Dependent on the size of the new build between 40- 48 weeks
A standard home extension takes between 8-12 weeks to complete
Not all extensions or renovations require you to move out but you should consider if you are replacing a kitchen then you will need alternative arrangements.
Once the final plans and contract have been signed off the build will usually start within a few weeks, this is dependent on a variety of factors that will be discussed at the time.
Yes you can. A visit to a finished job will need to be arranged with the current home owner.