Site Insurance.

Self Build Zone and Aviva seem to be the insurers best suited to self-builders. You need public liability Employers liability even if only your friends will be helping You will save money hiring large plant if you have your own insurance to cover hired-in plant theft. A general policy might be happy for you to excavate a maximum of 3m. Getting insurance to go a little deeper can cost a great deal more. You may have an architect who insists you bury a sump beneath your basement for leaking water to be pumped out of, despite BS8102:2022 dissuading you from that idea, and burying a sump might take your excavation down to 5m where you could find water, danger and have no insurance. Many basements need to be dug a little bit more than 3m, for instance

1. Remove and set aside your topsoil around the new structure before you excavate. Usually 0.10 to 0.20. In this example 0.15. Total saved 0.15.


2. Persuade your design team you don't need insulation beneath your basement floor screed because 2m of soil before heat escapes to the air is already more than adequate. In this example 0.07. Total saved 0.22.


3. Reduce the screed to 0.04 because it is only necessary to level the structural floor slab. In this example 0.04. total saved 0.26.


4. Change your ground floor construction from the usual 0.15 beam and block covered in 100mm of concrete screed (0.25) to 250mm deep engineered timber floor joists. Saving zero.


5. Engineered timber floor joists allow you to put all your services through the joists. You don't need an additional service void. In this example 0.15. Total saving 0.41.

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