The Davison Test: How We Ground-Test Every Garden Room Before Installing the Foundations

Davison Test rig with hydraulic ram, digital load gauge and steel beam testing ground screw foundation capacity on site

At Bexley Garden Rooms, we carry out ground testing using the Davison Test to test ground stability and the structural integrity of the ground screw foundations.

It’s a simple, practical on site check that shows us exactly how the soil behaves before we install any garden room screw foundations. Instead of relying on generic soil data, we drive a test screw into the ground at an installation depth and apply controlled pressure to measure how much load the soil can safely take.

We’ve also developed our own in-house app to support this process. It calculates the structural load of the building, identifies the ground and soil conditions, creates the required garden room screw layout plan, identifies the correct screw types for the project and generates the testing plan that each team follow on site on each individual build. This means every foundation design is based on real data from your property, not assumptions.

The Davison Test was originally developed as a quick, reliable way to assess ground conditions without the cost or disruption of traditional soil investigations and it’s now widely used across the industry. Combined with our app, it gives us a clear, accurate picture of what your project needs.

For you, it means we know from the start whether the ground is suitable, how many screws are required and exactly what specification they should be — giving your garden room a stable, long lasting foundation designed around your actual site.

Screenshots form the app

Building load calculator

Screenshot of Bexley Garden Rooms' in-house app showing building load calculation results including UDL values and screw type load summary

Screw layout plan designed by ‘AI’

Screenshot of app-generated screw layout plan showing corner, mid-perimeter and spine screw positions for a garden room foundation

Results page for prescribed load test

creenshot of Davison Test results page showing a pass result and Davisson offset line graph for ground screw load testing

Ready to transform your home with BGR?

If you’re considering a bespoke garden room for your home, or are interested in any of our other services, simply get in touch using the details below or the contact form, including a phone number.

We require your number to take more thorough details from you and therefore provide a more accurate estimate; we won’t use it hound you with unwarranted calls. 

A member of our team will then be in touch to help you start your Bexley Garden Rooms journey.

Please note our office hours are Monday–Friday, 8:30am–5:30pm (excluding bank holidays).