I have started to dig the foundations for my extension, and have found that the foundations for my house pertrude away from the house about 6", for the full width of the house (approx 5m). Not only this but it seems that the house is built on trench fill foundations whereas my designer specifed that the extension should be built on deep strip foundations.
I am after a little bit of advice on:
1) If my house is on trench fill foundations does this mean that my extension will also need to be on trench fill foundations?
2) If I do need trench fill foundations then will I have to take the house foundation back to the house, or key into the house foundations in some way?
3) If I continue with deep strip foundations then what do I need to do to tie it to the current foundations?
Any advice would be appreciated.