We have Geotechnical report which is dated 2011- back when the land was subdivided. We are only just now at the stage of going ahead with building, and will be doing owner builder. I’m trying to put together an estimate of costs for the slab, and have a few uncertainties:
1. In the report from 2011, soil was classified as P due to deep (>0.4m) uncontrolled fill. Could this have changed? Should we get a new geotechnical report done?
2. Geotechnical also recommendeds piered footing system. What does this mean? How can I estimate the costs here?
3. Does the concrete mpa requirements vary due to the soil classification. What’s a worst case I can use for estimating costs?
4. Any other additional costs associated with P class soil?