Hi there. I have ordered a log cabin to use as a garden office. I plan to put it on a pre existing concrete base that used to have a shed on it. Now here are the two problems: Firstly I need to enlarge the base. It is currently 310cm x 240cm I need to add to the back and side to make it - 420 x 270. That I am less worried about. I can dig that out and fill it in with more concrete right? The main problem is the old base has a small slope (assuming it was to help drain water). Its about 25mm off on the spirit level. Sloping away from the side I need to extend from (if that makes sense?). Needless to say the log cabin's bearers need to be on flat level ground. Ideally I don't want to relay the whole base, but hope can I level the bearers safely in a way that will take the weight. about 1000kg. PLEASE HELP.