Sandy Miller

Hi all. Planning a small rear extension. Our post code is RH12 5XQ. Building Control have told me due to the proximity of a neighbours mature oak I will need more than the standard foundations (i.e. option B below) I need a ball park as to how much this is likely to cost, if it's as bad I think it will kill the budget and we won't be able to afford any of it and I won't bother getting the drawings done. Tried a few local builders with this question but they didn't even bother to reply. A) Standard 10 meters of trench 1m deep + 13m2 of concrete floor. B) Standard 10 meters of trench 2m deep + compressible material + 13m2 suspended concrete floor. What would be most helpful to us is, if someone could say something like; for just the foundations and assuming there are no snags, then for each you're looking at around A) ? thousand B) ? thousand I know there are a ton of things that will affect the cost of any job. I just need some helpful person to take a stab at it. Any ideas on this will be so helpful, thanks.