Ground screw foundation

[DesH]

Hi

I’m looking to put a SIPs extension on our 1910 bungalow. 
I’m having difficulty finding a structural engineer who can calculate the size and centre of the ground screws. We have had a pull test carried out and have the test certificate.

Can anyone help or advise?

[JohnMo]

16 minutes ago, DesH said:

difficulty finding a structural engineer who can calculate the size and centre of the ground screws

I was told by the architect that ground screws and permanent building are not compatible. Reason being, the design life of the screw is way shorter than the building. So the screw will fail first, which isn't good.

 

Trouble with a structural element that can corrode being in contact with the soil is the corrosion. Soil can be acidic, alkaline, wet, and there is lots of oxygen present. Without very careful material selection you will have issues down the line.

 

Put in normal foundation, make sure its well insulated, sleep soundly not thinking about issues, that may occur in 20 years, that cause the extension to fall down.

 

Screw piles have their place, for sheds and summer houses, which are not permanent buildings.

[Gone West]

It's not usually acceptable to use different foundation types on a house and an extension due to potential differential movement. There is an old thread about ground screws and a couple of links to Grand Designs that used ground screws.

 

 

https://padstudio.co.uk/project/chestnut-farm-modern-sustainable-farmhouse/

 

https://www.arborarchitects.co.uk/projects/redbrook

 

[DesH]

Thank you for your advice with this. I’m now leaning toward a concrete footing. The bungalow is standing on stepped brick footing about 600mm deep