screw performs. The important thing is to use the results for the actual screw, ground and load on the job rather than turning one test into a blanket marketing claim.
Load cases
The screw sees more than downward weight.
01
Compression
Downward reactions from the weight of the structure, finishes, occupancy and other imposed loads.
02
Uplift / tension
Upward force, often caused by wind trying to lift part of the structure.
03
Sideways load
Horizontal forces and how the screws and fixings stop the building moving sideways.
04
Wind & snow
Weather can add extra forces that the foundation needs to resist.
How the calculation works
From building loads to ground screws.
01
Work out the loads
Use the building layout to work out what each support point needs to carry.
02
Check the site
Look at the ground, levels, services and machinery access.
03
Choose the screw
Select the screw size and depth using the product data and site information.
04
Record the design
Confirm the screw layout, fixings and any calculations or testing needed for the job.
Product data
Why generic capacity tables can mislead.
A table may describe a product test condition, but the installed foundation still depends on actual ground, spacing, installation, connections and the structural load case. Treat product data as part of the design input, not the whole design.
Foundation design
Why the screw positions matter.
Adding more screws is not automatically the answer. The positions have to match the beams and frame above so the building weight reaches the ground in the right places.
Load & capacity FAQs
Ground screw load questions, answered.
Direct answers on capacity, screw quantity, torque, structural calculations and how the complete foundation is assessed.
02
How are ground screw load calculations done?
The calculation starts with the loads from the building at each support point. Those loads are then checked against what the chosen ground screw can carry in the actual ground, including downward load, uplift and sideways forces where relevant.
03
How many ground screws do I need?
The number of screws comes from the building layout, not a fixed screws-per-square-metre rule. Beam spans, floor layout, heavy point loads, uplift, sideways forces and the ground can all change the final quantity.
Start a project brief04
Does installation torque tell you ground screw capacity?
Installation torque can be useful information on some ground screw systems, but it should not be turned into a load capacity using a generic rule. Any torque-to-capacity relationship needs to come from the data for the actual screw system being used.
05
Do ground screw foundations need structural calculations?
If the ground screws are supporting a building, the foundation should be based on the building loads and layout. The amount of calculation, testing and paperwork depends on the job and any Building Control requirements.
Read the compliance guideStructural project
Have drawings or load information?
Send what you have and we can help work out the ground screw layout and what technical checks are needed.