Does the designer involved much the building work after the

Hi
My husband is going to be the owner builder for our extension （190 sqm, kitchen, bedrooms, toilets etc)
We are going to hire the subcontractors to do the concreting, framing, roofing etc for us.
Just wondering does the subcontractors need much advice from the designer (who design our extension) or they can perform the job by just looking at the plan?
How hard does the owner deal with the building surveyor without the designer?

Thanks

Hi Karen5784
You will need to check with your Local Council first
generally you will require Plannings and Building Applications and documentation
Designers generally deal with Planning but not Engineering
Alternatively, find an engineer that also does the initial Planning/designs
If it's Designed & Engineered in 3D then ask for quantities, etc
as it will greatly assist you in the owner Build process
Structural Certification hierarchy generally goes (First) Engineer (Compliance & Non Compliance )->Building Surveyor (Compliance only) ->Designer ( can't Certify)
Please check my uploaded Images to Homeone for 3D Bim Design